int LoadMatrixFromTxt(const char* filename, vnl_matrix<double>& matrix) { std::ifstream infile(filename, std::ios_base::in); if (infile.is_open()) { if (matrix.read_ascii(infile)) { return matrix.rows(); } else { std::cerr << "unable to parse input file " << filename << " as a matrix." << std::endl; return -1; } } else { std::cerr << "unable to open model file " << filename << std::endl; return -1; } }