6.66 Assume a constant (3.2.00)

6.66.1 Mohamad Saad

I would like to assume a parameter as a constant using MAPLE V R5 I used the following:

> assume(L, constant); 
> type(L, constant); 
 
                                false 
 
> whattype(L); 
 
                                symbol
 

how can I assume a constant

6.66.2 Dr Francis J. Wright (4.2.00)

Here is one possible solution (in Maple V R5.1, but I think this has worked in most previous releases of Maple V):

> constants := L, constants; 
 
   constants := L, false, gamma, infinity, true, Catalan, FAIL, Pi 
 
> type(L, constant); 
 
                                 true
 

6.66.3 Dr Francis J. Wright (4.2.00)

Here is one possible solution (in Maple V R5.1, but I think this has worked in most previous releases of Maple V):

> constants := L, constants; 
 
   constants := L, false, gamma, infinity, true, Catalan, FAIL, Pi 
 
> type(L, constant); 
 
                                 true
 

6.66.4 Robert Israel (4.2.00)

There is a global variable "constants" that contains all names that Maple knows as symbolic constants. To make L a constant, you just append it to this variable’s value:

> constants:= constants, L; 
 
> type(L, constant); 
 
                          true
 

If you want "evalf" to give L a numerical value, you can assign that to `evalf/constant/L`. For example:

> `evalf/constant/L`:= 1.2345; 
> evalf(2+L); 
 
                          3.2345
 

I get as result: 2. + L. As stated in the help page of evalf you should define `evalf/constant/L` as a procedure. If I do so: `evalf/constant/L` := proc() 1.2345 end: I get the above mentioned result for evalf(2+L). (U. Klein)

6.66.5 Colin Birch (7.2.00)

The error is that assume fixes properties of variables and relationships between them. It cannot affect types. The correct syntax for checking properties is:

> is(L,constant); 
 
                                 true
 

The confusion was caused because, as well as the property constant, there is also a type constant, which seems to include the type numeric and any names held within the global variable constants.

Thus it is possible to give a name or symbol the type constant, using a command like:

> constants := constants,myconstant;
 

I don’t know what the benefit of doing this is.

There are other properties and types that share names, such as integer.

I hope this helps, but I am not sure what significance the property constant has in Maple. Perhaps the question should be "Why do you want to assume that L is constant?"