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

Matthias Reis matthias.reis at biologie.hu-berlin.de
Mon Apr 27 19:15:20 CEST 2015

```Dear Matthias,

thanks a lot for your work. However, I have implemented a numeric
workaround that does not need symbolic integration a few weeks ago.
Since this approach works and I am running out of time with my PhD, I
will unfortunately not be able to look further into ginac. At some point
in the future maybe.

Best regards and thanks again,
Matthias

Am Mon, 27 Apr 2015 16:27:43 +0200
schrieb Matthias Dellweg <dellweg at tp1.uni-duesseldorf.de>:

> 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,
> > >>>>> 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
> >     MR> me maybe) to implement exponentials? What needs to be done?
> >     MR> This feature would be great for me. I just need to
> >     MR> integrate simple 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

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