Hi, I am a co-developer of swiginac. The bug is probably there. But, exactly as Alexei said, A-A = 0 is ugly, but, but fixing it would be very difficult (if possible at all). That's why I decided to rewrite the whole GiNaC in python directly: http://code.google.com/p/sympy/ And in SymPy, you can do: In [1]: m = Matrix(2,2,[x,0,0,0]) In [2]: m Out[2]: x 0 0 0 In [3]: m-m Out[3]: 0 0 0 0 In [4]: m+(-m) Out[4]: 0 0 0 0 Ondrej On 3/22/07, Martin Sandve Alnæs <martinal@simula.no> wrote:
2007/3/22, Sheplyakov Alexei <varg@theor.jinr.ru>:
Hello!
On Thu, Mar 22, 2007 at 09:44:03AM +0100, Martin Sandve Alnæs wrote:
If I subtract two equal matrices, I get the scalar 0.
In GiNaC (A-A) is always transformed into 0 (number). I admit this is ugly, but fixing it would be very difficult (if possible at all).
I see.
If I do a+(-b) instead of a-b, I get a zero matrix as wanted.
Interesting. I get zero (a number) in both ways:
Seems like the matrix with zeros only happens when using the swiginac bindings, so techniqually the bug is there.
Thanks for the quick response, anyway.
martin _______________________________________________ GiNaC-list mailing list GiNaC-list@ginac.de https://www.cebix.net/mailman/listinfo/ginac-list