[GiNaC-list] 1by1 matrix to scalar

[Felipe Bordeu]

any ideas ?

Thanks.

On 18/06/2010 15:06, Felipe Bordeu wrote:
> Hello,
>
> I have a little problem, I'm dealing functions made of matrix products.
>
> My question is, how can "force"  ginac to convert automatically all 
> the 1by1 matrices to scalars?.
> or do I have to do it manually??
>
> Here is a simple example.
>
> void main2(){
>   ex m1=symbolic_matrix(1, 3, "x");
>   ex m2=symbolic_matrix(3, 1, "y");
>
>   cout <<  m1 << std::endl;
>   cout <<  m2 << std::endl;
>   ex m3 = (m1*m2).evalm();
>   cout << m3 << std::endl;
>   cout << ex_to<matrix>(m3)(0,0)<< std::endl;;
>   ex m4 = m3-ex_to<matrix>(m3)(0,0);
>   cout << m4 << std::endl;
> };
> the output :
>
> [[x0,x1,x2]]
> [[y0],[y1],[y2]]
> [[y1*x1+y2*x2+y0*x0]]
> y1*x1+y2*x2+y0*x0
> -y1*x1+[[y1*x1+y2*x2+y0*x0]]-y2*x2-y0*x0
>
> the last line "should" be zero ?--
>
> thanks
>
> Felipe
>
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-- 

Felipe Bordeu Weldt
Ingénieur de Recherche
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Felipe.Bordeu at ec-nantes.fr
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