text: Hi Marco, On Tue, Jun 28, 2005 at 04:05:46PM -0300, mdias at ift.unesp.br wrote: > I am tryng to solve a linear system with lsove(), with many variables > being zero, so lsolve() tell that is indeterminate, but some of these > entries are of interest. > So, I am looking for matrix::solve and construct a matrix to solve this. > Somebody have a piece of code how to make a linear system a matrix to > matrix::solve ? I don't completely understand your question concerning these "entries of interest", but maybe you want to have something like this: #include <iostream> using namespace std; #include <ginac/ginac.h> using namespace GiNaC; int main() { symbol f1("f1"), f2("f2"); symbol A("A"), B("B"); matrix M(2, 2, lst(f1, f1*f2, 0, f2)); matrix x(2, 1, lst(A, B)); matrix b(2, 1, lst(5, 10)); // M x = b matrix result = M.solve(x, b); cout << result << endl; return 0; } Just a small example that can easily be adapted to bigger systems. Regards, Jens