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

int main()
{
  Eigen::ArrayXXf  m(2,2);
  
  // assign some values coefficient by coefficient
  m(0,0) = 1.0; m(0,1) = 2.0;
  m(1,0) = 3.0; m(1,1) = m(0,1) + m(1,0);
  
  // print values to standard output
  std::cout << m << std::endl << std::endl;
 
  // using the comma-initializer is also allowed
  m << 1.0,2.0,
       3.0,4.0;
     
  // print values to standard output
  std::cout << m << std::endl;
}