[GiNaC-list] products of exponentials

Levi Boyles leviboyles at gmail.com
Thu Dec 8 00:22:59 CET 2011


Hello,

I'm dealing with products of large polynomial exponentials.  However,
whenever a product of two exponential terms appears they are not
"simplified" into an exponential of a sum (unless the exponential args are
numeric).  Is there some way to coerce this to happen?  Specifically I have
a situation like this:

exp(T-t_1)*exp(T-t_2)

and I want something like this:

exp(2T-t_1-t_2)

or even

exp(2T) exp(-t_1) exp(-t_2)


I'm porting some of ginac's functionality to python (using cython), and
I've been accessing ginac through that, so it's possible it's a bug on my
side.  However, I've tried to get the desired behavior in ginsh with no
luck, so I'm guessing the default behavior is to not simplify products of
exponentials.  I've also tried creating a possymbol called "e" and simply
raising it to the needed power, but this has the same behavior as the exp
function.  I've been using ginac1.6.1

Thanks,
Levi
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