#include <utility>#include <mtl/matrix.h>using namespace mtl;using namespace std;intmain() {  typedef matrix<pair<double,double>,                 rectangle<>,                  array <compressed<> >,                 row_major >::type Matpair;  int m = 4;  int n = 4;  Matpair BPair(m, n);  BPair(0,2) = make_pair(1.0,1.5);  BPair(1,2) = make_pair(2.0,2.5);  BPair(2,3) = make_pair(4.0,4.5);    int i, k ;  for(i=0 ; i < m ; i++) {    for(k=0 ; k < n ; k++) {      pair<double,double> ik = BPair(i,k);      std::cout << "I = " << i << " K = " << k 		<< " " <<  ik.first 		<< " " <<  ik.second 		<< std::endl;    }  }    return 0;}