Chapter 2
Year 2020

2.1 Thursday, December 24, 2020

2.1.1 Top new questions this week

These PDE’s no longer evaluate in version 12.2 as they did under 12.1. What can be done to make them evaluate under 12.2?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236895

These 399 PDE’s no longer produce result under Version 12.2 on windows. DSolve now returns unevaluated. These all evaluated under version 12.1. Why is that? And ...

asked by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 17 votes

answered by Devendra Kapadia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18617 12 votes

Travelling around Jupiter

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236843

Since we have soon historical conjunction of Jupiter and Saturn I have prepared code with visualization planet Jupiter and Saturn with moons. This code first been prepared for version 11.3 and with ...

asked by Alex Trounev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58388 16 votes

Numerically evaluating parameter derivatives of a hypergeometric function

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=237032

I am unable to obtain the numerical value of the derivative of the hypergeometric function. Please note that the (2,4,0,0) is the derivative with respect to the first and second argument

asked by Sachin Kaushik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58727 7 votes

answered by Mariusz Iwaniuk https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26828 7 votes

Numeric Solution Hydrogen Atom

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236980

I’m trying to solve the Schrödinger equation for the hydrogen atom without made the variable separation of the polar and radial coordinate. It is my test code to extrapolate to another system with its ...

asked by Jorge Castaño https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73029 7 votes

answered by Jorge Castaño https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73029 0 votes

Sum cause a Recursion problem

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236934

Sum[((-1)^(i + 1)*Binomial[n, i]*(n - i)!)/n!, {i, 1, n}]

This cause a Recursion problem.

As the comment said, If simplify the formula and then sum it, problem ...

asked by wuyudi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68689 6 votes

Is it possible to ask Mathematica to give the maximum value of a function over a specific domain?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236971

I have a function \(f(n)\) over \(n\in \mathbb {N}\). I want to know its maximum value over a very large domain, say \(n=1,2,3,4,...,10^6\). Is there a way to ask Mathematica to give me the maximum value of ...

asked by charmin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74550 6 votes

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 9 votes

Unrolling a surface

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=237045

The surface is determined by this parametric equation ParametricPlot3D[{Cos[],Sin[],z(2+ Cos[])},{,-Pi,Pi},{z,0,1}]

How to unfold the surface in Mathematica? ...

asked by expression https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7339 5 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 3 votes

2.1.2 Greatest hits from previous weeks

Conversion of Sine to Cosine

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=67521

I’m solving equations with many Cosines and Sines. And I want to convert all the Sines to Cosines using trigonometric formulas such as cos(x)=sin(x+pi/2). How can I do this?

asked by YongCheol Kwon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=23041 3 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 1 vote

How to ask Mathematica to imitate Andy Warhol’s pop-art painting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=59132

I tried to ask Mathematica to imitate Andy Warhol, let it convert a Marilyn Monroe’s portrait so that it looks like Warhol’s world famous pop-art painting. However, the result shown below is far from ...

asked by Putterboy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=16069 51 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 66 votes

Plot, extract data to a file

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19859

I need to save data that Mathematica uses inside the Plot command. The format that I would like to have is:

x1 y1 
x2 y2 
.....

asked by molkee https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5097 30 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 46 votes

My Girlfriend is going to prison...Save her with Math

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=135937

Salacious title, but true story.

asked by Prisoners Dilema https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46025 42 votes

answered by bobthechemist https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7167 23 votes

How to create animated snowfall?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=16881

Well, the title is self-explanatory. What sorts of snowfall can we generate using Mathematica? There are two options I suggest to consider:

1) Continuous GIF animations with smallest possible number ...

asked by faleichik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=219 40 votes answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 54 votes

Parallel and perpendicular symbol from Mathematica to LaTeX

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=46538

I want to get the following expression from Mathematica to LaTeX:

\[ \begin {bmatrix} E_{\parallel } \\ E_{\perp } \end {bmatrix} \]

I have tried to use inbuilt 'symbol' character from the special ...

asked by Steve Hatcher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13314 19 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 27 votes

1 Plot, 2 Scale/Axis

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=627

I would like to plot those two datasets on top of each other. But they have very different range on the \(y\) axis. How can I have two different axis?

I found the following on the help menu but quite ...

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 148 votes

answered by ArgentoSapiens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=92 151 votes

2.1.3 Can you answer these questions?

How to determine if a number is an integer power?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236779

How can I do simple tests like determining if an integer is a power of 2? Mathematically, the result below should be True, and I understand why it doesn’t work on MMa, but how do I do this test ...

asked by Jerry Guern https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=20042 1 vote

dot product of vectors with noncommutative elements

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=237042

I came upon an interesting problem. Suppose you have three vectors \(\psi =(a, b)\), \(\phi =(c,d)\) such that their components do not commute: \(ac\neq ca\), \(bd \neq db\) etc. (in general the vectors may ...

asked by geom https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68502 1 vote

How to Inherit Arrowheds size?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236932

I’m trying to write a Module that produces some arrows with custom Arrowhead shapes. However, I want the code external to the

asked by Wynne https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36616 1 vote

2.2 Thursday, December 17, 2020

2.2.1 Top new questions this week

Plotting the Star of Bethlehem

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236499

Christmas is around the corner! In preparation, consider the polynomial f[x_,y_]:= 1/10 (4 - x^2 - 2 y^2)^2 + 1/2 (x^2 + y^2) 

and define \(r=(f_x,f_y)\) using the ...

asked by fwgb https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44151 19 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 15 votes

Opacity gradient in custom legend

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236442

I need to produce the legend of a plot which encodes a color gradient together with a color gradient. In particular, I would like the image bellow to have the blueish edge faded and the redish solid:

asked by Marcelo Broinizi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53497 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

Circle Packing in Cone Texture

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236449

This is a cone with texture generated by PatternFilling in plane. The problem this texture mapping is not conformal. So my question is how to generated a pattern image which could suit a fixed height ...

asked by HyperGroups https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6648 5 votes

answered by cvgmt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72111 3 votes

Is there a Mathematica CUDA ode solver?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236625

I have a system of ODEs which I’d like to solve with many (thousands) different initial conditions. In the net there are articles that CUDA can speed up such computations, but I haven’t found ...

asked by Andrew https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=306 5 votes

How to properly use the function ThermodynamicData

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236558

I’ve been trying to use the function ThermodynamicData, and it is going fine when I try to calculate properties such as Enthalpy or Entropy or even phase as a ...

asked by Igor Stravinsky https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=35043 5 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 2 votes

How do I reorder and combine sublists based on sublist rankings given by another list?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236526

I have two lists:

asked by Gregorio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75996 5 votes

answered by wuyudi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68689 2 votes

How to convert cuboid to mesh efficiently

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236306

cuboids = 
Table[Cuboid @@ (pts = RandomReal[100, {2, 3}]), {i, 10000}]; 
 
Method1:

asked by HyperGroups https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6648 5 votes

answered by chyanog https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2090 6 votes

2.2.2 Greatest hits from previous weeks

Mathematica code for Bifurcation Diagram

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=13277

At the moment I am trying to construct a bifurcation diagram of the iterative function \(f(x)=\) \(ax-1.1975x^3\). I’ve scoured the internet for pre-made bifurcation diagrams and found many (mostly of the ...

asked by Mel https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3249 27 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 47 votes

What are the most common pitfalls awaiting new users?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18393

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...

asked by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 473 votes answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 285 votes

Calculate the 2D Fourier transform of an Image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=29203

I am new to Mathematica, and using version 8.0.

I would like to calculate the 2D Fourier Transform of an Image with Mathematica and plot the magnitude and phase ...

asked by user8727 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8727 17 votes

answered by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 33 votes

How to make the digits of go around in a spiral like this?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=109982

Here is a start.

MapIndexed[Text[Reverse[First[RealDigits[Pi,10,252]]][[Tr@#2]],#]&, 
 Table[{t Cos[t],t Sin[t]},{t,0,16Pi,0.2}]]//Graphics

asked by matrix89 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5379 57 votes

answered by Martin Ender https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2305 73 votes

How to make a Spherical Cow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=125043

Being a theoretical physicist, I always have a great respect for Spherical Cow. So I thought about making one myself. I am not sure how can I create (something considered to be the simplest!) this ...

asked by Sumit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8070 69 votes

answered by andre314 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5467 76 votes

How can I plot a graph of an integral?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=78451

I want to plot the following function:

\[\int \left (\frac {\Gamma (x+1)}{2}-\frac {\Gamma (x-1)}{2}\right ) \, dx\]

asked by Anixx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=651 4 votes

answered by k_v https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=24727 9 votes

How to tell Mathematica that certain variables are real/imaginary, integer-valued, etc

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66273 I’m trying to expedite some quantum mechanical calculations (expectation values etc.) by running them through Mathematica. When I say, for example,

asked by Matthew Brunetti https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22304 39 votes

answered by SquareOne https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19960 24 votes

2.2.3 Can you answer these questions?

Interpolation for different Parameters

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236606

I am rather new to Mathematica and I tried to find a solution for my Problem on my own, also looking through this site and the suggested Similar Questions, but I at least could not make out that my ...

asked by n00bBoi1 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76302 1 vote

Problem in iterative equation

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236532

I am solving the following iterative equation to calculate Tf and Cp as a function of temperature:

An initial attempt for a ...

asked by John https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72940 2 votes

Importing equations generated in subpackage to be solved in another subpackage

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236345

I have a package which contains two subpackages: one ("`MOTSimulator`MOTGenerator") which generates a systems of differential equations of the form

asked by crich https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76216 1 vote

2.3 Thursday, December 10, 2020

2.3.1 Top new questions this week

Find the equidistance curve between two curves

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235971

I have three function \(f(x)=x^x\), \(g(x)=\ln (x)^{\ln (x)}\), \(h(x)=\ln (x)^2\) and I want to find (numerically) \(C\) the center of the circle tangent to the three curves.

I think that one way is to find ...

asked by Domenico Modica https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76121 14 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 14 votes

Confused by results of FunctionDomain

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236138

Why does Mathematica give me the function domain of \[f(x)=(2x-3)^{\frac {1}{5}}-(2x+1)^{\frac {1}{5}}-(x - 3)^{\frac {1}{5}}\] as \(x\geq 3\)? I used this command:

asked by Ramez Hindi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76160 7 votes

answered by Roderic https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76085 8 votes

Cannot reproduce well-known summation result

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236149

Bug introduced in 4.2 or 5.0, persisting through 12.2.0.

Note: this is a repost of my OP on math.SE. I am posting it here because multiple users with different Mathematica versions have given me the ...

asked by Klangen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=49819 7 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 3 votes

Is there a way to get tooltip for parts of a string?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235911

Is there a way to get the tooltip to appear for parts of a string?

asked by user13892 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13892 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

Nice use case for symbolic tensors?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236188

I come from before the times of symbolic tensors in Mathematica, and am used to working with concrete tensors and custom commands to contract them using Transpose, Dot, etc. I recently realized that ...

asked by Stijn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69486 6 votes

answered by jose https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10552 2 votes

Drawing hollow disks in 3D with an sphere in center and small spheres on the rings

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236161

I was trying to draw the following logo of an atom using Mathematica, but I could only figure out how to draw intersecting ellipses, not a nice logo like below. Do you have any idea? And is ...

asked by Saeid https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=35814 6 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 7 votes

Solve‘DirInf[] Meaningful value or just a bug?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236077

Bug introduced in 4.1 or earlier and persisting through 12.2.0. or later

To the problem below, I get four independent, incomplete solutions, three in terms of ...

asked by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 6 votes

answered by Akku14 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34287 0 votes

2.3.2 Greatest hits from previous weeks

Why is raytracing so slow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219629

I’m trying to get some rays to bounce in a circle. But I want to be able to control the reflections, i.e. the direction the rays bounce in the circle. I have a MWE below, and it is severely limited by ...

asked by Tomi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36939 31 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 42 votes

Generate a Unit Circle Trigonometry

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2456

Struggling often with Trigonometry I would like to have some code to generate this Unit Circle Trigonometry. Would be of great help when I need to transform some data :

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 18 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 32 votes

Drawing a square root spiral

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66969

Here is a start. I’m looking for a nice way to draw it.

asked by matrix89 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5379 24 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 21 votes

How do I make a 3DPlot using cylindrical coordinates?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19076

I’m trying to plot a function of the form \(z(r,\theta )\) where \(r \in [0, R]\) for a finite R, \(\theta \in [0,2\pi [\), and z is the third coordinate, a function of the first two. I couldn’t find anything ...

asked by Learning is a mess https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5643 18 votes

answered by whuber https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=91 24 votes

How to calculate contour integrals with Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=34073

How to calculate the integral of \(\frac {1}{\sqrt {4 z^2 + 4 z + 3}}\) over the unit circle counterclockwise for each branch of the integrand?

asked by user64494 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7152 42 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 64 votes

Skip header lines on import

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=50718

When importing a data file what are the comment symbols for Mathematica? That is, given a file like this

blabla 
bulbul 
 
1 2 6 54 7 ...

what symbol do I have ...

asked by MaxJ https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=14687 20 votes

answered by george2079 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2079 18 votes

Using Export[] sends the file where?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8586

I am trying to use the Export command to convert a list of plots into a *.gif file, and the command runs and executes well, but I can’t find the file! Where is it ...

asked by Patrick Da Silva https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1785 37 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 51 votes

Can you answer these questions

Periodical sum of rows by a certain step

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236085

I’ve been struggling with one problem. I have a classic matrix in this example 12x4 such as: matrix = Table[i, {i, 12}, {4}]

asked by Jakub Petrj https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75456 2 votes

answered by Carl Woll https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45431 0 votes

Behavior of $MinPrecision seems to have changed between 12.0.0 and 12.1.1

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235851

I am running into a very weird bug where setting $MinPrecisionto some value (in this case 200 has a very different and ...

asked by Kvothe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45020 3 votes

HankelTransform problem

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236119

Somewhere in the following code there is a bug. The result should not be zero! FunctionExpand@HankelTransform[Sqrt[r] Cos[r], r, k, 1/2]

I think the answer should ...

asked by SolutionExists https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70331 1 vote

2.4 Thursday, December 3, 2020

2.4.1 Top new questions this week

Interpolation on an unstructured mesh

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235681

This may have a duplicate but I have spent some time looking and can’t find it. I have experimental data in the form of { {x1, y1, z1}, {x2, y2, z2}...} I wish to interpolate it so my thoughts turned ...

asked by Hugh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12558 10 votes

answered by user21 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18437 8 votes

Tower of Pisa function

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235495

I’m trying to construct a ’smooth’ function \(f : \mathbb {R}^2 \longrightarrow [0,1]\) such that all level sets \[\{ x | f(x)=y\}\] are circles in a way that \(f\) looks like the ’Leaning Tower of Pisa’.

asked by darksun https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75863 10 votes

answered by fwgb https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44151 7 votes

How can I ingest and analyze benchmark results posted at MSE?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235390

How can I ingest Mathematica / WL benchmark results posted at Mathematica Stack Exchange (MSE), like the ones posted here? Assumptions:

There are multiple answers with benchmarks posted

asked by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 10 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 12 votes

Construct a polyhedron from the coordinates of its vertices and calculate the area of each face

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235524

I have the 3D coordinates for a set of points. I want to construct the convex polyhedron with those points as vertices.

I know I can use functions like DelaunayMesh

asked by Dennis https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69969 9 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

Make an InterpolatingFunction periodic

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235403

Interpolation can make an InterpolatingFunction periodic with the option ...

asked by Chris K https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6358 8 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 3 votes

How do I place the Clock arrows inside this clock face?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235711

I am trying to program a clock, I have the face I want and the hands but I can not seem to put them together so they work.....

asked by Struggling Student https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75041 7 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 6 votes

How can I sketch a right-angled triangle?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235413

I would like to replicate this ellipse, but with a right-angled triangle (with smooth/rounded corners). The formula for this ellipse:

asked by nightcape https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75304 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

2.4.2 Greatest hits from previous weeks

Elegant operations on matrix rows and columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3069

Question

The Mathematica tutorial has a section ’Basic Matrix Operations’, describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 180 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 61 votes

Positioning axes labels

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=87388

I need to change the position of my axes labels such that the y-axis label is in the middle and parallel to the y-axis. I’d also like the x-axis label to be in the middle of the x-axis rather than ...

asked by John_dydx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7849 15 votes

answered by Virgil https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27697 16 votes

How to create word clouds?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2334

Word clouds are rather useless fancy and visually appealing plots, where words are plotted with different sizes according to their frequency in a corpus. Many applications exist out there (Wordle, ...

asked by István Zachar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=89 145 votes

answered by Heike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46 119 votes

How do I clear all user defined symbols?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=850

Is there some way to do this other than going to Evaluation -> Quit kernel and firing a new one up?

asked by niklasfi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=82 97 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 95 votes

What does # mean in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19035

I asked Mathematica to compute the following

Solve[c (1-x)^2-x^(1/4) == 0, x]

and it returned this:

  x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 c^4 

asked by ronanymous https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5730 38 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 64 votes

How to manipulate 2D plots?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=7142

When it comes to visual analysis, large datasets or data with intricate internal details often makes plotting in 2D useless, as the outcome is either just a fraction of the full dataset, or no details ...

asked by István Zachar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=89 134 votes

answered by István Zachar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=89 154 votes

How to make an inkblot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3345

How to effectively create a polygon that looks like a realistic inkblot? So far, I could come up with this (borrowing from Ed Pegg Jr.’s Rorschach demonstration):

asked by István Zachar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=89 86 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 51 votes

2.4.3 Can you answer these questions?

What is the fastest way to get the lowest eigenvalue and corresponding eigenstate in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235678

I tried to use the Arnoldi method to get the smallest eigenvalue and corresponding eigenstate for large matrix. However, Arnoldi did not give me the desired result:

asked by lol https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=40838 2 votes

How do I get built-in functions to use custom objects as if they were e.g. List?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235391

(This is part 2 of my earlier question, Can I overload Part for specific heads (a la overloaded array subscripting)?, which was well-answered as asked.)

Overview: My goal is to create a custom object -...

asked by Josh Helzer https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75893 3 votes

How to speed up this code (finding eigenvector with smallest eigenvalue)?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=235775

I have following code. The function TraceSystem is to take partial trace of matrix and I think this part is fine. The main code is below in dd and I think the main problem is in here for Eigenvector. ...

asked by lol https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=40838 1 vote

2.5 Thursday, November 19, 2020

2.5.1 Top new questions this week

3D Inclusion with structured mesh and coarse and arbitrary matrix

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234780

I am wondering if there is a simple way to define a structured 3D mesh (inclusion) like e.g. that and surround it with a corse and unstructured Matrix. It should be possible to refine both more or ...

asked by Max https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68812 15 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 8 votes

Smoother jelly / water effect on an image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234653

I’m trying to achieve a jelly / water surface effect. I’d like it to be a bit smoother. Here I am taking a triangulated rectangle and perturbing all points by a little random noise for each frame. ...

asked by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 14 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 15 votes

Can Mathematica be used to edit MP3 tags?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234564

Can Mathematica edit mp3 tags? I have a set of files and I’d like to batch process artist, album title, etc. I know other tools exist; I wonder if Mathematica can do it.

asked by GregH https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4393 11 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 15 votes

How can I put the edge of a rectangle inside it rather than outside it?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234866

Problem: when I draw a rectangle and put a coloured edge around it, the displayed edge is centred along the nominal edge and if it follows the same course as one of the axes then it does not show up. ...

asked by ruffle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=59886 7 votes

answered by Brett Champion https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69 5 votes

How do I invert my matrix?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234836

I have the following matrix \(M\):

\begin{bmatrix} 
P & p & 0 & 0 \\ 
pe_1 & Pe_1 & \sqrt{P^2 - p^2}q_1 & \sqrt{P^2 - p^2}r_1 \\ 
pe_2 & Pe_2 & \sqrt{P^2 - p^2}q_2 & 
\end{bmatrix}

asked by Anson Bdo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75764 7 votes

answered by LouisB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22158 14 votes

How to convert a Dataset into an indexed dataset / association-of-associations given a column header?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234931

Given a dataset as such

If "letter" is the header that is chosen, how do I convert it into an indexed dataset / association-of-associations? i.e. How do ...

asked by IntroductionToProbability https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=60568 6 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 6 votes

Automatically draw chords from n-1 points on a circle to a fixed point on the circle

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234729

I want to put n equally spaced points on a circle and automatically draw chords from all points to a fixed point preferably P(0,0). I have managed to draw the points and the circle so far with

asked by Guy Foxx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75736 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 5 votes

2.5.2 Greatest hits from previous weeks

How to find the position of elements in a list satisfying criteria

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=180

Say I have a list x={2,4,6,8,10} and I want to find out the positions of the elements that are greater than 7.

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 67 votes

answered by J. M.’s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 63 votes

Finding Limits in several variables

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=21544

Is there a way to find a limit of a multivariable function, like

\[\lim _{(x,y)\to (0,0)} f(x,y)\] with Mathematica?

When \(f\) is continuous, we can use \[\lim _{(x,y)\to (0,0)} f(x,y)=\lim _{(x,0)}\]

asked by Dominic Michaelis https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5899 31 votes

answered by whuber https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=91 42 votes

Why round to even integers?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2116

According to the Mathematica help:

Round rounds numbers of the form x.5 toward the nearest even integer.

For example:

Round[{0.5, 1.5, 2.5, 3.5, 4.5}]

gives

asked by wxffles https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=427 82 votes

answered by Per Alexandersson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=488 50 votes

Why is raytracing so slow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219629

I’m trying to get some rays to bounce in a circle. But I want to be able to control the reflections, i.e. the direction the rays bounce in the circle. I have a MWE below, and it is severely limited by ...

asked by Tomi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36939 31 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 42 votes

How do I identify the source of a "Tag times protected" error?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11982

I have some code that looks like

Table[ 
    a = 1; 
    b = {2, 3} 
    c = i;, 
    {i, 2} 
]

which gives an error:   Set::write: Tag Times in c {2,3} is Protected....

asked by dearN https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=204 29 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 35 votes

Mathematica command that allows it to read my intentions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=194384

In version 2.0 of Mathematica there was a command, ReadProgrammerIntentions[ ] which allowed it rapidly compose code that could solve problems simple to complex, ...

asked by MikeY https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=47314 52 votes

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 38 votes

How to make a Spherical Cow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=125043

Being a theoretical physicist, I always have a great respect for Spherical Cow. So I thought about making one myself. I am not sure how can I create (something considered to be the simplest!) this ...

asked by Sumit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8070 69 votes

answered by andre314 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5467 76 votes

2.5.3 -Can you answer these questions?

Setting pieces of "matrices" - unwanted behavior

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234703

I am constructing matrices whose elements are lists themselves (of varying length), and am (re)setting the entries of these matrices using among others the "All" command. It seems that in ...

asked by Stijn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69486 2 votes

system of coupled nonlinear pdes with FEM (magneto-hydrodynamic mass transfer)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234749

I’m trying to reproduce the magneto-hydrodynamic flow studied here using the nonlinear FEM functionality, and have been having trouble implementing the Neumann boundary conditions. Pardon the long ...

asked by George Varnavides https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41179 1 vote

Create a Cellular Automata rule in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234577

I want to create an image in a cellular automata, more specifically an image of an object, like a turtle for example. I found this article online, and i am trying to replicate the results for growing ...

asked by Joana Bugalho https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75694 2 votes

2.6 Thursday, November 12, 2020

2.6.1 Top new questions this week

How to cut a list by max sum

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234240

 {5, 10, 3, 8, 9, 8, 8, 4, 1, 7}

let maxsum=20, then I get ...

asked by wuyudi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68689 9 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 12 votes

Is it possible to ask Mathematica to stick two plots together to give a continuous plot ? (An example is given)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234373

I want to plot a function over a large range of \(x\). The problem is that for very large \(x\), even increasing PlotPoint to \(5\times 10^6\) and MaxRecursion 15, it does not give the whole result. But I ...

asked by charmin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74550 8 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 15 votes

ReplaceAll, Unexpected output

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234344

Each week I import a dataset, and every week the dataset differs in length (the number of records). After the import I need to do some transformations. One of these transformations is the ReplaceAll.

asked by Michiel van Mens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9590 7 votes

answered by Carl Woll https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45431 9 votes

Find All Permutations for Multiset

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234143

Take a list with repetitions, say {a, a, b, c}, and some permutation thereof, say {c, a, b, a}. I want to know which ...

asked by AccidentalFourierTransform https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34893 7 votes

answered by ciao https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11467 6 votes

Counting the number of edges between two graph partitions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234462

Consider the following:

g = RandomGraph[WattsStrogatzGraphDistribution[1000, 0.1, 5]] 
comm = FindGraphPartition[g, 2]; 
CommunityGraphPlot[g, comm]

asked by Caitlin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74961 5 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 5 votes

Summing over Partitions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234302

Imagine I have a list of integers \(l=\{l_1,l_2,...,l_{50}\}\), say, for example

l = RandomInteger[10, 50]

and I want to find how many ways there are of summing ...

asked by sam wolfe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=64001 5 votes

answered by Carl Woll https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45431 6 votes

Incomplete web image scraping

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234154

Occasionally when I scrape images from a webpage, such as:

Import["https://www.freeart.com/gallery/m/mondrian/mondrian.html", "Images"]

only a ...

asked by David G. Stork https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9735 5 votes

answered by Rohit Namjoshi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58370 4 votes

2.6.2 Greatest hits from previous weeks

Positioning axes labels

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=87388

I need to change the position of my axes labels such that the y-axis label is in the middle and parallel to the y-axis. I’d also like the x-axis label to be in the middle of the x-axis rather than ...

asked by John_dydx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7849 15 votes

answered by Virgil https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27697 16 votes

How to perform a multi-peak fitting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=26336

I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3). The ...

asked by Everett You https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1389 55 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 55 votes

How to generate a random snowflake

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39361

'Tis the season...

And it’s about time I posed my first question on Mathematica Stack Exchange. So, here’s an holiday quest for you Graphics (and P-Chem?) gurus.

What is your best code for generating ...

asked by Peltio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6745 140 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 181 votes

Figuring when the minute and hour hand coincide on a clock

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=573

I would like to list all possible times in a 12-hour period, where the hour hand overlaps the minute hand completely. This is really a question about three distinct things - to be done in Mathematica ...

asked by Steve D https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=191 15 votes

answered by Verbeia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8 21 votes

Is there an open source implementation of Mathematica-the-language?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=4454

I’ve seen questions before such as "What is the best open-source equivalent for Mathematica?", but that specific question (and that line of inquiry in general) cares more about the computer algebra ...

asked by sblom https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=178 122 votes

answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 85 votes

How to make a Spherical Cow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=125043

Being a theoretical physicist, I always have a great respect for Spherical Cow. So I thought about making one myself. I am not sure how can I create (something considered to be the simplest!) this ...

asked by Sumit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8070 69 votes

answered by andre314 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5467 76 votes

What’s the most difficult multidimensional integral that Mathematica has solved?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222184

I am interested in benchmarking numerical integration methods and am trying to develop a wider set of difficult multivariate examples. For my particular methods, I only want to look at non-negative-...

asked by ben18785 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19278 6 votes

2.6.3 Can you answer these questions?

Solving \(E[abXab]=Y\) for Gaussian \((a,b)\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234502

I have \(d/2\)-dimensional variables \(a,b\) jointly distributed as Gaussian(\(\mu ,\Sigma \)) in \(d\) dimensions, and need to solve the following equation for \(X\) \[E[ab^TXab^T]=Y\] This is equivalent to ...

asked by Yaroslav Bulatov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=217 1 vote

Problem with RunProcess

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234260

I’m trying to use the RunProcess function to run docker on Mac OS using Mathematica. But there is a problem:

asked by Wei Li https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75601 1 vote

Does NumberLinePlot give the whole results over a large domain? Or we need to increase its precision?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234324

I use this code over the domain \(x\in (0,300)\)

asked by charmin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74550 1 vote

2.7 Thursday, November 5, 2020

2.7.1 Top new questions this week

Why is there a discrepancy between JoinedCurve/FilledCurve and the underlying BSplineCurve segments?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233846

This may be related to How to discretize a BezierCurve?, but this question deals with BSplineCurves with specific SplineWeights, ...

asked by robjohn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=232 10 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 8 votes

Converting an equation with units to one without units

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233804

I may have a solution but it is not slick! See below Doing numerical calculations with functions that use units can be very slow. I would like to have a function or operator that can turn my functions ...

asked by c186282 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4515 6 votes

answered by march https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=29734 2 votes

Generate an e machine graph from transition probability matrices

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=234036

I am trying to generate this type of graphic:

see Fig.1a from https://arxiv.org/abs/0905.3587. This process is associated with two transition matrices

asked by AG1123 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36275 6 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 7 votes

Deconvolution approaches for 3D data

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233877

Building neural nets in the WL is great. I was in the process of rewriting a previous GAN of mine in the WL to see if I can get better performance, and was surprised to find that the standard ...

asked by BBirdsell https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=49805 6 votes

construct a lattice with a defined unitcell

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233863

We can construct a base-centered tetragonal unit cell by: LatticeData["CenteredTetragonal", "Image"]

But how can we construct a lattice by

asked by Inzo Babaria https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=33967 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

How to remove Null plot markers in QuantilePlot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233816

Bug introduced in 12.0 and persisting in 12.1.1

I want to change the plot markers of the data points in QuantilePlot. This seems pretty straightforward:

asked by Q.P. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27119 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 5 votes

Split in non-overlapping sub-lists with elements within an interval from the first member

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233767

I want to split a large ordered list into consecutive non-overlapping sub-lists, such that all elements are within an interval from the first member of the sub-list . For example:

asked by Oleg https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75470 6 votes

answered by WReach https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=142 7 votes

2.7.2 Greatest hits from previous weeks

Code that generates a mandala

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=136974

My little brother asked me to print original mandalas for coloring. I would like some idea on how to create them, but without color, so he can color them.

asked by zeros https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26849 73 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 97 votes

How to create word clouds?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2334

Word clouds are rather useless fancy and visually appealing plots, where words are plotted with different sizes according to their frequency in a corpus. Many applications exist out there (Wordle, ...

asked by István Zachar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=89 145 votes

answered by Heike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46 119 votes

How can I draw the Olympic rings with Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8885

How can I draw the 5 interlocking Olympic rings with Mathematica? (SVG version) Edit

Hard choice, but some pretty cool answers here. I didn’t have 3D answers in mind when I posted the question, but ...

asked by Mike Honeychurch https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=77 44 votes

answered by cormullion https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61 23 votes

Calling Correct Function for Plotting DiracDelta

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3506

I am wondering what is the correct function in Mathematica to plot the true impulse function, better known as the DiracDelta[] function. When using this inside of a ...

asked by night owl https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=116 17 votes

answered by Heike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46 19 votes

How to create effect like Van Gogh’s stroke brush?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39003

I need to apply Van Gogh’s stroke brush effect to a random image Take the following image as an example:

Thank you so much if you could help!

asked by user10495 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10495 34 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 51 votes

Parallel and perpendicular symbol from Mathematica to LaTeX

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=46538

I want to get the following expression from Mathematica to LaTeX:

\[ \begin {bmatrix} E_{\parallel } \\ E_{\perp } \end {bmatrix} \]

I have tried to use inbuilt ’symbol’ character from the special ...

asked by Steve Hatcher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13314 19 votes answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 27 votes

Help find a bright object on Mars!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11819

In today’s news, scientists found a bright object on one of Curiosity’s photos (it’s near the bottom of the picture below). It’s a bit tricky to find - I actually spent quite some time staring at the ...

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 198 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 257 votes

2.7.3 Can you answer these questions?

How can I determine and then plot a confidence bands in QuantilePlot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233931

Does anyone know if its possible to plot a confidence band in QuantilePlot? I haven’t been able to find any documentation for this, or a previous example on here.

asked by Q.P. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27119 3 votes

How to remove the smallest term from asymptotic expansion?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233823

It is well-known that \(e^{-1/x}\sim o(x^n)\) as \(x\to 0^+\) for any \(n\in \mathbb {N}\), thus if I do an asymptotic expansion for a function, say \(f=1/(1-x)+e^{-1/x}\) as \(x\to 0^+\), I expect to receive an ...

asked by user142288 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=59534 5 votes

Solving the following system of integrodifferential equations: speed up of the code

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233726

Consider a system of equations

asked by John Taylor https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41058 1 vote

2.8 Thursday, October 29, 2020

2.8.1 Top new questions this week

Dynamically drag graph vertices

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233409

Is it possible to make a dynamic graph with an ability to drag vertices? In other words let vertices behave like Locators and change its ...

asked by swish https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2490 9 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 13 votes

Display Number with SI prefixes

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233503

I have a number of val = 0.000015783 which represents a current value in Amps. I want to display it with 3 significant digits and with SI prefixes instead of the ...

asked by tobalt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27818 7 votes

answered by creidhne https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41569 6 votes

Understanding the profiler: Is pattern matching/de-structuring expensive?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233388

I was profiling some code and I am trying to understand what the results mean. Suppose we have the very idiomatic,

asked by ITA https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42145 7 votes

How to select the fastest approach for large numerical data computations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233677

I really love the flexibility of Mathematica: there are several ways to perform one task. However, to get the performance of the intense numeric calculation, it can ...

asked by Nam Nguyen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1712 6 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 7 votes

Performance of pure function - Best way to define a function?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233637

In general, to define a function, we often use f[x_]. Another way is to use pure function (full form and shorthand). I want to test the performance of these ...

asked by Nam Nguyen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1712 6 votes

Font style inconsistency on "number sign" (hashtag) and "at symbol"

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233665

Why number sign "#" (known as hashtag symbol on social media) or at sign "@" are not consistent with the ...

asked by azerbajdzan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53172 6 votes

answered by creidhne https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41569 9 votes

Solving a Nonlinear Complementary Problem (plasticity)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233340

I would like to solve the following: given \(t\mapsto \sigma (t)\) and \(E>0\), \(\sigma _y>0\), find \(\epsilon \) such that:

asked by anderstood https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18767 5 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 4 votes

2.8.2 Greatest hits from previous weeks

Crack CAPTCHA using deep learning

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=143691

Deep convolutional neural networks are very good at computer vision related tasks. Optical Character Recognition (OCR) is one important branch of computer vision. In fact, the convolution neural ...

asked by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 87 votes

answered by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 98 votes

Why I get the "Set::write: "Tag Times in is Protected." error?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11868

Why I get the error below with this code:

asked by Aurelius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1669 10 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 13 votes

What do the X and Y axis stand for in the Fourier transform domain?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=85139

In Wolfram Mathematica the function Fourier has the following declaration

Fourier[list]

And after a list is given to the ...

asked by user253956 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=29958 27 votes

answered by Hugh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12558 61 votes

Where can I find examples of good Mathematica programming practice?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18

I consider myself a pretty good Mathematica programmer, but I’m always looking out for ways to either improve my way of doing things in Mathematica, or to see if there’s something nifty that I haven’t ...

asked by J. M.’s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 553 votes

answered by faysou https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66 486 votes

How to calculate scalar curvature Ricci tensor and Christoffel symbols in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8895

I am seeking a convenient and effective way to calculate such geometric quantities. I’ve used packages like TensoriaCalc, but they don’t work at all time. Sometimes,...

asked by Zoe Rowa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1713 40 votes

answered by Yi-Zen Chu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4869 18 votes

How to add a front-end to the free Wolfram Engine?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=198839

https://blog.stephenwolfram.com/2019/05/launching-today-free-wolfram-engine-for-developers/

http://www.wolfram.com/engine/

The Free Wolfram Engine for Developers is available for pre-production ...

asked by Alexey Golyshev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=23402 63 votes

answered by Alexey Golyshev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=23402 53 votes

Plotting Complex Quantity Functions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3458

Trying to plot with complex quantities seems not to work properly in what I want to accomplish. I would like to know if there is a general rule/way of plotting when you have complex counterparts in ...

asked by night owl https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=116 42 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 29 votes

2.8.3 Can you answer these questions?

How to define a derivative of a function at some point?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233672

Consider a function  derivative[x_]:=D[Sin[x],x]

When calling it with some argument, like derivative[2], instead of \(\cos (x)\) it gives me \(\partial _{2}\sin (2)\). Is ...

asked by John Taylor https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41058 1 vote

Insufficient memory problem in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233470

I am trying to initialize a 48600 x 48600 packed array from a sparse matrix and a diagonal matrix in Mathematica 8. If S1 is a sparsearray of that size then and S2 is list of 48600 length, then I am ...

asked by Roopayan Ghosh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=54433 4 votes

Classify; how UtilityFunction matrix is applied to resolve prediction?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233669

I can’t find any explanation about the details of the real computation, please anybody knows?

asked by pablo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61453 1 vote

2.9 Thursday, October 22, 2020

2.9.1 Top new questions this week

How can I reproduce this mandala with Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233050

I found this image on the Internet and it is very beautiful. How can I reproduce it? The ideal would be to be able to control the colors of the outside as well as the center.

asked by Susana https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=37778 12 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 32 votes

Tennis Racket theorem

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=232976

Torque-free Euler equations experiment seen in low gravity of Russian spacecraft is modelled here with a view to see its tumbling motion around the intermediate axis \(\omega _2\) rotation. However its ...

asked by Narasimham https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19067 10 votes

answered by Alex Trounev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58388 16 votes

Climbing/Descending the Integer Ladder

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233096

A fun combinatoric puzzle that’s popped up in my work that I think would be cute to have a Mathematica solution to, if anyone wants to give it a go. It’s basically a ladder climbing/descending problem ...

asked by b3m2a1 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38205 8 votes

answered by Leonid Shifrin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=81 5 votes

Remove inner brackets

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233206

If I have the result

asked by GlomGive https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75305 7 votes

answered by wuyudi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68689 10 votes

Identify the Vertices and Lines around the edges of a free surface - Mesh/DiscreteGraphics

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=232975

To write a mesher that closes a mesh surface using an implied surface from a boundary spline curve and mesh generated using DiscreteGraphics, I need to identify the Vertices and Lines around the edges ...

asked by mh2000 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57215 7 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 8 votes

How can I extract the edge points from an image?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233092

I want to extract the edge points from a text image and use ListPlot[points] to visualize those points:

I tried to used ...

asked by vito https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=30288 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

How to speed up integers finding function?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=232960

Playing with integers I looked for a way of finding, let’s say, \(4\)-digits positive integers such that \(a,b,a+b\) had the same digits, like \[1089 + 8019 = 9108\] I am a newbie and I used this function

asked by Raffaele https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=49764 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 12 votes

2.9.2 Greatest hits from previous weeks

Where can I find examples of good Mathematica programming practice?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18

I consider myself a pretty good Mathematica programmer, but I’m always looking out for ways to either improve my way of doing things in Mathematica, or to see if there’s something nifty that I haven’t ...

asked by J. M.’s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 553 votes

answered by faysou https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66 486 votes

Plotting a Phase Portrait

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=14160

I’m trying to plot a phase portrait for the differential equation \[x'' - (1 - x^2) x' + x = 0.5 \cos (1.1 t)\,.\] The primes are derivatives with respect to \(t\). I’ve reduced this second order ODE to ...

asked by covertbob https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4528 38 votes

answered by David Slater https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1746 33 votes

How can I save both the plot and the legend together?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=35653

In this example, how can I put the legend inside the graph? Currently, when I save the graph, only the graph is saved, not the legend.

asked by Mika Ike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6543 42 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 38 votes

Find eigen energies of time-independent Schrödinger equation

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=32293

I’m trying to get the eigenvalues of a one dimensional time-independent Schrödinger equation,

\(-\frac {h^2}{2m_0}\frac {d^2\psi }{dx^2}+U(x)~\psi =Ei~\psi \)

where U(x) is some potential and Ei is the ...

asked by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 48 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 46 votes

xkcd-style Plots

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11350

I received an email to which I wanted to respond with a xkcd-style graph, but I couldn’t manage it. Everything I drew looked perfect, and I don’t have enough command over ...

asked by Amatya https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2039 616 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 474 votes

How to create a new "person curve"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=17704

Wolfram|Alpha has a whole collection of parametric curves that create images of famous people. To see them, enter WolframAlpha["person curve"] into a Mathematica ...

asked by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 83 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 45 votes

How to plot an ellipse?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=20100

I’m new to Mathematica, and I’m finding it difficult to plot an ellipse. I tried using

Plot[(x/5)^2 + (y/3)^2 == 1, {x, -5, 5}, {y, -3, 3}]

but I’m getting ...

asked by Sriram https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6075 17 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 29 votes

2.9.3 Can you answer these questions?

Equation of Motion: Perturb Scalar Field and flat FLRW Metric (xAct)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233105

Is there a way to get the equations of motion (eom) of a scalar field from a Lagrangian in a perturbed FLRW metric? I want to perturb the field as well as the metric to 1st order. What I did so far:

asked by kalle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68748 1 vote

Is there any way to change the box-formatting behavior thoroughly?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233100

Background The box-formmating behavior is affected by the downvalues of the symbol MakeBoxes. But the formatting behavior is not exactly ...

asked by asd1dsa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72876 2 votes

How to get colors at points in Graphics3D?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233287

To get the color at a 2D point in Graphics you can Rasterize it and look up the pixel value, but not for ...

asked by M.R. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=403 2 votes

2.10 Thursday, October 15, 2020

2.10.1 Top new questions this week

How can I plot my financial indicator below a trading chart (produced by TradingChart) with the same x-axis?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=231660

Since this question was not answered, I would like to ask again with some additional information. I have a trading chart saved as chart1 as follows.

asked by DLT https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=54107 9 votes

answered by Lukas Lang https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36508 6 votes

Adding elements of second list in succession

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=231695 Given

t1 = {{1, 2}, {3, 4}}; 
t2 = {{a, b, c}, {e, f}};

I want to add in succession elements of list 2 to list 1 to get:

asked by user57467 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57467 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 8 votes

Has the Undo command really been settled? On version 12.1 it only works sporadically. What are some reasons it drops steps?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=231523

Although Undo has been around since version 10 (before my time) I’ve noticed that sometimes it works just fine up to the moment of the last ...

asked by Jules Manson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=37721 7 votes

Solving heat equation on a cylinder with insulated ends and convective boundary conditions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=231588

I am trying to solve heat equation on a cylinder whose ends are thermally insulated and its circular face is exposed to convection. Therefore I have Neumann boundary condition on all faces of the ...

asked by Deep https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44615 7 votes

answered by yawnoc https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72028 5 votes

Converting a RawBoxes object to a workable expression

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=232789

I have manged to turn an image into a RawBoxes expression. How do I turn in back into something I can use in Graphics In ...

asked by Hugh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12558 6 votes

answered by Carl Woll https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45431 9 votes

Mean age of people

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=232809

I have the following datas:

I want to find mean age by using following formula,

Any way to do this in general in Mathematica easily.

asked by Jasmine https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73364 6 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 12 votes

Suggestion bar still causing Kernel crashes?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=232784

On Mathematica 12.1.1, Windows 10. When Suggestions bar is active, entering and evaluating the following crashes the Kernel.

asked by ciao https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11467 6 votes

2.10.2 Greatest hits from previous weeks

How to express trigonometric equation in terms of of given trigonometric function?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=434

How can I express a trigonometric equation / identity in terms of a given trigonometric function?

using following trigonometric identities

asked by Prashant Bhate https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=99 30 votes

answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 37 votes

Elegant operations on matrix rows and columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3069

Question

The Mathematica tutorial has a section ’Basic Matrix Operations’, describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 180 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 60 votes

What do the X and Y axis stand for in the Fourier transform domain?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=85139

In Wolfram Mathematica the function Fourier has the following declaration

Fourier[list]

And after a list is given to the ...

asked by user253956 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=29958 27 votes

answered by Hugh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12558 61 votes

Figuring when the minute and hour hand coincide on a clock

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=573

I would like to list all possible times in a 12-hour period, where the hour hand overlaps the minute hand completely. This is really a question about three distinct things - to be done in Mathematica ...

asked by Steve D https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=191 15 votes

answered by Verbeia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8 21 votes

Code that generates a mandala

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=136974

My little brother asked me to print original mandalas for coloring. I would like some idea on how to create them, but without color, so he can color them.

examples

asked by zeros https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26849 72 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 95 votes

How to generate a random snowflake

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39361

’Tis the season...

And it’s about time I posed my first question on Mathematica Stack Exchange. So, here’s an holiday quest for you Graphics (and P-Chem?) gurus.

What is your best code for generating ...

asked by Peltio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6745 140 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 181 votes

Extract real part of a complex expression better than Re does

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3306

I have a complex expression with real positive variables only.

Mathematica Input Style:

asked by max https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=796 33 votes

answered by nixeagle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=814 52 votes

2.10.3 Can you answer these questions?

Passing input from a textfile into a function

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=231540

I have a text file which is a list of numbers and would like to pass each number in the list as input to a Mathematica function. For example, my text might contain [2, 1, 4], and I would like to pass ...

asked by Joshua Steier https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75099 1 vote

How to get the coefficients of second-order Runge-Kutta formula coherently?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=231528

The form of the second order Runge Kutta formula is as follows(the following is from page 287 of this book):

asked by A little mouse on the pampas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 1 vote

Taking "intermediate" limits, e.g. \({\cal X}\to 0\) but \({\cal X}/\epsilon \to \infty \) as \(\epsilon \to 0\) - *without* taking \(\epsilon \to 0\) directly

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=232859 I have an expression that I would like to take limits of but not in a conventional sense. Take for example, an expression like

This expression involves intermediate variables

asked by epsilonD3LT4 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75082 1 vote

2.11 Thursday, October 1, 2020

2.11.1 Top new questions this week

What is a good way of perfoming operations on specified columns of a table with many columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230854

If I have a table of data and I want to do a specific operation on say the third column, I usually do something like this:

asked by Q.P. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27119 11 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 8 votes

Quickest way to test whether array is constant

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230971

At the moment I use Length[ DeleteDuplicates[ array ] ] == 1 to check whether an array is constant, but I’m not sure whether this is optimal. What would be the ...

asked by Gert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27889 11 votes

answered by Sjoerd Smit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=43522 9 votes

Solving a rotating combination lock puzzle

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230749

The following puzzle appears in The House of da Vinci II and I thought it might be interesting to tackle in Mathematica:

There are numbers marked on four rotating cylinders. These numbers must add up ...

asked by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 9 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 8 votes

Shortest way to make a checkerboard pattern

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230988

I’m looking for the shortest (in terms of characters) code snippet to make an n-square checkerboard. Here’s my first try (comes in at 72 characters):

asked by M.R. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=403 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

Smoothing the Region?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230725

There is a 2D Pi

I successed transformed it to 3D.

asked by partida https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=15961 7 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 9 votes

How to replace only the isolated variable x?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230717

I want to replace the variable x in the result, not x in unrelated x[i]

asked by A little mouse on the pampas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 11 votes

Counting Elements in Multiple Lists

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230864

How to build a table that counts how many times each element in mainlist occurs in lst1, lst2, lst3, lst4 and which lst1, lst2, lst3, lst4 contains that element. For example, in mainlist, element ...

asked by PRG https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42700 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

2.11.2 Greatest hits from previous weeks

What does # mean in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19035

I asked Mathematica to compute the following

Solve[c (1-x)^2-x^(1/4) == 0, x] 
 
and it returned this: 
  x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 c^4 ...

asked by ronanymous https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5730 37 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 64 votes

Where can I find examples of good Mathematica programming practice?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18

I consider myself a pretty good Mathematica programmer, but I’m always looking out for ways to either improve my way of doing things in Mathematica, or to see if there’s something nifty that I haven’t ...

asked by J. M.’s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 550 votes

answered by faysou https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66 484 votes

How do I identify the source of a "Tag times protected" error?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11982

I have some code that looks like

Table[ 
    a = 1; 
    b = {2, 3} 
    c = i;, 
    {i, 2} 
] 
 
which gives an error: 
  Set::write: Tag Times in c {2,3} is Protected....

asked by dearN https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=204 28 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 35 votes

How to create a new "person curve"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=17704

Wolfram|Alpha has a whole collection of parametric curves that create images of famous people. To see them, enter WolframAlpha["person curve"] into a Mathematica ...

asked by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 83 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 45 votes

Mathematica 10.0.x freezes in Initializing kernels

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=92931

Bug caused by paclet update and fixed by paclet update.

I updated to Windows 10 and have been running Mathematica fine on it for over a month. For some reason, it has just stopped working. I don’t ...

asked by mitcheljh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6783 80 votes

answered by ilian https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=145 101 votes

Extract real part of a complex expression better than Re does

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3306

I have a complex expression with real positive variables only.

Mathematica Input Style:

asked by max https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=796 33 votes

answered by nixeagle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=814 52 votes

Calculate the 2D Fourier transform of an Image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=29203

I am new to Mathematica, and using version 8.0.

I would like to calculate the 2D Fourier Transform of an Image with Mathematica and plot the magnitude and phase ...

asked by user8727 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8727 15 votes

answered by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 32 votes

2.11.3 Can you answer these questions?

Simplify Equation with variable unequal to zero

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230846

How can I simplify the following equation with Mathematica assuming z!=0? I have the following code:

asked by Franz Ferdinand https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74882 1 vote

finding primes using chebyshev bias

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230943

Using the problem from my previous question link. For each n, that is n= \(10^3\) to \(10^6\) with a ten-fold increase, how do I use Chebyshev Bias to display the number of primes (which are in the ...

asked by complab56 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74866 1 vote

Why does NDSolve not give consistent results?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230784

This is my code:

asked by S.J.E. Huisman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74858 1 vote

2.12 Thursday, September 24, 2020

2.12.1 Top new questions this week

Solving the Lotka-McKendrick model with NDSolve

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230366

The Lotka-McKendrick model is a demographic model that represents the way a population changes over time due to fertility and mortality. For an age-specific population density \( u(a, t) \), and a total ...

asked by Pillsy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=531 12 votes

answered by Chris K https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6358 9 votes

Nonlinear dispersal equation modeling insect aggregation

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230429

I’m a newbie with Mathematica, I know it’s a basic answer, but I can’t solve the problem on my own. I have the following equation reflecting insect aggregation at low population densities (taken from ...

asked by Vefhug https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74729 10 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 17 votes

Making a faster alternative for PatternSequence

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230622

I need to improve a pattern or switch an approach. It is best described by an example For a hierarchy/order given by a list e.g.:

order = {1, 2, 3}

and a list:

asked by Kuba https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5478 9 votes

answered by Leonid Shifrin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=81 9 votes

How can I get material property data past what’s provided via ElementData?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230484

Background Let’s say I want information (e.g. bulk modulus or space group) on an element or chemical compound that isn’t available via e.g. ElementData[]

asked by Sterling https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61736 6 votes

answered by Sterling https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61736 6 votes

DSolve does not return solution to simple system of second order PDEs

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230383

I’m trying to solve a simple system of second order PDEs with Mathematica 11.1. Here is the system:

asked by C. B. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74734 6 votes

answered by bbgodfrey https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1063 3 votes

Build the following symmetric array

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230650

My mind is a bit cloudy and I can’t quite pinpoint the pattern here that will allow me to write an elegant piece of code to build the following symmetric matrix of for a given size ...

asked by QuantumDot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2048 5 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 4 votes

Evaluate section by button click

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230613

I have a section in my notebook devoted to unit testing, since I’m not comfortable to use the built-in system. I’d like to evaluate the entire section by button click. But I get lost in the notebook ...

asked by infinitezero https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=31036 5 votes

answered by Kuba https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5478 5 votes

2.12.2 Greatest hits from previous weeks

Assign the results from a Solve to variable(s)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=6669

I understand Mathematica can’t assign the results of a Solve to the unknowns because there may be more than 1 solution. How can I assign the 4 values of following result to variables?

asked by stevenvh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1450 56 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 34 votes

Finding unit tangent, normal, and binormal vectors for a given r(t)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18598

For my Calc III class, I need to find \(T(t), N(t)\), and \(B(t)\) for \(t=1, 2\), and \(-1\), given \(r(t)=\{t,t^2,t^3\}\).

I’ve got Mathematica, but I’ve never used it before and I’m not sure how to coerce ...

asked by a98 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5605 30 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 43 votes

Multivariable Taylor expansion does not work as expected

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=15023

The basic multivariable Taylor expansion formula around a point is as follows:

\[ f(\mathbf r + \mathbf a) = f(\mathbf r) + (\mathbf a \cdot \nabla )f(\mathbf r) + \frac {1}{2!}(\mathbf a \cdot \nabla ) \]

asked by matheorem https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4742 58 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 65 votes

xkcd-style Plots

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11350

I received an email to which I wanted to respond with a xkcd-style graph, but I couldn’t manage it. Everything I drew looked perfect, and I don’t have enough command over ...

asked by Amatya https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2039 615 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 474 votes

What’s the most difficult multidimensional integral that Mathematica has solved?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222184

I am interested in benchmarking numerical integration methods and am trying to develop a wider set of difficult multivariate examples. For my particular methods, I only want to look at non-negative-...

asked by ben18785 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19278 6 votes

Drawing a square root spiral

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66969

Here is a start. I’m looking for a nice way to draw it.

asked by matrix89 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5379 24 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 21 votes

Get a "step-by-step" evaluation in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=148

Is it possible in Mathematica to get a step-by-step evaluation of some functions; that’s to say, outputting not only the result but all the stages that have led to it? If so, how does one do it?

asked by Cydonia7 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44 125 votes

answered by J. M.’s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 105 votes

2.12.3 Can you answer these questions?

How can I make NDSolve aware of vectorial nature of an ODE?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230550

I am trying to solve the equilibrium equation \(\text {DIV } \mathbf P(\textbf {u}(x,y)) = \mathbf {f}\), where \(\mathbf P\) is the stress tensor defined by \[ \mathbf P = \mathbf F + (1-\det \mathbf F) \] asked by rmk236 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74782 1 vote

NDsolve Boundary Condition is a Function of the Solution

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230520

I am trying to solve something like Fick’s Law using NDSolve

\[\frac {\partial \varphi }{\partial t}=\frac {\partial ^2 \varphi }{\partial r^2}+F(r,t)\] Subject to a ...

asked by UranylTrioxide https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74775 1 vote

Optimizing a graph-theoretic piece of code

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230425

I have written the following piece of code:

asked by Mr. Mister https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74745 2 votes

2.13 Thursday, September 17, 2020

2.13.1 Top new questions this week

Display hexagon grid to visualize Langton’s ant

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230017

I am looking to recreate the following image from this reference as

using Mathematica’s Polygon documentation under "Applications" as a starting point. I want to eventually use Mathematica ...

asked by C. Fuhrman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=60593 10 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 8 votes

Position function error

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230018

I recently upgraded from Mathematica 6 to the most recent version. In my new version the Position function returns strange results that were not present in the old ...

asked by Peter https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74626 8 votes

answered by ciao https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11467 11 votes

Mathematica 12.1.0.0 exporting low quality images at high ImageResolution

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229973

I recently upgraded from Mathematica 11 to Mathematica 12.1.0.0 . I understand there were some UI changes to accommodate high resolution monitors. I’m not sure if this issue is related to that. I am ...

asked by user3556814 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74618 8 votes

answered by Piotr Wendykier https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9239 1 vote

How can I count the color pixels in each partition of the image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230060

I have a image of 1000 x 1000 pixels of which I have made 5 x 5 partitions. After that I am looking for a way to count number of color pixels in each partition. Thanks in advance for help.

asked by Atique Khan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=59972 7 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 4 votes

Why does Nearest not return both equally distant values?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230082

Define the following three vectors:

a = {0., 0., 0.}; 
b = {-0.5`, 0.4330127018922193`, 0.25`}; 
c = {-0.5`, 0.`, 0.`};

Note that the distance from a to c is the ...

asked by abwatson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1709 7 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 5 votes

BarChart does not display asymmetric error bars correctly

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230145

BarChart seems to read the uncertainty in elements the other way around. The object: Around[5, {1, 10}] is evaluated as . However, when you use it in a BarChart, the uncertainties are swapped:

asked by Luis https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=24933 6 votes

Pattern-matching complex numbers as a + bi

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230013

I just started working with Mathematica and am toying with pattern matching. There may be something obvious I’m missing in this, but I can’t figure it out by myself. I want to write down a function ...

asked by ppln https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69266 6 votes

answered by eyorble https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=52935 5 votes

2.13.2 Greatest hits from previous weeks

Plot, extract data to a file

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19859

I need to save data that Mathematica uses inside the Plot command. The format that I would like to have is:

x1 y1 
x2 y2 
.....

asked by molkee https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5097 30 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 47 votes

How to calculate scalar curvature Ricci tensor and Christoffel symbols in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8895

I am seeking a convenient and effective way to calculate such geometric quantities. I’ve used packages like TensoriaCalc, but they don’t work at all time. Sometimes,...

asked by Zoe Rowa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1713 38 votes

answered by Yi-Zen Chu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4869 18 votes

How can I improve Mathematica’s resolution on a macbook retina display?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18419

Mathematica 9.0 looks a bit fuzzy on the retina screen, how can I increase the resolution? Here another screenshot showing a direct comparison between the browser and Mathematica

asked by Tom Wellington https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2437 44 votes

Code that generates a mandala

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=136974

My little brother asked me to print original mandalas for coloring. I would like some idea on how to create them, but without color, so he can color them.

examples

asked by zeros https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26849 71 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 95 votes

How to create effect like Van Gogh’s stroke brush?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39003

I need to apply Van Gogh’s stroke brush effect to a random image Take the following image as an example:

Thank you so much if you could help!

asked by user10495 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10495 34 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 51 votes

Find eigen energies of time-independent Schrödinger equation

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=32293

I’m trying to get the eigenvalues of a one dimensional time-independent Schrödinger equation,

\(-\frac {h^2}{2m_0}\frac {d^2\psi }{dx^2}+U(x)~\psi =Ei~\psi \)

where \(U(x)\) is some potential and Ei is the ...

asked by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 48 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 46 votes

How to find the position of elements in a list satisfying criteria

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=180

Say I have a list x={2,4,6,8,10} and I want to find out the positions of the elements that are greater than 7.

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 66 votes

answered by J. M.’s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 63 votes

2.13.3 Can you answer these questions?

Faster alternative to ImageCorrespondingPoints?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229962

I’m trying to use ImageCorrespondingPoints to register frames in a video sequence. Computational speed is an important consideration for the application I am ...

asked by Brady Hunt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9017 2 votes

How to make this expression?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230052

How to code this expression in WolframAlpha. I am interested in how to code the second sum, because it contains a boolean expression: \[\sum _{i=1}^{100}{\sum _{j>n}}{x_{i}x_{j}}\]

asked by Andrey Stebenkov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74632 1 vote

2.14 Thursday, September 10, 2020

2.14.1 Top new questions this week

Can we use Mathematica to design an electronic active filter?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229714

How can we use Mathematica to design an electronic implementation of an active filter?

asked by David Keith https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44700 19 votes

answered by David Keith https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44700 22 votes

How to mesh a French biscuit (modulated ellipsoid)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229535

I would like to create a boundary mesh of the following ellipsoid, whose thickness is modulated along its long axis:

The surface parametrization I used for it is:

asked by Oscillon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13605 10 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 10 votes

Solutions for searching over Mathematica notebooks?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229522

I have hundreds of Mathematica notebooks accumulated over the years, and I’d like to search over them. I’ve been using various versions of text search (grep, SilverSearcher, Spotlight), but there are ...

asked by Yaroslav Bulatov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=217 10 votes

answered by Chris Degnen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=363 11 votes

Coordinate-free derivative

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229703

Given the function \[f:v\mapsto \dfrac {v}{\|v\|},\] I would like to compute the derivative of \(f\), that is \(df(v)\). It is possible to derive it by hand, which leads to

asked by anderstood https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18767 9 votes

Please explain this syntax: GaborWavelet[6]["FourierFactor"]

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229853

I’ve been using Mathematica for some years, yet I’m befuddled by this statement: GaborWavelet[6]["FourierFactor"]

It appears to give the center frequency ...

asked by Chris https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66733 7 votes

answered by Carl Woll https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45431 11 votes

How to select several columns from a dataset

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229678

I have a dataset with 20 columns. For a analysis I need all columns except the columns 9 and 11. What I do is:

asked by Michiel van Mens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9590 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

BarLegend ticks distorted in MatrixPlot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229502

As shown in many threads here (this, this, ...), Ticks is a valid option of BarLegend.

But it doesn’t seem to work well in this ...

asked by xiaohuamao https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11125 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 8 votes

2.14.2 Greatest hits from previous weeks

Help find a bright object on Mars!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11819

In today’s news, scientists found a bright object on one of Curiosity’s photos (it’s near the bottom of the picture below). It’s a bit tricky to find - I actually spent quite some time staring at the ...

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 198 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 257 votes

Extract real part of a complex expression better than Re does

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3306

I have a complex expression with real positive variables only.

Mathematica Input Style:

asked by max https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=796 33 votes

answered by nixeagle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=814 52 votes

Solving \(L=\frac {3}{2} \sqrt {4 \pi ^2 A^2+W^2}-\frac {\sqrt {5 W \sqrt {4 \pi ^2 A^2+W^2}+6 \pi ^2 A^2+3 W^2}}{\sqrt {2}}+\frac {3 W}{2}\) for \(W\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=57763

When I solve the aforementioned equation for \(W\) or \(A\) on Mathematica I get a long and ugly equation in return, namely one of the solutions for \(W\) is: (attempt to read at your own health)

asked by J.D’Almbert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19257 8 votes

answered by Alexei Boulbitch https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=788 15 votes

How to ask Mathematica to imitate Andy Warhol’s pop-art painting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=59132

I tried to ask Mathematica to imitate Andy Warhol, let it convert a Marilyn Monroe’s portrait so that it looks like Warhol’s world famous pop-art painting.

However, the result shown below is far from ...

asked by Putterboy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=16069 50 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 65 votes

Cutting bagels into linked halves

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=7545

I recently came across this video: Mathematically correct breakfast, which shows how a bagel can be neatly sliced into two identical linked halves. I’d like to try this with Mathematica. Here’s a ...

asked by rm -rf https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5 62 votes

answered by Heike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46 76 votes

How to generate a random snowflake

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39361

’Tis the season... And it’s about time I posed my first question on Mathematica Stack Exchange. So, here’s an holiday quest for you Graphics (and P-Chem?) gurus.

What is your best code for generating ...

asked by Peltio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6745 140 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 181 votes

Finding unit tangent, normal, and binormal vectors for a given r(t)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18598

For my Calc III class, I need to find \(T(t), N(t)\), and \(B(t)\) for \(t=1, 2\), and \(-1\), given \(r(t)=\{t,t^2,t^3\}\).

I’ve got Mathematica, but I’ve never used it before and I’m not sure how to coerce ...

asked by a98 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5605 30 votes

2.14.3 Can you answer these questions?

Solving equations over unknown Domains

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229778

I am trying to solve for what values of some variables make some expressions true; not exactly equations. For a toy example, I am trying to solve for all values of \(x\) that make \(4x\) an Integer.

asked by Matthew Crawford https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=51196 1 vote

Not able to globalize variables from a manipulate expression

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229534

I am attempting to globalize the variables inside of a Manipulate expression for which my variables are also using interdependent controls. I have attempted to use

asked by Ryan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74490 1 vote

force maximum simplification of radicals in a traditional way-How to do it?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229660

this should be simple but I can’t get mathematica to simplify a radical or a set of radicals and express them in the traditional way for example by simplifying this

asked by BeTDa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72885 2 votes

answered by Daniel Huber https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46318 0 votes

2.15 Thursday, September 3, 2020

2.15.1 Top new questions this week

Is it possible to call back to Mathematica when using Python through ExternalEvaluate?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229164

makes it possible to call Python code from Mathematica. The Wolfram Client for Python makes it possible to call Mathematica from Python. When using ...

asked by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 8 votes

answered by Riccardo Di Virgilio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=51868 3 votes

Camera view along the trajectory

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229242

I want to create an animation like this one: https://www.youtube.com/watch?v=rvzZmNW2_70 After googling I have found just below informations about this issue: https://twitter.com/bencbartlett/status/...

asked by Mustafa Kosem https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74423 7 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 6 votes

How to select 2 pairs of distinct twins form a list of 4-tuples?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229409

Given a list of 4-tuples as follows. data = Tuples[Range@6, 4]; I want to select any 4-tuples with two pairs of different twins, for example, as follows:

asked by Wissen Macht Frei https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42141 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 3 votes

Combine two plots with reversed y-axis

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229128

I need to display two y-values for a list of points. I tried doing this:

asked by Rodrigo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=43431 6 votes

answered by LouisB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22158 4 votes

Can this probability function speed be improved?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229239

I have a process that as part of it requires a certain probability query, specifically, given a multinomial distribution with f equiprobable categories and r trials, some specific category has a given ...

asked by ciao https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11467 5 votes

answered by JimB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19758 4 votes

Embed a rose flower image in 3D space with axes labeled in UTF8

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229299

I am trying to create an image in which a rose flower image in a 3D space with axes labeled in UTF8! Labels don’t render correctly and not sure how to put the image at say the original of XYZ space.

asked by chikitin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74442 4 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 4 votes

Simplify Nested Lists

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229427

I have a problem with nested lists. For example, i have this list:

asked by aptmess https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58120 4 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

2.15.2 Greatest hits from previous weeks

How can I plot implicit equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=34668

If you enter the following into Wolfram | Alpha, you get nice graphs:

graph 4 x^4 + y^2 = 2  How do you do this in Mathmatica? I realize that these are not ...

asked by Rollie https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10174 36 votes

answered by Timothy Wofford https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9391 38 votes

My Girlfriend is going to prison...Save her with Math

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=135937

Salacious title, but true story.

asked by Prisoners Dilema https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46025 42 votes

answered by bobthechemist https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7167 23 votes

Image processing: Floor plan - detecting rooms’ borders (area) and room names’ texts

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19546

Here is a simple building floor plan. I would like to derive the rooms as (rectangular) components and the names of the rooms. This is very common representation of building floor plans.

The problem

asked by s.s.o https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=840 64 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 59 votes

Crack CAPTCHA using deep learning

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=143691

Deep convolutional neural networks are very good at computer vision related tasks. Optical Character Recognition (OCR) is one important branch of computer vision.

In fact, the convolution neural ...

asked by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 87 votes

answered by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 98 votes

Solving \(L=\frac {3}{2} \sqrt {4 \pi ^2 A^2+W^2}-\frac {\sqrt {5 W \sqrt {4 \pi ^2 A^2+W^2}+6 \pi ^2 A^2+3 W^2}}{\sqrt {2}}+\frac {3 W}{2}\) for \(W\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=57763

When I solve the aforementioned equation for \(W\) or \(A\) on Mathematica I get a long and ugly equation in return, namely one of the solutions for \(W\) is: (attempt to read at your own health)

asked by J.D’Almbert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19257 8 votes

answered by Alexei Boulbitch https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=788 15 votes

Entering numbers in Scientific Notation?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=36792

I need to play with a lot of powers such as 10^-3,1E-3 does not work for it. Is there any short form for it?

asked by hhh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2000 59 votes

answered by Joe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44710 1 vote

Finding unit tangent, normal, and binormal vectors for a given r(t)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18598

For my Calc III class, I need to find \(T(t), N(t)\), and \(B(t)\) for \(t=1, 2\), and \(-1\), given \(r(t)=\{t,t^2,t^3\}\).

I’ve got Mathematica, but I’ve never used it before and I’m not sure how to coerce ...

asked by a98 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5605 30 votes

2.15.3 Can you answer these questions?

How to force FindClusters to return a specific number of clusters?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229313

I am using FindClusters with the Method -> "KMedoids" option. I am specifying a desired number of clusters. It returns with many fewer than the desired number. Is there a way to force it ...

asked by abwatson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1709 2 votes

Calculate a nested integral

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229251

I wish to plot the following probability on Mathematica: \[ \pi =n\cdot \int _{-\infty }^{+\infty }\int _{-\infty }^{+\infty } \]

asked by Avocaddo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68764 1 vote

Differents Initial Conditions for NDSolve

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=229185

I would like to solve a system of differential equations and another euqtions conect to the system. For example:

asked by Slayz https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74408 1 vote

2.16 Thursday, August 20, 2020

2.16.1 Top new questions this week

Deleting duplicates after n-occurrences

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228775

As a generalization of DeleteDuplicates, I want to delete duplicates from a list, but only after n number of duplicates. Say,

asked by azerbajdzan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53172 11 votes

answered by ciao https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11467 16 votes

How can I enclose a closed curve with another identical slightly bigger closed curve?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228524

I have a closed curve. I am trying to enclose this closed curve with another closed curve, which looks identical in the shape of the first closed curve, but slightly bigger. How to do this?

asked by acoustics https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53981 10 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 17 votes

Glowing weighted graph (network): vertexes and edges

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228738

I am trying to find a way (desirably simple and performance/speed optimized for larger graphs) to do the following :

Styling graph vertexes by glow-effect and its intensity depending on ...

asked by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 8 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 5 votes

Why does it take so long to Quit?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228484

Running Quit is a core task repeated many times in any debugging/development cycle. Its efficiency is therefore important and yet in my set-up it is taking ...

asked by Ronald Monson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2249 8 votes

answered by Ronald Monson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2249 9 votes

How to use Flatten to a specific element of a list

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228579

Let's say I have a list {{1, 2, 3}, {4, 5}, ...}. I want to make the list 
look like {1, 2, 3, {4, 5}, ...}. I am doing this way:

asked by Arghya Datta https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=51545 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 10 votes

Parsing error [bug?] with systems of nonlinear PDEs, Mathematica 12.0.0

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228692

I find the following behavior using 12.0.0. (EDIT: I asked a friend to try it in 12.1.1 and he finds the same result.) Here is a system of coupled nonlinear PDEs that ...

asked by Will.Mo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=49788 6 votes

Collecting common powers of terms

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228768

How to collect the common powers appearing in the following function using MATHEMATICA, such that if I input

(4 m^6)/((m - n)^2 (m + n)^4 (2m+n)^4)

then the ...

asked by Erosannin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73763 6 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 3 votes

2.16.2 Greatest hits from previous weeks

Help find a bright object on Mars!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11819

In today’s news, scientists found a bright object on one of Curiosity’s photos (it’s near the bottom of the picture below). It’s a bit tricky to find - I actually spent quite some time staring at the ...

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 198 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 257 votes

How to plot an ellipse?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=20100

I’m new to Mathematica, and I’m finding it difficult to plot an ellipse. I tried using

Plot[(x/5)^2 + (y/3)^2 == 1, {x, -5, 5}, {y, -3, 3}]

but I’m getting ...

asked by Sriram https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6075 17 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 29 votes

How to make the digits of \(\pi \) go around in a spiral like this?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=109982

Here is a start.

MapIndexed[Text[Reverse[First[RealDigits[Pi,10,252]]][[Tr@#2]],#]&, 
 Table[{t Cos[t],t Sin[t]},{t,0,16Pi,0.2}]]//Graphics

asked by matrix89 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5379 56 votes

answered by Martin Ender https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2305 71 votes

How to calculate contour integrals with Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=34073

How to calculate the integral of \(\frac {1}{\sqrt {4 z^2 + 4 z + 3}}\) over the unit circle counterclockwise for each branch of the integrand?

asked by user64494 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7152 40 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 63 votes

How to make a Spherical Cow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=125043

Being a theoretical physicist, I always have a great respect for Spherical Cow. So I thought about making one myself. I am not sure how can I create (something considered to be the simplest!) this ...

asked by Sumit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8070 69 votes

answered by andre314 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5467 76 votes

How to find integer solutions?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=42359

Following is the equation: Need to solve for integer values of x,y when a,b lies between -1000 and 1000. Problem is to find the number of integer values of pair (x,y) that satisfy it.

asked by Sahil Sareen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12396 2 votes

answered by bill s https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1783 4 votes

Plotting a Phase Portrait

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=14160

I’m trying to plot a phase portrait for the differential equation \[x'' - (1 - x^2) x' + x = 0.5 \cos (1.1 t)\,.\] The primes are derivatives with respect to \(t\). I’ve reduced this second order ODE to ...

asked by covertbob https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4528 38 votes

answered by David Slater https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1746 32 votes

2.16.3 Can you answer these questions?

Export function not working via JLink in Java8 compiled application

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228496

I have documented the following issue with evaluating the Export function via J/Link: https://stackoverflow.com/questions/63390977/wolfram-mathematica-kernellink-export-function-not-working-via-jlink- ...

asked by Ceddaerrix https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74211 1 vote

Custom arrowhead will not align properly

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228631

I am trying to put a custom arrowhead on an arrow I am drawing in a plot. My problem is that the (thick) line of the arrow is showing behind the arrow tip. So it seems like the arrowhead is aligned ...

asked by Bjoj https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36437 1 vote

How to control a presenter notebook with a mobile device?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228733

In the video of the link below, at 1:40 is said that the presentation can be controlled by a mobile device, how can I do that?

https://www.youtube.com/watch?v=GMHM_iUL_sU

asked by Daniel Rocha da Silva https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74279 1 vote

2.17 Thursday, August 13, 2020

2.17.1 Top new questions this week

Which function names have been re-purposed in Mathematica after being deprecated?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228295

I have just learned about the new function Splice from this answer. It turns out that this function used to have a completely different usage! (See below.) To me, this seems dangerous, to deprecate a ...

asked by march https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=29734 14 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 9 votes

StringJoin in Thread not working

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228320

Here is what I have tried first.

Thread[f["x", {"1", "2"}]] 
 
{f["x", "1"], f["x", "2"]}

But the weirdest thing happened when I ...

asked by kile https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=65814 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

Using sequence to complete arguments to a function

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228363

I have a function of, say 4 arguments f[a,b,{c,e},d] where some of the arguments are lists. Given a list of triplets that are possible last-three-arguments to f I’d like to paste them as arguments to ...

asked by ulvi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1714 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

How can I get the progressive application of list of rules?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228088

I have a very long list of rules, and using this list of rules I want to see how some elements evolve as I successively apply the next rules on the previous rule.

Here is the simpler version of my ...

asked by Gummala Navneeth https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66938 6 votes

answered by march https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=29734 9 votes

Finding the Period of a Limit Cycle

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228319

I’m interested in the periods of limit cycles of the Wilson-Cowan equations which have the form \[x'(t) = -x + S(ax(t) - by(t) +e)\] \[y'(t) = -y + S(cx(t) - dy(t) + f)\] where \[S(x) = 1 + \] ...

asked by Cheyne https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74162 5 votes

answered by Chris K https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6358 6 votes

Assigning a Color to each Point on the Plane

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228423

I have a dataset consisting of points on the plane and a corresponding color. These colors divide the plane into a few distinct regions. I would like to make a plot or diagram that nicely shows this ...

asked by Cheyne https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74162 5 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 4 votes

using regex to find a specific word

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228278

I want to find the word "circle" and "circles" in the list.

list = {"circle" , "picircle" , "circles" }

The regex code I wrote which isn’t working:

asked by Aryan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73776 5 votes

answered by Natas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=67431 7 votes

2.17.2 Greatest hits from previous weeks

Can Mathematica do symbolic linear algebra?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3242

For instance, is there some way I can say "let A and B be arbitrary real \(m\times n\) and \(k\times m\) matrices, Simplify[Transpose[Transpose[A].Transpose[B]]]" and Mathematica would simplify it to B.A? ...

asked by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 63 votes

answered by Chip Hurst https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4346 6 votes

How to make the digits of go around in a spiral like this?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=109982

Here is a start.

MapIndexed[Text[Reverse[First[RealDigits[Pi,10,252]]][[Tr@#2]],#]&, 
 Table[{t Cos[t],t Sin[t]},{t,0,16Pi,0.2}]]//Graphics

asked by matrix89 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5379 56 votes

answered by Martin Ender https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2305 71 votes

How to plot an ellipse?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=20100

I’m new to Mathematica, and I’m finding it difficult to plot an ellipse. I tried using

Plot[(x/5)^2 + (y/3)^2 == 1, {x, -5, 5}, {y, -3, 3}]

but I’m getting some errors. Is there something wrong ...

asked by Sriram https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6075 17 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 29 votes

Standard deck of 52 playing cards in curated data?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=16108

I am not sure how to find out what all is included as curated data. For example, are the individual images of each of the 52 cards in a standard deck of playing cards included?

If not, is there a way ...

asked by JohnD https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1629 25 votes

answered by rm -rf https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5 23 votes

Skip header lines on import

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=50718

When importing a data file what are the comment symbols for Mathematica? That is, given a file like this

blabla 
bulbul 
 
1 2 6 54 7 ... 
..

what symbol do I have to put in front of header lines so ...

asked by MaxJ https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=14687 20 votes

answered by george2079 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2079 18 votes

How to graph a sphere with cartesian equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=24169

I’m new to Mathematica and I need to ask how to graph a sphere, cylinder, etc.. using cartesian equations.

For example in sphere’s case \(x^2+y^2+z^2=1\)

I tried to use Plot3D but it doesn’t ...

asked by German https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7145 7 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 13 votes

How to create a new "person curve"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=17704

Wolfram|Alpha has a whole collection of parametric curves that create images of famous people. To see them, enter WolframAlpha["person curve"] into a Mathematica notebook, or person curve into ...

asked by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 83 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 45 votes

2.17.3 Can you answer these questions?

Mathematica 12.0 and BibTeX reference problem (Windows 10)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228347

I have problems getting the Citation Management in Mathematica 12.0 to work. It does not work with either EndNote or BibTeX. To do a minimal example, I have the following BibTeX file (libra.bib) ...

asked by jaclea https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7911 1 vote

How to convince Mathematica that \((-1)^{2/3} = e^{2\pi i /3}\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228257

I have a list T which contains 3 + 4*E^(2*Pi*I/3). Yet MemberQ[ T , 3 + 4*(-1)^(2/3) ] 
returns false. 
One can check for themselves with MemberQ[{3 + 4*E^(2*Pi*I/3)}, 3 + 4*(-1)^(2/3)]. 
It will return  ...

asked by Descartes Before the Horse https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69355 2 votes

How to monitor progress of multiple downloads with URLDownload?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228403

I have a few image urls that I want to download async, how can we monitor progress of URLDownload? Example:

Monitor[ 
    URLDownload[ 
         WebImageSearch["dog",  ...

asked by M.R. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=403 1 vote

2.18 Thursday, August 6, 2020

2.18.1 Top new questions this week

How can I find a functional square root in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227863

A functional square root of a function \(g\) is another function \(f\) such that \(g=f\circ f\). According to that article, there is a systematic approach to finding a functional square root that involves ...

asked by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 10 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 2 votes

The numerics of FresnelS[]

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227893

Bug introduced in 12.1 or earlier and persisting through 12.1.1 or later [CASE:4615361]

Note: A worse problem existed in 12.0 for inputs greater than 8 and of precisions less than 43.66; 12.1 fixed ...

asked by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 9 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 6 votes

How to enter a nuclear reaction?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227846

Sometimes the simplest things are the most difficult, I need to make a presentation, and I thought to do it in Mathematica, I wanted to do a demonstration too, well...this is the Rutherford’s equation

asked by Chris Schwenke https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=65367 9 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 14 votes

How to find a numerical antiderivative with NIntegrate methods?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227869

@JimBelk asked in Interpolating an Antiderivative how to find a numerical antiderivative. I gave an answer that uses NDSolve with the default method for integrating \(y'=f(x,y)\). However for ...

asked by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 8 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 9 votes

How to draw one-line Venn diagram?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227990

This is the a list of set.

data = {{"A"}, {"J"}, {"Q"}, {"G", "H"}, {"I", "O"}, 
  {"B", "C", "E",  ...

asked by partida https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=15961 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 10 votes

How to express permutation as the least number of exchanges

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227996

If there are grammatical or terminological errors in the following description, please help correct:

In some problems, it is necessary to find out what minimum number of exchanges can change a list ...

asked by Ordinary users68 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 5 votes

answered by Hausdorff https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73380 5 votes

Remove mesh triangles in contour plot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227837

How do I get rid of the mesh in this contour plot?

 ContourPlot[x^2 + y^2, {x, -10, 10}, {y, -10, 10}, 
    Contours -> {1.0, 4.0, 10.5}, ContourStyle -> None, 
    ContourShading ->  ...

asked by QuantumDot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2048 5 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 6 votes

2.18.2 Greatest hits from previous weeks

How to create animated snowfall?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=16881

Well, the title is self-explanatory. What sorts of snowfall can we generate using Mathematica? There are two options I suggest to consider:

1) Continuous GIF animations with smallest possible number ...

asked by faleichik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=219 39 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 53 votes

What does # mean in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19035

I asked Mathematica to compute the following

Solve[c (1-x)^2-x^(1/4) == 0, x] 
 
and it returned this: 
 
  x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 c^4 + 70 #1^4 c^4 - 56 #1^3 c^4 + 28  ...

asked by ronanymous https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5730 37 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 63 votes

Elegant operations on matrix rows and columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3069

Question

The Mathematica tutorial has a section ’Basic Matrix Operations’, describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 179 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 60 votes

Help find a bright object on Mars!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11819

In today’s news, scientists found a bright object on one of Curiosity’s photos (it’s near the bottom of the picture below). It’s a bit tricky to find - I actually spent quite some time staring at the ...

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 198 votes answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 257 votes

Plot, extract data to a file

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19859

I need to save data that Mathematica uses inside the Plot command. The format that I would like to have is:

x1 y1 
x2 y2

i.e. basically, two columns, x and y (sorted, if possible) so that I ...

asked by molkee https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5097 29 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 46 votes

Labeling individual curves in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=4444

I need to create a plot for export and inclusion in a report. Is there a better way to label curves than PlotLegends? From what I’ve read and my personal experience, PlotLegends is pretty bad.

Is ...

asked by Tianxiang Xiong https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1041 62 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 46 votes

How to add a vertical line to a plot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3561

In the plot below I would like to add two vertical lines at \(x = \frac {\pi }{15} \pm \frac {1}{20}\). How can I do that?

f[x_] := (x^2 z)/((x^2 - y^2)^2 + 4 q^2 x^2) /. {y -> /15, z -> 1, q ->  ...

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 56 votes

answered by Ajasja https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=745 76 votes

2.18.3 Can you answer these questions?

Does MMA have a built-in function or a user-defined function to judge whether the two matrices are congruent

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227756

It can be seen from the following relationship that matrix A and matrix B must be congruent matrices with each other:

A = {{1, 4, 4}, {5, 2, 2}, {3, 1, 3}}; 
B = EulerMatrix[{/4, 0,  ...

asked by Ordinary users68 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 3 votes

Symbolic solution to periodic boundary conditions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=228028

Is it possible to get an analytical solution to the following problem? If so, how? \[a w^{(1,0)}(x,t)+b w^{(0,1)}(x,t)=p(x)+g w(x,t)\]

asked by Scott G https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74062 1 vote

answered by Michael Seifert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27813 0 votes

Collecting terms in NCAlgebra

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227812

Let's say we have GP[v],GM[v]: two noncommutative objects depending on the commutative variable v. 
<< NC`; 
<< NCAlgebra`; 
SetCommutative[v]; 
SetNonCommutative[GP, GM] 
NCCollect[ 
 GM[v] **  ...

asked by Kawette https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=60529 1 vote

2.19 Thursday, July 23, 2020

2.19.1 Top new questions this week

How to rewrite a tensor as a matrix

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226089 I put

{TensorProduct[{1, 0}, {0, 1}, {0, 1}, {0, 1}, {0, 1}]}/Sqrt[2]//MatrixForm 
and I got 
$$ 
\left( 
\begin{array}{cc} 
 \left( 
\begin{array}{cc} 
 \left( 
\begin{array}{cc} 
 0 & 0 \\ 
 0 & 0 \\

asked by Moeki https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73815 12 votes

answered by Suba Thomas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5998 9 votes

Breaking "Functional Loops" and Doing Lazy Evaluation In Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226334

Alright, so this is a question about the functional way to break a for/while loop. Since we’re on the Mathematica SE, I’m interested in the ways a Mathematica vet would handle this, however the ...

asked by dskeletov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34831 8 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 6 votes

Hexadecimal bytes as variable converted to binary bits

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226171

I am working with hexadecimal bytes but need to shift them into lists of binary bits for a few operations and then back again. For example, I would like C12B to turn into ...

asked by toothandsticks https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73837 8 votes

answered by Hausdorff https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73380 9 votes

Kernel starts up very slowly on Linux

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226128

V 12.1.1, starting a kernel, e.g. by entering wolframscript in the shell, takes 
an unexpectedly long time (~5 min, the time elapsed between pressing Enter and 
the showing-up of In[1] := ); but the  ...

asked by https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12924 8 votes

answered by Ordinary users68 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 5 votes

How to decompose a list of n-tuples into a union of Cartesian products

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226294

I have a list with all elements at the same level

{ 
    {a, d}, {a, e}, {a, f}, 
    {b, d}, {b, e}, {b, f}, 
    {c, d}, {c, e}, {c, f}, 
    {x, t}, {x, q} 
}

How can I transform this to a list of ...

asked by Martin Leung https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73880 7 votes

answered by yarchik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9469 4 votes

Mathematica emits a beep after any evaluation - how to remove it?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226316

Without any obvious reason Mathematica started to emit a beep after each evaluation, even when it is error free. Why is that, and how can I turn it off? I tried restarting Mathematica to no avail, and ...

asked by Jxx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68480 6 votes

answered by Ordinary users68 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 6 votes

Prony series with a large number of terms

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226327

A Prony series is similar to a Fourier series but can have fewer terms. It takes the form \(\sum _{i=1}^{M} A_i e^{\sigma _i t} \cos \left (\omega _i t+\phi _i\right )\) Note that unlike Fourier series ...

asked by Hugh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12558 6 votes

2.19.2 Greatest hits from previous weeks

Is there an open source implementation of Mathematica-the-language?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=4454

I’ve seen questions before such as "What is the best open-source equivalent for Mathematica?", but that specific question (and that line of inquiry in general) cares more about the computer algebra ...

asked by sblom https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=178 121 votes

answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 83 votes

Image processing: Floor plan - detecting rooms’ borders (area) and room names’ texts

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19546

Here is a simple building floor plan. I would like to derive the rooms as (rectangular) components and the names of the rooms. This is very common representation of building floor plans.

The ...

asked by s.s.o https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=840 63 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 58 votes

How to make Jacobian automatically in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=5790

If we have two vectors, \(a\) and \(b\), how can I make Jacobian matrix automatically in Mathematica?

$$ a=\left( 
\begin{array}{c} 
 x_1^3+2x_2^2 \\ 
 3x_1^4+7x_2 
\end{array} 
\right);b=\left(

asked by George Mills https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1012 38 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 50 votes

Skip header lines on import

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=50718

When importing a data file what are the comment symbols for Mathematica? That is, given a file like this

blabla bulbul

1 2 6 54 7 ...

what symbol do I have to put in front of header lines so ...

asked by MaxJ https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=14687 20 votes

answered by george2079 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2079 18 votes

How to find the position of elements in a list satisfying criteria

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=180

Say I have a list x=2,4,6,8,10 and I want to find out the positions of the elements that are greater than 7.

Select[x, #>7&] gives the elements themselves, and Position[x,8] gives the  ...

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 65 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 62 votes

How to make an inkblot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3345

How to effectively create a polygon that looks like a realistic inkblot? So far, I could come up with this (borrowing from Ed Pegg Jr.’s Rorschach demonstration):

RandomBlot[num_, opts___] :=  ...

asked by István Zachar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=89 86 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 51 votes

How to generate a random snowflake

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39361

’Tis the season... And it’s about time I posed my first question on Mathematica Stack Exchange. So, here’s an holiday quest for you Graphics (and P-Chem?) gurus.

What is your best code for generating ...

asked by Peltio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6745 140 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 181 votes

2.19.3 Can you answer these questions?

How to write this piece of code without AppendTo

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226081

I am trying to fill a vector starting from component 11 from another vector, I use this code:

Do[AppendTo[xp, x[[i + 10]]], {i, 1, 99982}]

How can I fill xp without using ‘AppendTo’?

asked by mattiav27 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8822 1 vote

Solving a cubic equation in mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226231

I am trying to solve a cubic equation using Mathematica of a rather complicated expression say \(f(r,\beta ,\theta )\) , and in terms of \(r\) the maximum degree term that appears is of degree \(3\) so I ...

asked by Wubba lubba dub dub https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70072 1 vote

Using Select for lattice points

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=226130

I know how to use Select to generate a list of numbers which satisfy a certain condition. However, I am not sure how to do this for points (specifically 2-tuples) rather than numbers. What I am trying ...

asked by Descartes Before the Horse https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69355 1 vote

2.20 Thursday, July 16, 2020

2.20.1 Top new questions this week

Reveal the formal PDE of FiniteElement

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225711

When FiniteElement method is used, the differential equations will first be transformed to certain standard form (named as formal PDE in recent FEM document), and it turns out to be critical to check ...

asked by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 11 votes

answered by user21 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18437 8 votes

Drag and lift force acting on an airfoil

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225928

To calculate force acting on an airfoil we can use FEM with version 12 and over. Here we show an example with NACA2415. First we calculate mesh and potential flow:

ClearAll[NACA2415]; 
NACA2415[{m_,  ...

asked by Alex Trounev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58388 9 votes

answered by user21 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18437 6 votes

When is a symbol a Symbol? Is there an easy mathematica way to test if an object is a symbol sort of like a SymbolQ?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225811

Yes I know there is no built in native function called SymbolQ (but JavaScript does). However could one be simulated to work for most cases? I often rely

on objectName[symbol] and makeRuleRow[symbol]  ...

asked by Jules Manson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=37721 9 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 8 votes

Using Regular Expression

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225910

sample2 = "this is a test to find whether pi works for other words or not as well pi pi pi potatpi pineapple pi-neapple";

so sample2 is a string, and I want to search the word/substring ...

asked by Aryan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73776 8 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 9 votes

Changing the color of the animate box

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225941

Is there a way to change the coloring of the boxes that are generated by Animate or Manipulate? The color of what is gray by default.

Animate[ArrayPlot[CellularAutomaton[n, {{1}, 0}, {40, All}]], {n,  ...

asked by thinkingdude https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73139 8 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

Bad linear fit for simple data

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225985

I have some data :

data={{1.01074, 0.964488}, {1.08552, 0.993067}, {1.07907, 
  1.01836}, {1.0477, 1.03695}, {1.07717, 1.07973}, {1.10243, 
  1.08195}, {1.12669, 1.09112}, {1.09405, 1.09319},  ...

asked by J.A https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58104 7 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 12 votes

How to use each replacement only once in a list of replacements

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225929

I have a list of replacements and some list they are acting on. However, some RHS of the replacements rules are identical (the LHS is not). I want to use those rules one after another (perhaps cycling ...

asked by Kvothe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45020 7 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 5 votes

2.20.2 Greatest hits from previous weeks

Positioning axes labels

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=87388

I need to change the position of my axes labels such that the y-axis label is in the middle and parallel to the y-axis. I’d also like the x-axis label to be in the middle of the x-axis rather than ...

asked by John_dydx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7849 15 votes

answered by Virgil https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27697 16 votes

Generate a Unit Circle Trigonometry

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2456

Struggling often with Trigonometry I would like to have some code to generate this Unit Circle Trigonometry. Would be of great help when I need to transform some data :

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 18 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 32 votes

Is there something like DensityPlot3D to visualize atomic orbitals?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=32378

I’m visualizing some hydrogen like atomic orbitals. For looking at plane slices of the probability density, the DensityPlot function works well, and with something like:

Manipulate[ 
 DensityPlot[  ...

asked by Peeter Joot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10 45 votes

answered by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 24 votes

Mathematica command that allows it to read my intentions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=194384

In version 2.0 of Mathematica there was a command, ReadProgrammerIntentions[ ] which allowed it rapidly compose code that could solve problems simple to complex, based on my requirements. Understand ...

asked by MikeY https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=47314 52 votes

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 38 votes

Does Mathematica 11 work with MacOS Catalina 10.15

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=207522

I just upgraded my macbook to 10.15 and could not open Mathematica 11. I am wondering are there any workarounds to use Mathematica 11 without upgrading to 12? Thank you!

asked by Jiang Xiang https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=16218 27 votes

answered by Itai Seggev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4848 18 votes

Finding Limits in several variables

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=21544

Is there a way to find a limit of a multivariable function, like

\[\lim _{(x,y)\to (0,0)} f(x,y)\] with Mathematica?

When \(f\) is continuous, we can use \[\lim _{(x,y)\to (0,0)}\] ...

asked by Dominic Michaelis https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5899 31 votes

answered by whuber https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=91 42 votes

Parallel and perpendicular symbol from Mathematica to LaTeX

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=46538

I want to get the following expression from Mathematica to LaTeX:

\begin{bmatrix} 
E_{\parallel} \\ E_{\perp} 
\end{bmatrix}

I have tried to use inbuilt ’symbol’ character from the special ...

asked by Steve Hatcher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13314 18 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 26 votes

2.20.3 Can you answer these questions?

Finding the domain in which a function is analytic with no imaginary part

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225913

I was wondering if it is easy to see if a given expression evaluates to a real number in a given domain? Let e.g. \(f(x,y,z)\) be some function depending on three variables \(x,y,z\). I would like to know if ...

asked by CAF https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=30885 1 vote

Argmax - all maximizer positions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225980

Generally the Argmax function returns one position, where a function is maximized. Is there a easy way to obtain a list of rules for all maximizer points?

asked by Daniel Rehsmann https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73792 1 vote

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 0 votes

AceFEM MacOS not responding

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225678

I just upgraded to v7.114 of AceFEM running on MacOS 10.15.5 and Mathematica 12.0.0.0. I was running v7.101 without a problem. AceGEN seems to work but all AceFEM code starts but does nothing. The ...

asked by Andrew https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73727 1 vote

2.21 Thursday, July 9, 2020

2.21.1 Top new questions this week

How to solve the Monty Hall problem?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225238

Problem For purely recreational purposes I would like to solve the Monty Hall problem with Mathematica using the function Probability (dedicated to the calculation of probabilities). About the Monty ...

asked by mlpo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11155 12 votes

answered by Sjoerd Smit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=43522 16 votes

Change Opacity along a ListLinePlot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225337

I’m trying to change the opacity of a line in a ListLinePlot for increasing x-value. E.g. the line should have opacity 1 at beginning and shade than down to opacity along the line. I want to take the ...

asked by piolio https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73660 10 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 8 votes

Use Cases with empty cells in the list

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225360

I work with a complex dataset. The most simple form of this list looks like:

dat1 = {{a, b, c, {}}, {d, e, f, {1}}, {h, i, j, {2}}} 
 
I want to select the nested {} part. 
Cases[dat1, {___, {a_}} :>  ...

asked by Michiel van Mens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9590 9 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 9 votes

Writing compiled functions as fast as Python’s Numba

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225277

I want to write some code to simulate a damped oscillator that is just as fast as code written using Numba's @njit decorator. I’ve written the mathematica code and mine is 20-40x slower than the ...

asked by Diffycue https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46327 9 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 16 votes

Why are more highly nested lists often not more memory and time-intensive?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225540

I would expect more highly nested lists, being deeper and more complex than flatter lists, to take up more space (bytecount) and take more time and memory to operate on in general. Consider the ...

asked by Just Some Old Man https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12697 7 votes

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 10 votes

Correcting the Color Scale of a MatrixPlot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225186

I did a MatrixPlot of a set of values that range between 0 and 1. I got the following first plot with no problems:

As we can see from the legend, the values range between 0 and 1. Now, I am doing ...

asked by Naps https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73570 7 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 5 votes

Verify an inequality of many parameters

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225380

I’ve got an inequality of 10 non-negative parameters (arising from a 5x5 matrix) and would like to verify whether it holds. I tried the following, which doesn’t seem to work:

asked by Vicky https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73675 6 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 4 votes

2.21.2 Greatest hits from previous weeks

How to calculate scalar curvature Ricci tensor and Christoffel symbols in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8895

I am seeking a convenient and effective way to calculate such geometric quantities. I’ve used packages like TensoriaCalc, but they don’t work at all time. Sometimes, I run into the following error:

asked by Zoe Rowa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1713 38 votes

answered by Yi-Zen Chu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4869 18 votes

Figuring when the minute and hour hand coincide on a clock

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=573

I would like to list all possible times in a 12-hour period, where the hour hand overlaps the minute hand completely. This is really a question about three distinct things - to be done in Mathematica ...

asked by Steve D https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=191 15 votes

answered by Verbeia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8 21 votes

xkcd-style Plots

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11350

I received an email to which I wanted to respond with a xkcd-style graph, but I couldn’t manage it. Everything I drew looked perfect, and I don’t have enough command over PlotLegends to have these ...

asked by Amatya https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2039 613 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 472 votes

Are you interested in purchasing David Wagner’s "Power programming with Mathematica"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=16485

I recently contacted McGraw-Hill to see if they have a mechanism in place for printing out-of-print books that are still of interest. Specifically, I asked about "Power programming with Mathematica" ...

asked by Todd Allen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=249 158 votes

answered by Todd Allen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=249 233 votes

Parallel and perpendicular symbol from Mathematica to LaTeX

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=46538

I want to get the following expression from Mathematica to LaTeX:

 
\begin{bmatrix} 
E_{\parallel} \\ E_{\perp} 
\end{bmatrix}

I have tried to use inbuilt ’symbol’ character from the special ...

asked by Steve Hatcher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13314 18 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 26 votes

Mathematica Minecraft

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19669

Some time ago I asked myself: with all these great graphics and interactive capabilities of Mathematica, what kinds of 3D games can be implemented in it? And the answer which came to mind is ...

asked by faleichik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=219 164 votes

answered by faleichik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=219 234 votes

Labeling individual curves in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=4444

I need to create a plot for export and inclusion in a report. Is there a better way to label curves than PlotLegends? From what I’ve read and my personal experience, PlotLegends is pretty bad.

asked by Tianxiang Xiong https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1041 62 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 46 votes

2.21.3 Can you answer these questions?

How to include a meter in Manipulate that shows a value calculated from the manipulate dynamic variable?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225465

I’m trying to make a visualization of grid (representing magnetic states) and I want to include a meter that shows a variable calculated from the manipulate index

(of the form J1/J2 = (index)*0.1) so  ...

asked by mike1994 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73104 1 vote

Measuring the time remaining until completion for built in functions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225436

All of the functions in How to create a progress bar?, the ProgressIndicator built-in and Monitoring lengthy computations estimate the completion time for implementation of operations that are ...

asked by thinkingdude https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73139 1 vote

creating uppertriangularized matrix

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225231

I am trying to create an uppertriangularized matrix of arbitrary size,max of the form

{{1,2,3,4,5},{0,1,2,3,4},{0,0,1,2,3},{0,0,0,1,2},{0,0,0,0,1}} 
 
using the code 
table = Table[mu^(j - 1)  ...

asked by Z Ming Ma https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70345 1 vote

2.22 Thursday, July 2, 2020

2.22.1 Top new questions this week

How to make a structured mesh with a hole and extrude it

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224739

I am trying to use the FEMAddOns package to make a structured mesh with a hole and then extrude it. As a warm up example this worked nicely.

Needs["FEMAddOns`"] 
pts1 = Table[ 
  25. (  ...

asked by Hugh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12558 14 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 13 votes

How to NOT a specific pattern?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225008

been going around in cirlces on this:

{1/3, 1, 0.22, 3, "v", 4} /. _?NumericQ -> "999"

Now I’m trying to replace everything that is not a number; is there a way to do this? ...

asked by CuriousDudeFromEgypt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66462 10 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 13 votes

Ordering Problem With VoronoiMesh

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224830

Imagine I want to model 2D cells moving in a tissue. Consider, as an example, Lloyd’s relaxation algorithm. Using VoronoiMesh I’m able to mimic some cell movement. Now, if I colour one of the cells in ...

asked by sam wolfe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=64001 9 votes

answered by TumbiSapichu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53229 2 votes

Peculiar behaviour in the implementation of "Filling"

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224907

I was working with mathematica and I need to use "Filling", however I notice that it doesn’t work when you have "small" numbers, for example if I make the following:

asked by Cruz https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69573 9 votes

i_:0|1 varies in v12.1: incompatible change or bug?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224987

Just check

i_: 0 | 1 // FullForm 
 
In v12.0 or earlier the output is 
Alternatives[Optional[Pattern[i, Blank[]], 0], 1] 
 
But in v12.1 the output becomes 
Optional[Pattern[i, Blank[]], Alternatives[0,  ...

asked by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 9 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 9 votes

Inverse of StringReplace

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225071

Suppose I have the following StringReplace rule

StringReplace[st, {"a" -> "0", "OverBar[a]" -> "1", "b" -> "1",

asked by math https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72358 8 votes

answered by Suba Thomas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5998 8 votes

Intersection of 3 circles in GeometricScene

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224874

I am trying to represent the image below in Mathematica and can’t seem to make it work. There doesn’t seem to be any constraint of type circle intersection in the documentation. I tried this:

asked by SorinS https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73427 8 votes

answered by SneezeFor16Min https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69875 11 votes

2.22.2 Greatest hits from previous weeks

Why I get the "Set::write: "Tag Times in is Protected." error?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11868

Why I get the error below with this code:

Needs["VectorAnalysis`"] 
 
 = 1000; 
g = 9.80665; 
 = 0.001; 
p[x_, y_, z_, t_] = {x^2, Sqrt[y], -z, t^3}; 
f[x_, y_, z_, t_] = {-x^2, Sqrt[y]/2, z, t^2}; 
 
  ...

asked by Aurelius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1669 10 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 13 votes

What are the most common pitfalls awaiting new users?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18393

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...

asked by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 462 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 279 votes

Is it possible to export the equations from Mathematica to MATLAB?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=14035

Is it possible to export the output expressions from Mathematica computations (e.g., equations) in valid MATLAB syntax?

asked by Seyhmus Güngören https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4256 41 votes

answered by rm -rf https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5 48 votes

Generate a Unit Circle Trigonometry

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2456

Struggling often with Trigonometry I would like to have some code to generate this Unit Circle Trigonometry. Would be of great help when I need to transform some data :

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 18 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 32 votes

How to find the position of elements in a list satisfying criteria

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=180

Say I have a list x=2,4,6,8,10 and I want to find out the positions of the elements that are greater than 7.

Select[x, #>7&] gives the elements themselves, and Position[x,8] gives the  ...

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 64 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 62 votes

Get a "step-by-step" evaluation in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=148

Is it possible in Mathematica to get a step-by-step evaluation of some functions; that’s to say, outputting not only the result but all the stages that have led to it? If so, how does one do it?

asked by Cydonia7 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44 125 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 105 votes

Is there any algorithm that runs faster in Mathematica than in C or Fortran?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=208045

I’m just curious. My friend just told me that Mathematica is mostly for symbolic calculation and not efficient for Numerical computations. He told me that’s the reason most of the people don’t use ...

asked by Gummala Navneeth https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66938 44 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 73 votes

2.22.3 Can you answer these questions?

An apparent bug in Geometry‘ConvexHull2

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224966

I was replacing some usages of Geometry‘ConvexHull2 with ConvexHullMesh and found one of my tests failing. It turned out the test asserted an incorrect expected result that agrees with the result of ...

asked by Vladimir Reshetnikov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7288 1 vote

When making a package, how can I make a function that is already used by system?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224730

Obviously, Plus[a,b] is given by Mathematica but say I have a package and I want to name a function Plus[a,b]. How can I go about making a new function without overwriting the original function ...

asked by Brandon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73362 2 votes

Simplifying expressions using elementary properties of integrals

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=225023

I want to be able to use Simplify (or FullSimplify) to simplify expressions involving, for example, sums of integrals, for instance turning \[ \int _a^b f(x)\,dx + \int _b^c f(x)\,dx \] into \[ \int _a^c\] ...

asked by Pillsy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=531 2 votes

2.23 Thursday, June 25, 2020

2.23.1 Top new questions this week

Version 12.1.1 unable to type ">"

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224461

Bug introduced in 12.1.1

Since I upgraded to version 12.1.1 I am unable to use > (Shift+.). When I type Shift+. the cell that I am typing in converts to Python. What am I doing wrong?

Steps to ...

asked by wdacda https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27856 15 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 10 votes

Is there any better way to create a, a, a, b, b, b, b, b, c, c from a, 3, b, 5, c, 2?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224581

My attempt:

data = {{a, 3}, {b, 5}, {c, 2}}; 
 
output = Table[#[[1]], #[[2]]] & /@ data // Flatten 
 
{a, a, a, b, b, b, b, b, c, c}

asked by Too Fat Man No Neck https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42141 11 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 18 votes

Selecting lists where all are prime

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224500

Given

    t={{7, 13, 19}, {13, 25, 37}, {19, 37, 55}, {25, 49, 73}, {31, 61, 91}, {37, 73, 109}} 
 
I want to select those lists where all three numbers are primes, so I should get 
{{7, 13, 19}, {37,  ...

asked by user57467 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57467 9 votes

answered by Pillsy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=531 12 votes

Inverting replace direction

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224314

I just have a simple problem. I have a list such that,

rep = { a1 -> b1, a2 -> b2, a3 -> b3}; 
 
I want to invert replace direction such that, 
{ b1 -> a1, b2 -> a2, b3 -> a3}

asked by Saesun Kim https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=29998 8 votes

answered by PaulCommentary https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=54458 8 votes

Calculate Radius of Curvature

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224269

I have a list of coordinates that make a near-parabolic graph, which I managed to fit and calculate the curvature. However, the curvature only outputs a equation. Is there any way to calculate the ...

asked by Char https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66040 8 votes

answered by yarchik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9469 11 votes

Legendre expansion of the Dirac delta function

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224276

There is a known expansion for the Dirac delta function in the interval \( (-1, 1) \) in terms of the Legendre polynomials as

$$\delta(x) = \sum_{k = 0}^{\infty} (-1)^k \frac{(4k + 1) (2k)!}{2^{2k + 1}

asked by Novice https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72595 7 votes

answered by yarchik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9469 11 votes

Which methods are available for NDEigensystem?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224511

I am trying to find out what methods/options are available for NDEigensystem and descriptions of their use. Perusing the help, online Q&As, Mathematica’s in-line autofill, etc., I’ve found a few, ...

asked by Eli Lansey https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9 6 votes

answered by user21 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18437 5 votes

2.23.2 Greatest hits from previous weeks

How can I save both the plot and the legend together?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=35653

In this example, how can I put the legend inside the graph? Currently, when I save the graph, only the graph is saved, not the legend.

Expr1 = -2 p + 1 
Expr2 = 2 p - 1 
Expr3 = p - 1/2 
Plot[{Expr1,  ...

asked by Mika Ike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6543 41 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 35 votes

Formatting legend text font

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3433

I am using this code to plot a graph, and I am trying to make the font of the legend bigger.

<<PlotLegends` 
ListLogLogPlot[{Sort[moby]}, PlotRange -> Full, Joined -> True,

asked by Julia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=525 20 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 25 votes

QR Code in shopping cart handle

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=26268

This week, the market people from my work wanted to put QR codes in shopping cart handles, but when they tested it, the QR code did not work. I noted that the cylindrical curvature (even small) ...

asked by Murta https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2266 194 votes

answered by halirutan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=187 190 votes

Solving \(L=\frac {3}{2} \sqrt {4 \pi ^2 A^2+W^2}-\frac {\sqrt {5 W \sqrt {4 \pi ^2 A^2+W^2}+6 \pi ^2 A^2+3 W^2}}{\sqrt {2}}+\frac {3 W}{2}\) for \(W\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=57763

When I solve the aforementioned equation for \(W\) or \(A\) on Mathematica I get a long and ugly equation in return, namely one of the solutions for \(W\) is: (attempt to read at your own health)

asked by J.D’Almbert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19257 8 votes

answered by Alexei Boulbitch https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=788 14 votes

1 Plot, 2 Scale/Axis

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=627

I would like to plot those two datasets on top of each other. But they have very different range on the \(y\) axis. How can I have two different axis?

I found the following on the help menu but quite ...

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 145 votes

answered by ArgentoSapiens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=92 149 votes

What are the most common pitfalls awaiting new users?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18393

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...

asked by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 462 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 279 votes

How to express trigonometric equation in terms of of given trigonometric function?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=434

How can I express a trigonometric equation / identity in terms of a given trigonometric function?

using following trigonometric identities

Sin[x]^2+Cos[x]^2==1 
Sin[x]/Cos[x]==Tan[x]

asked by Prashant Bhate https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=99 30 votes

answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 37 votes

2.23.3 Can you answer these questions?

Using RegionPlot with NDSolve

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224477

So I have a DE which has no analytical solution and thus solved using NDSolve, involving some parameters like this:

solution=NDSolve[{b/z[t]^4+a z'[t]+z''[t]==0,z[0]==3,z'[0]==3},z,{t,0,5}]

I was ...

asked by t-smart https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53560 1 vote

Implementing binomial expansion of (non-commuting) matrices in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224402

Given two matrices \(A\) and \(B\), their Binomial expansion is, in general, given by (see this page) \((A+B)^n = \sum \limits _{k=0, k=n[2]}^n \Bigg ( \sum \limits _{r=0}^k \binom {k}{r} A^r B^{k-r} \Bigg )\) ...

asked by Rob https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66809 1 vote

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 0 votes

Acquiring images from Zwo ASI camera in Mathematica Home Edition v 11.2.0.0

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224258

I plan to use a ZWO ASI planetary camera (USB connection) for astronomical photography and would like to control the image acquisition using Mathematica. The issue is that although I have installed ...

asked by Dave Baker https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73406 1 vote

2.24 Thursday, June 18, 2020

2.24.1 Top new questions this week

Find second largest elements in list

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223907

Given a list:

lis = {37.21, 37.21, 37.2, 44, 44, 44, 101, 101} 
 
What is a simple way to extract the second largest elements? 
 
In[]:= someFunction[lis] 
 
Out[]= {44, 44, 44}

asked by Conor Cosnett https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36681 14 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 16 votes

The performance of AceFEM in Intel Processor VS. AMD Processor

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224062

I am going to buy a new powerful desktop that I will use to run finite element simulations using AceFEM. I found out that the new AMD Ryzen 9 3950X obtained more points in the CPU Passmark benchmark ...

asked by KratosMath https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53039 8 votes

answered by marko https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=48938 8 votes

Rendering PNG images to spline curves

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223978

I found something interesting on this page (Generic contour smoothing with shading) that could help me improve my images. Unfortunately, they can only be used with graphics generated by the software ...

asked by LCarvalho https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=37895 8 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 9 votes

Parallel computing: cores vs threads

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223899

I’m running Mathematica on a machine wtih 48 cores and 96 threads. I want to limit the number of threads the computation can have access to. If I give LaunchKernels[1] it correctly launches a single ...

asked by Paolo Pani https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73287 8 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 9 votes

Convert ConvexHull to Inequality

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223943

I have the following convex hull.

P0={0,0,0}; 
P1={1,0,0}; 
P2={0,1,0}; 
P3={0,0,1}; 
 
ConvexHullMesh[{P0,P1,P2,P3}]

Now I want the region algebraically as equality of the convex hull generated, in ...

asked by Sumit Banik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=71940 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

Multi-variable Fixed Point Iteration Command?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223817

We want to find the zeros of a multi-dimensional function

  f[x_, y_] = {x + 1/4 (-Cos[x] + Sin[y]), x - y - Sin[y]/4}

To find the zeros, we can initialize and show the iterates using FindRoot

asked by Moo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36141 7 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 7 votes

Unimport wolfram language package

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224140

In Wolfram Language, Import["file.wl"] can import external wolfram package, Is it reversible? Can I unimport some packages? In other means Unset all the Function, Variable which is Set when ...

asked by Audra Jacot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=67051 6 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 7 votes

2.24.2 Greatest hits from previous weeks

Positioning axes labels

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=87388

I need to change the position of my axes labels such that the y-axis label is in the middle and parallel to the y-axis. I’d also like the x-axis label to be in the middle of the x-axis rather than ...

asked by John_dydx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7849 15 votes

answered by Virgil https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27697 16 votes

Using Export[] sends the file where?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8586

I am trying to use the Export command to convert a list of plots into a *.gif file, and the command runs and executes well, but I can’t find the file! Where is it supposed to go? Did it even work?

asked by Patrick Da Silva https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1785 37 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 51 votes

How to tell Mathematica that certain variables are real/imaginary, integer-valued, etc

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66273

I’m trying to expedite some quantum mechanical calculations (expectation values etc.) by running them through Mathematica. When I say, for example,

u[x_] := Sqrt[2/L] * Sin[Pi * n * x / L]

and then ...

asked by Matthew Brunetti https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22304 36 votes

answered by SquareOne https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19960 22 votes

Generate a Unit Circle Trigonometry

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2456

Struggling often with Trigonometry I would like to have some code to generate this Unit Circle Trigonometry. Would be of great help when I need to transform some data :

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 18 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 32 votes

How to add a vertical line to a plot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3561

In the plot below I would like to add two vertical lines at \(x = \frac {\pi }{15} \pm \frac {1}{20}\). How can I do that?

f[x_] := (x^2 z)/((x^2 - y^2)^2 + 4 q^2 x^2) /. {y -> /15, z -> 1, q ->  ...

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 54 votes

answered by Ajasja https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=745 75 votes

Selecting every n-th element from a list

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=64003

I have a list:

data = {4, 5, 7, 8, 9, 5, 3, 2, 1, 2, 13, 12}; 
 
I want to take those elements in the list which are located at equal distances, 
say, every third element, getting the list {7, 5, 1,  ...

asked by Suro https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=20003 34 votes

How to plot an ellipse?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=20100

I’m new to Mathematica, and I’m finding it difficult to plot an ellipse. I tried using

Plot[(x/5)^2 + (y/3)^2 == 1, {x, -5, 5}, {y, -3, 3}]

but I’m getting some errors. Is there something wrong ...

asked by Sriram https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6075 17 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 29 votes

2.24.3 Can you answer these questions?

Export Large Sparse Matrix As .mtx File

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223991

I’m trying to export a large sparse matrix of dimension 1164960 by 1164960 with 17815680 elements as an .mtx file so I can import it into Python. I first the run the following code successfully.

asked by Daniel Berkowitz https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27536 1 vote

What are "VariableReplacementDump" and "TranscendentalDump"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223879

I have run into a Mathematica object I’ve never seen before and Googling those reveals nothing. I’m talking about VariableReplacementDump and TranscendentalDump. Here’s how I got these:

asked by Lokdal https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=23117 1 vote

Why doesn’t Mathematica provide an answer while Wolfram|Alpha does, concerning a series convergence?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=224072

Among other series I’ve been working on, I was asked to find whether \[\sum _n 1-\cos (\frac {\pi }{n})\] converged, and Mathematica’s output to

SumConvergence[1 - Cos[Pi/n], n] simply was repeating the  ...

asked by Hal https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73083 1 vote

2.25 Thursday, June 4, 2020

2.25.1 Top new questions this week

Find if there are consecutive 1s in a binary representation of a number

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223087

Given a list of numbers in decimal form, what is the most efficient way to determine if there are any consecutive 1s in the binary forms of those numbers? My solution so far:

dim = 3; 
declist =  ...

asked by KHAAAAAAAAN https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=65587 10 votes

answered by MassDefect https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42264 10 votes

Why do some PlotThemes not work with Mesh as expected? What can be done about it?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223159

While updating my answer for (189038) I noted that some PlotThemes do not work with Mesh in a meaningful way:

SeedRandom["08.01.2019"]; 
$plotThemes = Map[ToString] @ { Web, Monochrome, Detailed,  ...

asked by gwr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=764 9 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 10 votes

How can I replace a set of Nested For Loops with a Functional Code Alternative?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223023

Despite having looked over various posts concerning optimizing nested For loop expressions into a functional programming equivalent I still can not figure out how to actually to do this. Such ...

asked by Stuart Poss https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=35282 8 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

How to construct this matrix in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222895

I create a symbolic matrix using the following:

mat = ToExpression[Table[StringJoin[{"s", ToString[i], ToString[j]}], {i, 1, d}, {j, 1, d}]]

for arbitrary \(d\). Notice that for \(d=2\), this gives

asked by Sid https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26461 8 votes

answered by Edmund https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19542 6 votes

Rewriting partitions using exponents

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222950

I’m looking for a way to re-express a partition given in full form, like \(\{{2, 2, 1, 1}\}\), into the shortened form \(\{2^2, 1^2\}\), i.e. given a partition with repeated entries, count the number of ...

asked by ZeroTheHero https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=52937 7 votes

answered by kirma https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3056 7 votes

What is the difference between a variable and a "slot variable"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222964

Investigating Function[] , I found:

What is the difference between using a variable (in the case, \(u\)) and a "slot variable"? It seems anything can be done with both. Is there something that ...

asked by Billy Rubina https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=603 7 votes

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 9 votes

Efficiently populate sparse matrix with band structure

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222924

I’m trying to efficiently populate elements of a very large (2^20 x 2^20) symmetric matrix with 1s - luckily the matrix is very sparse, <0.1the matrix has a very well defined ...

asked by KHAAAAAAAAN https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=65587 7 votes

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 8 votes

2.25.2 Greatest hits from previous weeks

Is there something like DensityPlot3D to visualize atomic orbitals?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=32378

I’m visualizing some hydrogen like atomic orbitals. For looking at plane slices of the probability density, the DensityPlot function works well, and with something like:

Manipulate[ 
 DensityPlot[  ...

asked by Peeter Joot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10 44 votes

answered by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 24 votes

How to find integer solutions?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=42359

Following is the equation:

Need to solve for integer values of x,y when a,b lies between -1000 and 1000. Problem is to find the number of integer values of pair (x,y) that satisfy it.

asked by Sahil Sareen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12396 2 votes

answered by bill s https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1783 4 votes

How can I plot the direction field for a differential equation?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8841

I’d like to plot the graph of the direction field for a differential equation, to get a feel for it. I’m a novice, right now, when it comes to plotting in Mathematica, so I’m hoping that someone can ...

asked by Matt Groff https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1735 29 votes

answered by Peter Breitfeld https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=307 24 votes

Calculate the 2D Fourier transform of an Image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=29203

I am new to Mathematica, and using version 8.0.

I would like to calculate the 2D Fourier Transform of an Image with Mathematica and plot the magnitude and phase spectrum, as well as reconstruct the ...

asked by user8727 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8727 14 votes

answered by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 32 votes

How do I draw a pair of buttocks?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66538

I’m trying to develop a function which 3D plot would have a buttocks like shape.

Several days of searching the web and a dozen my of own attempts to solve the issue have brought nothing but two ...

asked by Simpleton Jack https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22399 287 votes

answered by mikuszefski https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7608 440 votes

Elegant operations on matrix rows and columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3069

Question

The Mathematica tutorial has a section ’Basic Matrix Operations’, describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 177 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 60 votes

Finding Limits in several variables

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=21544

Is there a way to find a limit of a multivariable function, like

\[\lim _{(x,y)\to (0,0)} f(x,y)\] with Mathematica?

When \(f\) is continuous, we can use

\[\lim _{(x,y)\to (0,0)}\] ...

asked by Dominic Michaelis https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5899 30 votes

answered by whuber https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=91 41 votes

2.25.3 Can you answer these questions?

How to plot a characteristic curve for silicon diode

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223212

There is a figure given that shows the relation between Forward current(y axis) and forward Voltage (x axis ) for a forward biased diode, with the given formula

asked by Haneen Hussam https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73068 1 vote

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 0 votes

GetProcessMemoryInfo

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223025

The GetProcessMemoryInfo from psapi.dll is a helpful function that can be used to monitor the memory wolframkernel.exe used, where how much memory can be used and is actually used by wolframkernel is ...

asked by Frank https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8207 1 vote

answered by Frank https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8207 0 votes

Solving PDE IVP with inequalities in domains

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=223155

I want to solve the following problem in Mathematica:

I used the following Mathematica code. I am unsure whether this is the correct way of entering the assumptions for the initial and boundary ...

asked by Leponzo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=60411 1 vote

2.26 Thursday, May 28, 2020

2.26.1 Top new questions this week

PlusMinus definition unexpectedly affects plotting

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222380

In version 10.1 I found a strange Plot behavior I did not anticipate. It seems that various heads including PlusMinus are treated as wrappers and stripped by Plot in a way that is not safe. This ...

asked by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 12 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 12 votes

Can someone boost even more my code?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222464

UPDATE

As suggested by Roman, I’ve included here all my code.

I’m using just bult-in function and compile to boost my code, but I think that it can be better. My code looks like

 
    nof = 30; 
     ...

asked by Magela https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68365 11 votes

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 19 votes

Why does NMaximize miss this global maximum?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222716

I am having trouble maximizing a function which appears as a curvature of a planar curve.

{tmin, tmax} = {0, 2 Pi} 
 
f = -((6-3 Cos[t] - Cos[3 t])/((-11+6 Cos[t] + 8 Cos[2 t] - 6 Cos[3 t] + Cos[4 t]) 
  ...

asked by A. Kato https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=62063 8 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 12 votes

How to break the x axis of a plot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222517

I have the following data from which I get an interpolation:

SPE = Interpolation[{{0, 4.08}, {0.5, 9}, {1.5, 12}, {5, 0.158}, {10, 
     0.158}, {15, 0.415}, {20, 0.802}, {30, 2.64}, {40, 4.99}, {60,  ...

asked by mattiav27 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8822 8 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

How to pick consecutive numbers from list?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222407

Question is very simple. If we have

tst = {2,3,4,6,7,9,11} 
 
result must be 
 
{{2,3,4}, {6,7}, {9}, {11}} 
 
 
There are similar questions, but not exact. 
 
My best solution is: 
 
myFun[arr_] :=  ...

asked by lesobrod https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5950 8 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 14 votes

Multiply each element of second position of two list

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222548

If I have two list such as:

list1 = {{40., 7.50551*10^-10}, {40.,7.50557*10^-10}, {40.,7.50566*10^-10}, 
         {40.0001, 7.50578*10^-10}, {40.0001, 7.50591*10^-10},{40.0001, 7.50607*10^-10}, 
        ...

asked by John https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72900 7 votes

answered by David Keith https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44700 7 votes

Area/Volume of a 2D/3D object as it is filled up with water

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222837

How could I get the volume of water on a region as it is filled up with water from below? Assume gravity points in some appropriate downward axis like y (or z in 3D) so the water fills upward from ...

asked by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 6 votes

2.26.2 Greatest hits from previous weeks

Plotting the frequency spectrum of a data series using Fourier

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18082

testData = Table[N@Sin[500 x], {x, 0, 100}]; 
ListLinePlot[Abs[Fourier[testData]], PlotRange -> Full] 
 
Gives me 
 
Which I do not expect because the Fourier Transform is FourierTransform[Sin[500  ...

asked by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 14 votes

answered by KennyColnago https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3246 16 votes

Generate a Unit Circle Trigonometry

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2456

Struggling often with Trigonometry I would like to have some code to generate this Unit Circle Trigonometry. Would be of great help when I need to transform some data :

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 18 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 32 votes

Figuring when the minute and hour hand coincide on a clock

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=573

I would like to list all possible times in a 12-hour period, where the hour hand overlaps the minute hand completely. This is really a question about three distinct things - to be done in Mathematica ...

asked by Steve D https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=191 15 votes

answered by Verbeia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8 21 votes

Formatting legend text font

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3433

I am using this code to plot a graph, and I am trying to make the font of the legend bigger.

<<PlotLegends` 
ListLogLogPlot[{Sort[moby]}, PlotRange -> Full, Joined -> True, 
     ...

asked by Julia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=525 20 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 25 votes

How do I clear all user defined symbols?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=850

Is there some way to do this other than going to 
Evaluation -> Quit kernel and firing a new one up?

asked by niklasfi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=82 95 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 92 votes

How to calculate contour integrals with Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=34073

How to calculate the integral of \(\frac {1}{\sqrt {4 z^2 + 4 z + 3}}\) over the unit circle counterclockwise for each branch of the integrand?

asked by user64494 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7152 40 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 63 votes

Calling Correct Function for Plotting DiracDelta

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3506

I am wondering what is the correct function in Mathematica to plot the true impulse function, better known as the DiracDelta\[\] function. When using this inside of a function or just the function ...

asked by night owl https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=116 17 votes

answered by Heike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46 19 votes

2.26.3 Can you answer these questions?

Natural deduction with FindEquationalProof

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222577

Out of curiosity, I’m trying to implement a natural deduction prover in Mathematica using FindEquationalProof. So far, I’ve implemented a few of the easier rules:

axioms = { 
  ForAll[{A, B},  ...

asked by imas145 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61387 1 vote

NDSolve very slow

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222571

I am trying to run this code to get the output from NDSolve for 4 dynamical equations. However, I have two issues:

(1) It is taking a very long time (can reach several hours for a given instance) ...

asked by user135626 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19550 2 votes

Change Font and Size of Print[] output

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222504

I managed to create a definition for the "Print" style, following the instructions here. However, the result does not work in my v.12.1. On the plus side, a "Print" entry exists at the bottom of the ...

asked by Nicholas G https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=43662 1 vote

2.27 Thursday, May 21, 2020

2.27.1 Top new questions this week

How to clear all definitions matching f[1, ...] but not f[2, ...]?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222002

I would like to clear all definitions of the form f[1,...] in such a way that f[2,...] remain unaffected.

The two methods I know to clear variables don’t seem to apply to this situation:

Pattern

asked by WillG https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=59634 10 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 15 votes

Rescaling data to make a "continuous" function

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222252

I have acquired many sets of data, which all represent a single function, but which are randomly rescaled by a constant (due to the measurement specifics). I’m looking to effectively stitch them ...

asked by ChaSta https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=48457 9 votes

answered by aooiiii https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68990 7 votes

Why does Mathematica ignore 1 as an exponent? Or as a coefficient?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221934

Two different examples of same problem:

 
In: Cases[{f^2, g^3, k^p, h}, x_^n_ -> n] 
 
Out: {2,3,p}     # The result misses the exponen of h, '1'

The same problem in a different context:

asked by MaxB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66077 8 votes

answered by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 11 votes

How to add ’border’ to Voronoi diagram

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221984

Suppose I have a set of points pts, from which I generate a Voronoi diagram VD:

pts = RandomReal[{-1, 1}, {100, 2}]; 
VD = Show[VoronoiMesh[pts], Graphics[{Red, Point[pts]}]] 
 
Now, as per the  ...

asked by TumbiSapichu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53229 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

Contracting indices in lists

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222037

Using an answer to this question (Working with Dirac Gamma Matrices using FeynCalc - A simple problem), I defined

Clear[] 
SetAttributes[, Listable] 
[_] := If[ == 0, KroneckerProduct @@  ...

asked by FB20 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72314 6 votes

answered by Chanto https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=35091 4 votes

How to extract all possible sub-products which match specific pattern?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222285

I have an expression of the form

expr = 3*(a.b)*(c.d)*f[x] + 5*(m.n)*(p.q)*(r.s)*f[y] 
 
and want to extract all possible subexpressions matching the pattern ((_).(_))*f[_]. 
Expected result (in  ...

asked by Shadowray https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=47416 6 votes

answered by Marius Ladegård Meyer https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22099 7 votes

Raytracing using Regions & NSolve

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222105

I want to use geometric shapes in Mathematica to build complex shapes and use my raytracing algorithm on it. I have a working example where we can get the intersections from a combination of a Cone[] ...

asked by Tomi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36939 6 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 5 votes

2.27.2 Greatest hits from previous weeks

Help find a bright object on Mars!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11819

In today’s news, scientists found a bright object on one of Curiosity’s photos (it’s near the bottom of the picture below). It’s a bit tricky to find - I actually spent quite some time staring at the ...

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 197 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 255 votes

Figuring when the minute and hour hand coincide on a clock

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=573

I would like to list all possible times in a 12-hour period, where the hour hand overlaps the minute hand completely. This is really a question about three distinct things - to be done in Mathematica ...

asked by Steve D https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=191 15 votes

answered by Verbeia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8 21 votes

How to perform a multi-peak fitting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=26336

I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3).

asked by Everett You https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1389 54 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 54 votes

Using Export[] sends the file where?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8586

I am trying to use the Export command to convert a list of plots into a *.gif file, and the command runs and executes well, but I can’t find the file! Where is it supposed to go? Did it even work?

asked by Patrick Da Silva https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1785 37 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 49 votes

Can Mathematica do symbolic linear algebra?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3242

For instance, is there some way I can say "let A and B be arbitrary real \(m\times n\) and \(k\times m\) matrices, Simplify[Transpose[Transpose[A].Transpose[B]]]" and Mathematica would simplify it to B.A?

asked by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 61 votes

Assign the results from a Solve to variable(s)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=6669

I understand Mathematica can’t assign the results of a Solve to the unknowns because there may be more than 1 solution. How can I assign the 4 values of following result to variables?

asked by stevenvh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1450 52 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 33 votes

Creating a table/Matrix during a For loop

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2930

I have a For loop (with i as a counter), which calculates different values (y1, y2, y3,...) as a function of the variable x. How can I create a table/matrix which contains i lines, each line ...

asked by Solarboy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=727 10 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 14 votes

2.27.3 Can you answer these questions?

Computations with OptimizedExpressions without completely expanding them

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221938

I have to manipulate huge expressions that are rational functions of many (30) variables with integer coefficients. Storing them just as a ratio of two polynomials would be impractical. But they can ...

asked by Vladimir Reshetnikov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7288 2 votes

LeviCivitaTensor contraction indices

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=222179

apparently my computer has problems when I try to perform a calculation with TensorContract.

In particular, with the second answer to my previous question Contracting indices in lists, I want to ...

asked by FB20 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72314 1 vote

Using Fold[ or Map[ Better?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221941

I’m working through MMA Cookbook by Mangano, page 54. He shows Map is a compact form of Fold function. Is using Fold function important?

myMap3[f_, l_] := Fold[Prepend[#1, f[#2]]&, {}, l]

asked by code9910743 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=59860 2 votes

2.28 Thursday, May 14, 2020

2.28.1 Top new questions this week

What causes Module variables to leak?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221436

Sometimes, after writing code like

f[] := Module[{a}, ...] 
 
and running f[] multiple times, there will be many Temporary symbols of the form a$123 in 
the Global namespace. Sometimes this happens  ...

asked by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 25 votes

answered by Leonid Shifrin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=81 22 votes

Looping through all functions defined in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221555

Is there a way to loop through all the Functions (Elementary and Special functions) that exist in Mathematica?

I want to construct a table of some identities and maybe I can discover something ...

asked by Micha Kuczynski https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72609 12 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 13 votes

Solver for COVID-19 epidemic model with the Caputo fractional derivatives

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221609

As it is known in biological system with memory it would be suitable to use fractional derivatives to describe evolution of the system. In a current version of Mathematica 12.1 there is no special ...

asked by Alex Trounev https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58388 10 votes

Possible bug in finite sum over inverse squares \(\sum \limits _{i=1}^n \frac {1}{(x (n-i)+i)^2}\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221373

Revisiting the problem Limit of partial sums involving inverse squares I found another difficulty with Sum[]

Consider this sum

s[x_, n_] :=  Sum[ 1/(i + (n - i) x)^2, {i, 1, n}] 
 
Here we assume x  ...

asked by Dr. Wolfgang Hintze https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=16361 10 votes

answered by Soner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=49198 13 votes

Removing banal words from a list

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221540

NB: I am aware of the DeleteStopwords symbol.

I want to remove from a list of words the ones that are likely to be more banal. So for instance if we have

{"exegesis", "mystification", "bread",  ...

asked by Diffycue https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46327 9 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 10 votes

How to reproduce Wolfram Language’s base64 encoded string with command-line tool?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221381

With Wolfram Language:

In[7]:= ExportString["foobar", "Base64"] 
 
Out[7]= "Zm9vYmFyXDo0ZTJkXDo2NTg3" 
 
 
With the closest command-line software I could think of 
 
echo -n 'foobar' | openssl base64     ...

asked by qazwsx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=357 9 votes

answered by Jason B. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9490 17 votes

Does the following change to MKL environment variable boost Mathematica speed on AMD CPUs

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221767

I personally do not have an AMD CPU but since they are literally becoming quite hot these days, I thought whether the following fix (as proposed here: ...

asked by Ali Hashmi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27331 7 votes

answered by ilian https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=145 9 votes

2.28.2 Greatest hits from previous weeks

Multivariable Taylor expansion does not work as expected

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=15023

The basic multivariable Taylor expansion formula around a point is as follows:

$$ 
f(\mathbf r + \mathbf a) = f(\mathbf r) + (\mathbf a \cdot \nabla )f(\mathbf r) + \frac{1}{2!}(\mathbf a \cdot  ...

asked by matheorem https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4742 55 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 61 votes

How to calculate scalar curvature Ricci tensor and Christoffel symbols in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8895

I am seeking a convenient and effective way to calculate such geometric quantities. I’ve used packages like TensoriaCalc, but they don’t work at all time. Sometimes, I run into the following error:

asked by Zoe Rowa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1713 36 votes

answered by Yi-Zen Chu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4869 17 votes

How to create effect like Van Gogh’s stroke brush?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39003

I need to apply Van Gogh’s stroke brush effect to a random image

Take the following image as an example:

Thank you so much if you could help!

asked by user10495 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10495 33 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 51 votes

How to perform a multi-peak fitting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=26336

I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3).

The ...

asked by Everett You https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1389 54 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 54 votes

What are the most common pitfalls awaiting new users?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18393

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...

asked by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 460 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 277 votes

How to find integer solutions?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=42359

Following is the equation:

Need to solve for integer values of x,y when a,b lies between -1000 and 1000. Problem is to find the number of integer values of pair (x,y) that satisfy it.

asked by Sahil Sareen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12396 2 votes

answered by bill s https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1783 4 votes

LaTeXand Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=736

I quite often would like to draw graphics in my LaTeXdocuments using Mathematica. I have encountered three problems. I would like to know if there are any workarounds to these problems

I would ...

asked by Thomas Rot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=227 124 votes

answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 45 votes

2.28.3 Can you answer these questions?

Construct a binary tree where nodes are labeled according to given rule

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221405

I want to plot a binary tree in Mathematica where the nodes are labeled according to a given rule. In fact, whether a node has a left child or a right child or both, will be determined by a rule. And ...

asked by Mwen Rele https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72568 1 vote

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 0 votes

How to get proper TeX output from splicing the following file?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221414

In order to let other users with Mathematica 12.x test this problem for me, I now use FileTemplate instead of Splice.

I want to splice (with FileTemplate) the following file that has been simplified ...

asked by Money Oriented Programmer https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42141 1 vote

Application of spatially varying boundary conditions and source term in AceFEM

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221489

I am trying to model a simple 2D steady state heat conduction problem using automatically generated Q2 elements.

The problem consists of a square domain with prescribed temperatures along the bottom ...

asked by DvanHuyssteen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69831 1 vote

2.29 Thursday, May 7, 2020

2.29.1 Top new questions this week

‘Count‘ for ‘SparseArray‘

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221160

Why does Count not work with SparseArrays, and is there any function I can use to replace it?

What would be an efficient workaround?

Example:

a=ConstantArray[0,{10},SparseArray]; 
Count[a,0] (*  ...

asked by Daniel https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19534 9 votes

answered by thorimur https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=63584 8 votes

What is the best and most efficient way to curry?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220972

Suppose I have a function with a signature like g[expr, _?(f), {1}, Heads -> False] 
and I want to access it as an operator by giving the first argument last. 
I see there are various ways of doing  ...

asked by user13892 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13892 9 votes

Mathematica and Excel

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221155

I have a number of large data sets in Excel and .dat from OMEdit Modelica that then need to import some or all of it to Mathematica for manipulation and plotting. Importing the data is easy enough ...

asked by Chris B https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58764 8 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 10 votes

Local variables in sums and tables - best practices?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221079

Stumbled on Local variables when defining function in Mathematica in math.SE and decided to ask it here. Apologies if it is a duplicate - the only really relevant question with a detailed answer I ...

asked by https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=35000 8 votes

answered by WReach https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=142 5 votes

How can I make Mathematica solve this set of four equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221082

I use Mathematica version 12.1 on Windows 10.

I have four equations in four unknowns.

Is there a trick to make Mathematica solve these?

I tried Solve and NSolve and it is not able to do it. ...

asked by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 8 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5 7 votes

obtain properly formatted code from autogenerated package

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220842

Overview: I have written a few mathematica packages, always using the method of writing my code in a mathematica notebook and letting mathematica autogenerate the .m package file. Currently I do not ...

asked by Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5033 8 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 6 votes

Why is StreamPlot plotting direction like this?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221255

I am doing a StreamPlot and something seems wrong with the output.

  StreamPlot[{0, -(y - x)^3}, {x, -3, 3}, {y, -3, 3}] 
 
The plot is attached and I highlighted the issue in red 
 
Shouldn't the  ...

asked by Moo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36141 7 votes

answered by user2432923 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61643 5 votes

2.29.2 Greatest hits from previous weeks

My Girlfriend is going to prison...Save her with Math

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=135937

Salacious title, but true story.

 dmethyl1 = { 
      {0, 0}, 
      {.25, 1}, 
      {.5, 7}, 
      {1, 26}, 
      {1.5, 40}, 
      {2, 45}, 
      {2.5, 45}, 
      {3, 44}, 
      {3.5, 44}, 
      {4,  ...

asked by Prisoners Dilema https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46025 42 votes

answered by bobthechemist https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7167 23 votes

Calculate the 2D Fourier transform of an Image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=29203

I am new to Mathematica, and using version 8.0.

I would like to calculate the 2D Fourier Transform of an Image with Mathematica and plot the magnitude and phase spectrum, as well as reconstruct the ...

asked by user8727 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8727 14 votes

answered by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 32 votes

Help find a bright object on Mars!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11819

In today’s news, scientists found a bright object on one of Curiosity’s photos (it’s near the bottom of the picture below). It’s a bit tricky to find - I actually spent quite some time staring at the ...

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 197 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 255 votes

Are you interested in purchasing David Wagner’s "Power programming with Mathematica"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=16485

I recently contacted McGraw-Hill to see if they have a mechanism in place for printing out-of-print books that are still of interest. Specifically, I asked about "Power programming with Mathematica" ...

asked by Todd Allen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=249 158 votes

answered by Todd Allen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=249 232 votes

Even Fibonacci numbers

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=37266

Today, I found the Euler Project. Problem #2 is

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, ...

asked by xyz https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9627 34 votes

answered by rcollyer https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=52 46 votes

What does # mean in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19035

I asked Mathematica to compute the following

Solve[c (1-x)^2-x^(1/4) == 0, x] 
 
 
and it returned this: 
 
  x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 c^4 + 70 #1^4 c^4 - 56 #1^3 c^4 + 28  ...

asked by ronanymous https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5730 37 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 63 votes

How to ask Mathematica to imitate Andy Warhol’s pop-art painting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=59132

I tried to ask Mathematica to imitate Andy Warhol, let it convert a Marilyn Monroe’s portrait so that it looks like Warhol’s world famous pop-art painting. However, the result shown below is far from ...

asked by Putterboy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=16069 50 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 65 votes

2.29.3 Can you answer these questions?

How to specify AxesOrigin for DateListPlot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221222

I would like to generate a plot with the y axis on the graph. In a "normal" numeric plot I do this using the AxesOrigin option. How to I specify the crossing point in a DateListPlot?

Here’s the MWE ...

asked by jmm https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57731 1 vote

How to create a seek bar with Slider

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221284

I am trying to create a simple audio player but I am stuck at designing the seek bar. I am using the AudioStream framework.

After loading music in a variable stream, I can access its position using ...

asked by Sâu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=67944 1 vote

How can I get a plot of "surface area coverage" of a parametric plot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220846

I have a parametric function defined by the x and y functions:

 
x = r*Cos[w_0*t - w_L*t] + 
  z*Cos[w_P*t - w_L*t] 
 
y = r*Sin[w_0*t - w_L*t] + 
  z*Sin[w_P*t - w_L*t]

I can change the variables ...

asked by Cameron_3298 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72418 1 vote

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 0 votes

2.30 Thursday, April 23, 2020

2.30.1 Top new questions this week

Wrong function of NotebookDirectory[] in the 12.1 version

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219700

Bug introduced in 12.1.0

Could anybody help?

NotebookDirectory[] function began working wrong in 12.1 (the bug was not present in 12.0 and earlier versions).

When folder name includes Russian ...

asked by Alexander https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72011 13 votes

answered by ilian https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=145 10 votes

How complete is the WL’s string language?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220003

Consider the following example:

Suppose I am interested in words that contain all the letter of the list 
characters={"e","t","l","a","b"} at least once. An example would be 
the word "abilities" or a  ...

asked by user13892 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13892 12 votes

answered by Jason B. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9490 11 votes

Reusing PARDISO symbolic factorization

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219687

Is there a way to do this natively in Mathematica? I read in several places that this is possible with LibraryLink, but I don’t have a lot of experience with C and so I’m having trouble implementing ...

asked by beets https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72007 8 votes

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 13 votes

How to Improve FEM Solution with NDSolve?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219990

First some comments. This same calculation works beautifully in 2D with essentially the same code. I have copied it largely unaltered into 3D as part of a migration to 3D so that I can do more complex ...

asked by Paul Harrison https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=69377 7 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 8 votes

What is the difference between Wolfram Script and Wolfram Engine?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219963

I don’t understand the difference between these products:

Wolfram Script

Wolfram Engine

Would someone help me understand what these are? And how it differs from just using Mathematica in the ...

asked by QuantumDot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2048 6 votes

answered by morbo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=48686 0 votes

Implicit Riccati Equation Solver (to find the anti-stabilizing solution

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219758

I’ve found that the latest MATLAB icare() solver includes the possibility to find also the anti-stabilizing solution of the Riccati equation. I haven’t found a similar option on Mathematica. Is there ...

asked by Mirko Aveta https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36621 6 votes

answered by Suba Thomas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5998 5 votes

Dates not printed in DateListPlot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220154

A simple example

Clear["Global`*"]; 
 
data = TimeSeries[{1, 2, 1, 3, 0, 0, 0, 2, 21, 15, 21, 7, 11, 5, 10, 
       18, 73, 38, 103, 21, 35, 31, 46, 31, 35, 94, 71, 48, 78, 71, 74, 
       95, 95, 56,  ...

asked by Vaggelis_Z https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5052 5 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 1 vote

2.30.2 Greatest hits from previous weeks

Mathematica code for Bifurcation Diagram

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=13277

At the moment I am trying to construct a bifurcation diagram of the iterative function \(f(x)=\) \(ax-1.1975x^3\). I’ve scoured the internet for pre-made bifurcation diagrams and found many (mostly of the ...

asked by Mel https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3249 26 votes

answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 45 votes

Drawing a square root spiral

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66969

Here is a start. I’m looking for a nice way to draw it.

Graphics[{EdgeForm[Black], White, 
  Polygon @ {{0, 0}, {-1, 0}, 
    Sqrt[2] {Cos[#], Sin[#]} &[Pi - (ArcCot[1])]}, 
  Polygon @ {{0,  ...

asked by matrix89 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5379 24 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 21 votes

How do I draw a pair of buttocks?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66538

I’m trying to develop a function which 3D plot would have a buttocks like shape.

Several days of searching the web and a dozen my of own attempts to solve the issue have brought nothing but two ...

asked by Simpleton Jack https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22399 287 votes

answered by mikuszefski https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7608 440 votes

How can I improve Mathematica’s resolution on a macbook retina display?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18419

Mathematica 9.0 looks a bit fuzzy on the retina screen, how can I increase the resolution?

Here another screenshot showing a direct comparison between the browser and Mathematica

asked by Tom Wellington https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2437 43 votes

answered by canadian_historian https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19 20 votes

Using Export[] sends the file where?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8586

I am trying to use the Export command to convert a list of plots into a *.gif file, and the command runs and executes well, but I can’t find the file! Where is it supposed to go? Did it even work?

asked by Patrick Da Silva https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1785 37 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 49 votes

How to create effect like Van Gogh’s stroke brush?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=39003

I need to apply Van Gogh’s stroke brush effect to a random image

Take the following image as an example:

Thank you so much if you could help!

asked by user10495 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10495 33 votes

answered by Simon Woods https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=862 51 votes

Elegant operations on matrix rows and columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3069 Question

The Mathematica tutorial has a section ’Basic Matrix Operations’, describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 177 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 60 votes

2.30.3 Can you answer these questions?

Can one use .wls (script) files in a simple way, like Matlab scripts?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219919

I have been fighting unsucessfully with the intricacies of creating Mathematica packages (Private, scopes , context) for a long time. I just need a simple version of Matlab scripts, to be able to ...

asked by florin https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=54979 1 vote

Introduction to Probability

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219883

Is there any newer book or online resource that would be good introductory text to probability with Mathematica? I have Introduction to Probability with Mathematica by Hastings but it is over 10 years ...

asked by grga https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70392 1 vote

Do palettes limit the execution time of a user-defined function?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219973

I have defined a function ConvertToMarkdown that does some long processing of a notebook: converts it to markdown, save inputs/outputs as images, generates a word cloud etc., that can take multiple ...

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 1 vote

2.31 Thursday, April 16, 2020

2.31.1 Top new questions this week

Raytracing; why so slow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219629

I’m trying to get some rays to bounce in a circle. But I want to be able to control the reflections, i.e. the direction the rays bounce in the circle. I have a MWE below, and it is severely limited by ...

asked by Tomi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36939 10 votes

answered by MassDefect https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42264 18 votes

How use the black mode permanently

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219317

Now I can use this functionResourceFunction["DarkMode"][] to use the dark mode, but when I turn on Mathematica again, the black mode will not work. How can I set to use the black mode permanently.

asked by https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=71882 9 votes

answered by M.R. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=403 5 votes

DeleteCases depending on all elements

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219412

I have a listed of Tupels

list = {{10, 5}, {20, 4}, {20, 3}, {10, 6}}; 
 
If there are two elements a and b for which 
 
a[[1]] <= b[[1]] && a[[2]] <= b[[2]] 
 
then I would like to delete  ...

asked by fravity https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22275 8 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

subsubsectionMathematica is unable to compute the derivative of the function \(\frac {\sin ^2(x)}x\) https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219273

Consider the function \[f: \mathbb R\to \mathbb R, x\mapsto \begin {cases}\frac {\sin ^2(x)}x, & x\neq 0, \\ 0, & x=0.\end {cases}\]

It is clear that \(f\in \mathcal C^1(\mathbb R)\) and that

asked by Maximilian Janisch https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68670 8 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 12 votes

How to download "Epidemic Data for Novel Coronavirus COVID-19"

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219282

I am using Mathematica and I would like to download the dataset "Epidemic Data for Novel Coronavirus COVID-19" for basic investigation from Wolfram homepage. Can anyone give me some instructions or ...

asked by Johann Riedler https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=71867 7 votes

answered by morbo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=48686 6 votes

NIntegrate vs quadGK in Julia

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219198

I am trying to understand the numerical integration routine by using as a benchmark the function

f[x_] := -x^2 + x^4 
 
 
used to define the following function 
 
g[z_] := NIntegrate[1/Sqrt[-f[x]], {x, z,  ... 

asked by Smerdjakov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=55615 7 votes

answered by MassDefect https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42264 7 votes

Overflow with NDSolve

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219593

Backslide introduced in 10.0, persisting through 12.1.

I am trying to solve the following differential equation and plot the result:

ClearAll["Global`*"] 
rin = 10^-30; 
sol = NDSolve[{Sqrt[x]  ...

asked by mattiav27 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8822 6 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 2 votes

2.31.2 Greatest hits from previous weeks

What are the most common pitfalls awaiting new users?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18393

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...

asked by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 459 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 277 votes

How to find the position of elements in a list satisfying criteria

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=180

Say I have a list x={2,4,6,8,10} and I want to find out the positions 
of the elements that are greater than 7. 
 
Select[x, #>7&] gives the elements themselves, and Position[x,8] gives the  ... 

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 62 votes

answered by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 60 votes

How do I draw a pair of buttocks?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66538

I’m trying to develop a function which 3D plot would have a buttocks like shape.

Several days of searching the web and a dozen my of own attempts to solve the issue have brought nothing but two ...

asked by Simpleton Jack https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22399 287 votes

answered by mikuszefski https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7608 440 votes

How can I plot a graph of an integral?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=78451

I want to plot the following function:

\[\int \left (\frac {\Gamma (x+1)}{2}-\frac {\Gamma (x-1)}{2}\right ) \, dx\]

asked by Anixx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=651 3 votes

answered by k_v https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=24727 8 votes

Make a scatter plot from two lists

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=21884

I have two lists of values

xx = {0.1, 0.3, 0.35, 0.57, 0.88, 1.0} 
yy = {1.2, 3.5, 4.5, 7.8, 9.0, 12.2}

I want to make a scatter plot (list plot) with xx as x axis and yy as y axis. The help ...

asked by Patrick Li https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2403 27 votes

answered by Eric Thewalt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6313 38 votes

Are you interested in purchasing David Wagner’s "Power programming with Mathematica"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=16485

I recently contacted McGraw-Hill to see if they have a mechanism in place for printing out-of-print books that are still of interest. Specifically, I asked about "Power programming with Mathematica" ...

asked by Todd Allen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=249 158 votes

answered by Todd Allen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=249 232 votes

Extract real part of a complex expression better than Re does

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3306

I have a complex expression with real positive variables only.

Mathematica Input Style:

PP = -(( ( Cosh[y1 ] +  Sinh[y1 ])(- Cosh[(-L +  y2) ] +  Sinh[(-L + y2) ])) 
    /(s (2   Cosh[L ]  ...

asked by max https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=796 31 votes

answered by nixeagle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=814 50 votes

2.31.3 Can you answer these questions?

With a Large output, clicking Show all or Show more freezes Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219430

Running the following code takes about 30 min on my laptop (everything before the Reduce is instant) and produces a Large output that Mathematica does not display, only shows buttons Show more, Show ...

asked by Sander Heinsalu https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6211 1 vote

MathMF Error, Can’t Import VIdeo

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219195

I am getting this error HElP....

asked by Ajit Yadav https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=71840 1 vote

Best parameter for smoothing splines

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219616

I am trying to implement a module to determine the best value for the smoothing parameter of a smoothing spline interpolation of a given dataset. To calculate the cross-validation score of a given ...

asked by Daniele Binosi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=25023 1 vote

2.32 Thursday, April 9, 2020

2.32.1 Top new questions this week

Adding Regularisation to Built-in Interpolation function

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218764

tl;tr; How to improve performance of regularised Interpolation?

Context

Since Version 12, Mathematica now incorporates a range of (underrated IMHO) regularisation methods to Fit and FindFit.

asked by chris https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1089 17 votes

answered by chris https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1089 7 votes

How to model diffusion through a membrane?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218983

This is a follow-up on How to handle discontinuity in diffusion coefficient?

Consider diffusion of \(u(t,x)\) on the domain \(x \in [0,2]\) with some simple boundary conditions such as \(u(0) = 2, u(2) =\)

asked by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 13 votes

answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 7 votes

How to draw a "proper" tree diagram

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218859

TreePlot[{ 
    {0 -> "Mr 1", 1/10}, 
    {0 -> "Mr 2", 2/10}, 
    {0 -> "Mr 3", 3/10}, 
    {0 -> "Mr 4", 4/10}, 
    {"Mr 1" -> "A1",  2/10 }, 
    {"Mr 1" -> "B1",  1/10 }, 
    {"Mr 1"  ...

asked by CasperYC https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=62701 13 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 18 votes

How can I list all tech note pages?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219033

It seems since v12.1 a new doc type, tech note, is included in the documentation.

However, I cannot find an index page for the tech notes. So how can I list all such tech note pages?

asked by sunt05 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=260 10 votes

answered by WReach https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=142 11 votes

Generating long binary lists fast?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219115

Given list \(L\) consisting only of \(0\)’s and \(1\)’s, we read \(L\) backwards and construct a new list \(O\) such that: (we start with \(O=\{1\}\) and then apply the two rules:)

if we encounter \(n\) ...

asked by Vepir https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=49840 9 votes

answered by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 5 votes

Control grain size of stipple shading

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219020

Mathematica 12.1 introduced a number of amazing shaders such as StippleShading.

Is there a way to control the grain size of StippleShading?

On a standard resolution screen it looks like this:

asked by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 9 votes

Extracting COVID AdministrativeDivision data from Wolfram Resource

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218833

Wolfram makes the COVID-19 case data available in a form that is conveniently formatted for processing in Mathematica.

It can be accessed using:

data2 = ResourceData[ResourceUpdate["Epidemic Data  ...

asked by theorist https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45215 9 votes

answered by LouisB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22158 7 votes

2.32.2 Greatest hits from previous weeks

How to make Jacobian automatically in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=5790

If we have two vectors, \(a\) and \(b\), how can I make Jacobian matrix automatically in Mathematica?

$$ a=\left( 
\begin{array}{c} 
 x_1^3+2x_2^2 \\ 
 3x_1^4+7x_2 
\end{array} 
\right);b=\left(

asked by George Mills https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1012 37 votes

answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 49 votes

LaTeXand Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=736

I quite often would like to draw graphics in my LaTeXdocuments using Mathematica. I have encountered three problems. I would like to know if there are any workarounds to these problems

I would ...

asked by Thomas Rot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=227 124 votes answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 45 votes

Where can I find examples of good Mathematica programming practice?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18

I consider myself a pretty good Mathematica programmer, but I’m always looking out for ways to either improve my way of doing things in Mathematica, or to see if there’s something nifty that I haven’t ...

asked by J. M.’s technical difficulties https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 536 votes

answered by faysou https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66 473 votes

How can I plot the direction field for a differential equation?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8841

I’d like to plot the graph of the direction field for a differential equation, to get a feel for it. I’m a novice, right now, when it comes to plotting in Mathematica, so I’m hoping that someone can ...

asked by Matt Groff https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1735 29 votes

answered by Peter Breitfeld https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=307 24 votes

Mathematica command that allows it to read my intentions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=194384

In version 2.0 of Mathematica there was a command, ReadProgrammerIntentions[ ] which allowed it rapidly compose code that could solve problems simple to complex, based on my requirements. Understand ...

asked by MikeY https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=47314 52 votes

answered by MarcoB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27951 38 votes

Parallel and perpendicular symbol from Mathematica to LaTeX

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=46538

I want to get the following expression from Mathematica to LaTeX:

\[ \begin {bmatrix} E_{\parallel } \\ E_{\perp } \end {bmatrix} \]

I have tried to use inbuilt ’symbol’ character from the special ...

asked by Steve Hatcher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13314 18 votes

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 25 votes

Is there any algorithm that runs faster in Mathematica than in C or Fortran?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=208045

I’m just curious. My friend just told me that Mathematica is mostly for symbolic calculation and not efficient for Numerical computations. He told me that’s the reason most of the people don’t use ...

asked by Gummala Navneeth https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66938 44 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 73 votes

2.32.3 Can you answer these questions?

How can I modify the code to speed up the ‘Do‘?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219057

I need to use the following code to do some calculations. But the running speed of this code is too slow. How can I modify this code to improve the running speed?

   Cb = 0.5; 
    Ch = 5./7; 
     =  ...

asked by Please Correct GrammarMistakes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 1 vote

Need help with Limit (DirectedInfinity)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=219035

I tried to compute the following limit:

Limit[Series[ 
  1/(1/x^2) (Sin[y x]/(x^4))^2 - Sin[y x]/y(x^3) + 1/x^2, {x, 0, 5}], 
 x -> 0, Assumptions -> {y > 0}] 
 
the output :

asked by Johe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=71663 1 vote

How can i use Butterworth filter written in matlab to Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218701

i need help to convert this code written in matlab about Butterworth filter:

 %remove high-frequency components by 0.5-h butterworth filter; 
 n =2; 
 Wn =[1/30/0.5];   %30-min low-pass filter (LPF)%

asked by Iman Khaki https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=71671 1 vote

2.33 Thursday, April 2, 2020

2.33.1 Top new questions this week

How to determine if two mutable data structures are the same?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218535

How can I determine if two mutable data structures (DataStructure) are truly the same? I do not mean checking if they have the same value. I mean checking if they are the same data structure, i.e. ...

asked by Szabolcs ( https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 ) 15 votes

answered by ilian ( https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=145 ) 14 votes

Is there official documentation for official documentation and getting help system of Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217230

Mathematica has very high quality and extensive documentation and good getting help system (? Solve as an example; there maybe are more too). Is there all including official documentation about ...

asked by vasili111 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=11639 14 votes

answered by WReach https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=142 11 votes

Mottled appearance of ContourPlot3D with transparency

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217226

I’m trying to make a ContourPlot3D that needs to be transparent. With transparency, however, something odd happens.

With PerformanceGoal->"Speed", the colors look fine.

With ...

asked by Peter Todd Williams https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70508 11 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

Dividing by Zero - Unexpected Result

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218539

When I divide this number by zero I get this for an answer. 
 
ans = 2345900/0 
 
What is surprising is that in taking the square root, Mathematica seems to map the entire universe to some town  ...

asked by MikeY https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=47314 9 votes

How can I plot a parametric equation with ś?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217227

I want to draw a parametric equation with ś like the figure below: 
 
But I don't get the result I want when I run the following code. What can I do to get it? 
 
ParametricPlot[{x, śx^2}, {x, 0, 1}, 
   ...

asked by Please Correct GrammarMistakes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 9 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 16 votes

Mathematica numerical "error" for simple multiplication?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217205

In[71]:= 0.6*0.8048780487804877` 
 
Out[71]= 0.482927 
 
In[72]:= 0.3*0.8414634146341463` 
 
Out[72]= 0.252439 
 
In[74]:= (0.6*0.8048780487804877`) + 0.3*0.8414634146341463` 
 
Out[74]= 0.735366 

asked by htam_ujn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70502 9 votes

answered by m0nhawk https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2342 8 votes

Why can’t I use Inactive[D] in NDSolve?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217169

I have a 2D rectangular domain with -L/2 < x < L/2 and 0 < y < D0, which is divided into two parts, 
with a sinusoidal curve y == 1 +  Cos[2 Pi x/L] separating the two. 
 
I want to solve  ...

asked by Physicist https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41581 8 votes

answered by user21 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=18437 8 votes

LaTeX and Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=736

I quite often would like to draw graphics in my LaTeXdocuments using Mathematica. I have encountered three problems. I would like to know if there are any workarounds to these problems

I would ...

asked by Thomas Rot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=227 124 votes

answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 45 votes

How to make a spiroglyphic?]

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=188139

Some (older) members of this group might remember playing vinyl LP records. Recently, at the Abbey Road studio there was a spiroglyphics coloring book for sale. It looks like a nice programming ...

asked by TheDoctor https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2263 13 votes

answered by b3m2a1 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38205 18 votes

How to graph a sphere with cartesian equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=24169

I’m new to Mathematica and I need to ask how to graph a sphere, cylinder, etc.. using cartesian equations.

For example in sphere’s case \(x^2+y^2+z^2=1\)

I tried to use Plot3D but it doesn’t ...

asked by German https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7145 7 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 13 votes

Mathematica Minecraft

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19669

Some time ago I asked myself: with all these great graphics and interactive capabilities of Mathematica, what kinds of 3D games can be implemented in it? And the answer which came to mind is ...

asked by faleichik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=219 163 votes

answered by faleichik https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=219 232 votes

Code that generates a mandala

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=136974

My little brother asked me to print original mandalas for coloring. I would like some idea on how to create them, but without color, so he can color them.

asked by zeros https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26849 69 votes

answered by Anton Antonov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34008 93 votes

Calling Correct Function for Plotting DiracDelta

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3506

I am wondering what is the correct function in Mathematica to plot the true impulse function, better known as the DiracDelta[] function. When using this inside of a function or just the function ...

asked by night owl https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=116 17 votes

answered by Heike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46 19 votes

Solving \(L=\frac {3}{2} \sqrt {4 \pi ^2 A^2+W^2}-\frac {\sqrt {5 W \sqrt {4 \pi ^2 A^2+W^2}+6 \pi ^2 A^2+3 W^2}}{\sqrt {2}}+\frac {3 W}{2}\) for \(W\)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=57763

When I solve the aforementioned equation for \(W\) or \(A\) on Mathematica I get a long and ugly equation in return, namely one of the solutions for \(W\) is: (attempt to read at your own health)

asked by J.D’Almbert ( https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19257 ) 8 votes

answered by Alexei Boulbitch ( https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=788 ) 13 votes

2.33.2 Can you answer these questions?

UnitSimplify rules?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=217164

Code as following:

In[1]:= constants = Quantity /@ {"PlanckConstant", "BoltzmannConstant", "MolarGasConstant"}; 
  Print[UnitSimplify[ 
  UnitConvert[Quantity["AvogadroNumber"]*constants[[2]]]] // N];

asked by ( https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19360 ) 1 vote

How to delete random elements with RandomChoice?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218431

I have a list of prices and a list of dates, but I have 154 more prices than dates. So I want to delete random prices to match both lists, however, every time I run the block of code I get a different ...

asked by trashparticle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=71573 1 vote

settings elements of matrix of functions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=218297

I have a work flow that involves initially specifying a matrix function 
(or a matrix of functions), e.g. 
 
f[x_]:={{Exp[x],Sin[x]},{Cos[x],Log[x]}}

This works well for what I am using it for. I can ...

asked by user3353819 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34650 1 vote