1#include <iostream>
2#include <Eigen/Dense>
3
4using namespace std;
5using namespace Eigen;
6
7int main()
8{
9  Eigen::MatrixXf m(2,4);
10  Eigen::VectorXf v(2);
11
12  m << 1, 23, 6, 9,
13       3, 11, 7, 2;
14
15  v << 2,
16       3;
17
18  MatrixXf::Index index;
19  // find nearest neighbour
20  (m.colwise() - v).colwise().squaredNorm().minCoeff(&index);
21
22  cout << "Nearest neighbour is column " << index << ":" << endl;
23  cout << m.col(index) << endl;
24}
25