[GiNaC-list] Not factoring expression
Richard B. Kreckel
kreckel at ginac.de
Mon Feb 16 18:17:31 CET 2009
Hi,
James Jackson wrote:
> I've just started using GiNaC (and very nice it is too!), however I have
> some strange behavior with an expression not being simplified. One
> output of a linear equation solver is the expression:
>
> (C_2*s^2*L_2*V_1+C_2*L_1*C_1*s^4*L_2*V_1+L_1*C_1*s^2*V_1+V_1)*(1+L_1*C_1*s^2+C_2*L_1*s^2+C_2*L_1*C_1*s^4*L_2+C_2*s^2*L_2)^(-1)*V_1^(-1)
>
> What is happening is that the V_1 terms in the first bracket are not
> being factorised, and therefore no cancellation with the final
> (V_1)^(-1) term is occuring. All my symbols are created with a
> SymbolFactory pattern, so I can be sure each V_1 is the same object.
>
> Can anyone suggest why GiNaC isn't simplifying this to cancel the V_1
> terms?
The linear solvers don't cancel common factors in numerator and
denominator. You have to explicitly call normal() on the result in order
to do that.
Bye
-richy.
--
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>
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