FastDeploy/third_party/eigen/doc/snippets/ComplexEigenSolver_compute.cpp

MatrixXcf A = MatrixXcf::Random(4, 4);
cout << "Here is a random 4x4 matrix, A:" << endl << A << endl << endl;

ComplexEigenSolver<MatrixXcf> ces;
ces.compute(A);
cout << "The eigenvalues of A are:" << endl << ces.eigenvalues() << endl;
cout << "The matrix of eigenvectors, V, is:" << endl
     << ces.eigenvectors() << endl
     << endl;

complex<float> lambda = ces.eigenvalues()[0];
cout << "Consider the first eigenvalue, lambda = " << lambda << endl;
VectorXcf v = ces.eigenvectors().col(0);
cout << "If v is the corresponding eigenvector, then lambda * v = " << endl
     << lambda * v << endl;
cout << "... and A * v = " << endl << A * v << endl << endl;

cout << "Finally, V * D * V^(-1) = " << endl
     << ces.eigenvectors() * ces.eigenvalues().asDiagonal() *
            ces.eigenvectors().inverse()
     << endl;