[GiNaC-devel] [GiNaC-list] Symbolic Integration of exponential functions

[Matthias Dellweg]

Am Mon, 27 Apr 2015 11:37:39 +0100
schrieb "Vladimir V. Kisil" <kisilv at maths.leeds.ac.uk>:

> 	Dear All,
> 
> 	What is easy to do is to add to function class a primitive
>   feature analogously to their knowledge of derivatives. Then,
>   integral::eval_integ() may call such methods to evaluate simple
>   integrals of plain functions.
> 
>   If this looks reasonable to be included in GiNaC, then I may write
>   such a patch.
> 
>   Best wishes,
>   Vladimir
> >>>>> On Sat, 14 Mar 2015 17:35:10 +0100, Matthias Reis
> >>>>> <matthias.reis at biologie.hu-berlin.de> said:  
> 
>     MR> Dear all, as far as I understand, ginac cannot integrate
>     MR> anything other than polynomials. How hard would it be (for me
>     MR> maybe) to implement exponentials? What needs to be done? This
>     MR> feature would be great for me. I just need to integrate simple
>     MR> e^{x * constant} terms.  
> 
>     MR> Best regards, Matthias

Dear Matthias,
i have an implementation ready that integrates expressions like
step(x-a)*x^5*exp(b*x).
You can find it at https://bitbucket.org/mdellweg/ginac.git .
It just can not be done in the way described above, since it needs to
know stuff outside of exp(...).
I would love to hear comments on this.
Kindest regards, Matthias