1#include <iostream>
2#include <Eigen/Dense>
3
4using namespace std;
5using namespace Eigen;
6
7int main()
8{
9   Matrix2f A;
10   A << 1, 2, 2, 3;
11   cout << "Here is the matrix A:\n" << A << endl;
12   SelfAdjointEigenSolver<Matrix2f> eigensolver(A);
13   if (eigensolver.info() != Success) abort();
14   cout << "The eigenvalues of A are:\n" << eigensolver.eigenvalues() << endl;
15   cout << "Here's a matrix whose columns are eigenvectors of A \n"
16        << "corresponding to these eigenvalues:\n"
17        << eigensolver.eigenvectors() << endl;
18}
19