vector<vector<double> > matrix_mult(vector<vector<double> >, vector<vector<double> >);
int tred2(vector<vector<double> >&, vector<double>&, vector<double>&);
int qtli(vector<double>&, vector<double>&, vector<vector<double> >&);
vector<vector<double> > matrix_mult(vector<vector<double> >, vector<vector<double> >);
int tred2(vector<vector<double> >&, vector<double>&, vector<double>&);
int qtli(vector<double>&, vector<double>&, vector<vector<double> >&);