1EigenSolver<MatrixXf> es;
2MatrixXf A = MatrixXf::Random(4,4);
3es.compute(A, /* computeEigenvectors = */ false);
4cout << "The eigenvalues of A are: " << es.eigenvalues().transpose() << endl;
5es.compute(A + MatrixXf::Identity(4,4), false); // re-use es to compute eigenvalues of A+I
6cout << "The eigenvalues of A+I are: " << es.eigenvalues().transpose() << endl;
7