#include <Eigen/Dense>
#include <iostream>

using namespace Eigen;
using namespace std;

int main(int, char**)
{
  cout.precision(3);
  MatrixXi mat(3,3); 
mat << 1, 2, 3,   4, 5, 6,   7, 8, 9;
cout << "Here is the matrix mat:\n" << mat << endl;

// The eval() solves the aliasing problem
mat.bottomRightCorner(2,2) = mat.topLeftCorner(2,2).eval();
cout << "After the assignment, mat = \n" << mat << endl;

  return 0;
}