I just download boost and tried to get a hang of it by running examples out of the doc page. But I am not sure if these examples are ready to run or simply like a pseudo-code? A point in the case: This simple matrix example int main () { using namespace boost::numeric::ublas; matrix<double> m (3, 3); for (int i = 0; i < m.size1 (); ++ i) for (int j = 0; j < m.size2 (); ++ j) m (i, j) = 3 * i + j; std::cout << m << std::endl; } I copied it and added the following includes: #include <boost/numeric/ublas/matrix.hpp> #include <iostream> But the compiler (VC7) flag an error on cout. So is this line " std::cout << m << std::endl;" supposed to work, or it is a pseudo-code. Thanks. J-S Lin