00001 SelfAdjointEigenSolver<MatrixXf> es(4); 00002 MatrixXf X = MatrixXf::Random(4,4); 00003 MatrixXf A = X + X.transpose(); 00004 es.compute(A); 00005 cout << "The eigenvalues of A are: " << es.eigenvalues().transpose() << endl; 00006 es.compute(A + MatrixXf::Identity(4,4)); // re-use es to compute eigenvalues of A+I 00007 cout << "The eigenvalues of A+I are: " << es.eigenvalues().transpose() << endl;