#include "mtl/matrix.h"#include "mtl/mtl.h"#include "mtl/utils.h"  #include "mtl/linalg_vec.h"/*  Sample output:  A =  3x3  [  [1,0,2],  [0,3,0],  [0,4,5]  ]  x =  [1,2,3,]  y =  [1,1,1,]  Ax + y =[17,15,49,]   */using namespace mtl;typedef matrix< double, rectangle<>, compressed<>, row_major>::type Matrix; typedef dense1D<double> Vec;intmain(){  const int matrix_size=3;  Matrix A(matrix_size,matrix_size);  Vec y(matrix_size,1),x(matrix_size);  double alpha=2, beta=3;  int i;  //make A  A(0,0) = 1;  A(0,2) = 2;  A(1,1) = 3;  A(2,1) = 4;  A(2,2) = 5;  //make x  for (i=0;i<matrix_size;++i)    x[i]=i+1;  std::cout << "A =" << std::endl;  print_all_matrix(A);  std::cout << "x =" << std::endl;  print_vector(x);  std::cout << "y =" << std::endl;  print_vector(y);  mult(A,scaled(x,alpha),scaled(y,beta),y);  std::cout << "A*3x + 2y =";  print_vector(y);}