|  | #include <Eigen/Core> | 
|  | #include <iostream> | 
|  | using namespace std; | 
|  | using namespace Eigen; | 
|  |  | 
|  | template<typename Derived> | 
|  | const Reshaped<const Derived> | 
|  | reshape_helper(const MatrixBase<Derived>& m, int rows, int cols) | 
|  | { | 
|  | return Reshaped<const Derived>(m.derived(), rows, cols); | 
|  | } | 
|  |  | 
|  | int main(int, char**) | 
|  | { | 
|  | MatrixXd m(3, 4); | 
|  | m << 1, 4, 7, 10, | 
|  | 2, 5, 8, 11, | 
|  | 3, 6, 9, 12; | 
|  | cout << m << endl; | 
|  | Ref<const MatrixXd> n = reshape_helper(m, 2, 6); | 
|  | cout << "Matrix m is:" << endl << m << endl; | 
|  | cout << "Matrix n is:" << endl << n << endl; | 
|  | } |