1MatrixXd A = MatrixXd::Random(3,3); 2MatrixXd B = MatrixXd::Random(3,2); 3cout << "Here is the invertible matrix A:" << endl << A << endl; 4cout << "Here is the matrix B:" << endl << B << endl; 5MatrixXd X = A.lu().solve(B); 6cout << "Here is the (unique) solution X to the equation AX=B:" << endl << X << endl; 7cout << "Relative error: " << (A*X-B).norm() / B.norm() << endl; 8