Re: [eigen] Dynamic memory allocation with Matrix::corner ?

[Jitse Niesen <jitse@xxxxxxxxxxxxxxxxx>]

On Thu, 21 Jan 2010, hamelin.philippe@xxxxxxx wrote:

> I just want to make sure that this code doesn't generate dynamic memory 
> allocation :
>
>
> Matrix<double, 6, 6> large;
> Matrix<double, 3, 3> small;
>
> large.corner(Eigen::TopLeft, 3, 3) = small;

It does not. You can check that by compiling and running the program 
below (I saw this trick in test/nomalloc.cpp).

Jitse




// discard stack allocation as that too bypasses malloc
#define EIGEN_STACK_ALLOCATION_LIMIT 0
// any heap allocation will raise an assert
#define EIGEN_NO_MALLOC

#include <Eigen/Core>

using Eigen::Matrix;

int main()
{
  Matrix<double, 6, 6> large;
  Matrix<double, 3, 3> small;
  large.corner(Eigen::TopLeft, 3, 3) = small;
}