[GiNaC-list] 1by1 matrix to scalar

[jros]

This is trivial from the GiNaC tutorial: I suppose you know
about evalm()

Javier


On Wed, 2010-06-23 at 13:19 +0200, Felipe Bordeu wrote:
> 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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> 
>