1 SelfAdjointEigenSolver<Matrix4f> es; 2 Matrix4f X = Matrix4f::Random(4,4); 3 Matrix4f A = X + X.transpose(); 4 es.compute(A); 5 cout << "The eigenvalues of A are: " << es.eigenvalues().transpose() << endl; 6 es.compute(A + Matrix4f::Identity(4,4)); // re-use es to compute eigenvalues of A+I 7 cout << "The eigenvalues of A+I are: " << es.eigenvalues().transpose() << endl; 8