This note describes all the steps to use Python inside Latex. The directions are based on using Linux, since this is the system I tried this on.
Using texlive 2020, this package (pythontex) is already there. There is not additional installation needed. Once you install texlive itself, then you have this package.
Here is the most simple tex file that uses python
\documentclass[11pt]{article}% \usepackage{pythontex} \begin{document} This document uses Python \end{document}
Now comes the tricky part. To compile it, we have to do the following commands
pdflatex foo.tex /usr/local/texlive/2022/texmf-dist/scripts/pythontex/pythontex.py foo.tex
Which prints on the screen this
>/usr/local/texlive/2022/texmf-dist/scripts/pythontex/pythontex.py python_file.tex This is PythonTeX 0.17 -------------------------------------------------- PythonTeX: python_file - 0 error(s), 0 warning(s)
If you get an error ModuleNotFoundError: No module named 'pygments' then try the
following to install pygments: pip install pygments first.
Now need to compile the latex file on more time
pdflatex foo.tex
We have to run the above 3 commands each time. On my installation of texlive 2022, the
script pythontex.py was not already in the path, so instead of keep typing the above long
command each time, I added an alias to my bashrc
vi $HOME/.bashrc #add this line below to the file alias PYX=/usr/local/texlive/2022/texmf-dist/scripts/pythontex/pythontex.py #after exiting vi, typed source $HOME/.bashrc
So now I can write (less typing) the following
pdflatex foo.tex PYX foo.tex pdflatex foo.tex
Or you can add it to the path. You must have python itself installed. Version 2.7 or better, else none of the above will work.
In the above example, we did not do anything interesting. Let us now make a python variable, raise it to the power 2, and show the result in Latex
\documentclass[11pt]{article}% \usepackage{pythontex} \usepackage{nopageno} \begin{document} \begin{pyconsole} x = 987.27 x = x**2 \end{pyconsole} The variable is $x=\pycon{x}$ \end{document}
Which produces the following PDF file when compiled
Here is screen shot of the above
In this example we will call Python to do symbolic computation, which is integrating a
function, then obtain the latex back of the result. For this sympy is used inside
Python.
Create Latex file like this
\documentclass[11pt]{article}% \usepackage{pythontex} \usepackage{nopageno} \begin{document} \begin{pycode} from sympy import * x=symbols('x') result = latex(integrate("(1+x)**(1/2)",x)) \end{pycode} The result of integrating $\int \sqrt{ 1+x } \, dx$ is given by $\py{result}$ \end{document}
Now compile using the same commands as first example above
pdflatex foo.tex /usr/local/texlive/2022/texmf-dist/scripts/pythontex/pythontex.py foo.tex pdflatex foo.tex
Which produces the following PDF file when compiled
Here is screen shot of the above
In this example, we make a small function inside pycode which takes one argument which is
string that represents the integrand to integrate and second argument which is the
integration variable.
Create Latex file like this
\documentclass[11pt]{article}% \usepackage{amsmath} \usepackage{pythontex} \usepackage{nopageno} \begin{document} \begin{pycode} from sympy import * def int(theIntegrand,var): var = symbols(var) anti = integrate(theIntegrand,var) return latex(anti) \end{pycode} The result of integrating $\int \frac{1}{\sqrt{ 1+x }} \, dx$ is given by $\py{int("1/(1+x)**(1/2)","x")}$ Here is some list of integrations to do \begin{align*} \int \frac{1}{\sqrt{ 1+x }} \, dx &= \py{int("1/(1+x)**(1/2)","x")} \\ \int \sin x \, dx &= \py{int("sin(x)","x")} \\ \int x \sin x \, dx &= \py{int("x*sin(x)","x")} \\ \int x^2 \sin x \, dx &= \py{int("x**2 * sin(x)","x")} \\ \int x e^{2 x} \, dx &= \py{int("x*exp(2*x)","x")} \\ \int \frac{1}{1+u} \, du &= \py{int("1/(1+u)","u")} \\ \end{align*} \end{document}
Compiling again using the same commands as the above examples
pdflatex foo.tex /usr/local/texlive/2022/texmf-dist/scripts/pythontex/pythontex.py foo.tex pdflatex foo.tex
Produces the following PDF file
Here is screen shot of the above
In this example, we make a small function inside pycode which takes and ode to solve, using
different initial conditions.
Create Latex file like this
\documentclass[11pt]{article}% \usepackage{amsmath} \usepackage{pythontex} \usepackage{nopageno} \begin{document} \begin{pycode} from sympy import * def solveODE(ode,y,x): x = Symbol(x) y = Function(y) lhs,rhs = ode.split('=') ode = Eq(S(lhs),S(rhs)) sol = dsolve(ode,y(x)) return latex(sol) def solveODEwithIC(ode,y,x,ic): x = Symbol(x) y = Function(y) lhs,rhs = ode.split('=') ode = Eq(S(lhs),S(rhs)) sol = dsolve(ode,y(x),ics= S(ic) ) return latex(sol) \end{pycode} Given the first order differential equation $y'(x)=1+2 x$, it has the solution \[ \py{solveODE("Derivative(y(x),x)=1+2*x","y","x")} \] % When the initial conditions are $y(0)=3$, then the solution becomes \[ \py{solveODEwithIC("Derivative(y(x),x)=1+2*x","y","x","{y(0):3}")} \] We can also solve second order ODE in Latex. For example, given the ode $y''(x)+3 y(x)=1+2 x$ then its solution is \[ \py{solveODE("Derivative(y(x),x,x)+y(x)=1+2*x","y","x")} \] The above solution with initial conditions $y(0)=1$ and $y'(0)=0$ is given by \[ \py{solveODEwithIC("Derivative(y(x),x,x)+y(x)=1+2*x","y","x","{y(0):1,y(x).diff(x).subs(x, 0): 0}")} \] \end{document}
Compiling again using the same commands as the above examples produces the following PDF file
Here is screen shot of the above
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