[GiNaC-devel] Powers of exponents

[Richard B. Kreckel]

Dear Vladimir,

Vladimir V. Kisil wrote:
> 		I noticed that exp() functions is not aware of power()
>   method. As a results simple things like pow(exp(a), 2) are not
>   simplified to exp(2*a). I am attaching the corresponding patch.

The rewriting rule pow(exp(x),a) -> exp(a*x) is not correct in the 
general complex case. Consider a=1/2 and x=-I*Pi, for instance. This is 
because, generally, log(exp(x)) -> x is not correct.

GiNaC is very careful about *not* doing such simplifications that are 
not guaranteed to be correct, even in the general complex case. Maybe 
you are unaware of this file 
<http://www.ginac.de/ginac.git?a=blob;f=doc/powerlaws.tex;h=ade0547d048a51f65f414c08416a3979ea885ee8;hb=master>.

Can you fix your patch to only do this simplification when it cannot be 
wrong?

Best wishes
    -richy.
-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>