Eigen: creating a 3D array with a function

Question

I've just started using Eigen for my project, and I realized it does not support 3D arrays. So I've decided to make a function which gets an array type pointer and initialize Eigen 3D array. '''

ArrayXXf* Array3DInit (ArrayXXf *&array, int dimension[], float val){
    array = new ArrayXXf [dimension[0]];
    for (int i=0; i<dimension[0]; i++){
        array[i] = (ArrayXXf::Ones(dimension[1], dimension[2])*val);
    }

    return array;
}

'''

Since we are dynamically allocating 2D arrays, I created another function that deletes the initialized 3D array as follow,

void Array3Ddel (ArrayXXf *&array){
    delete []array;
}

Question is, is this an OK way to create/delete a 3d array with Eigen?

Is there a standardized way to use 3D arrays with Eigen?

Thank you very much.

Answer 1

For me the easiest and least error prone way of doing doing this is using std::vector:

#include <Eigen/StdVector>
using Matrix = Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic>;
using Vector = std::vector<Matrix, Eigen::aligned_allocator<Matrix>>;

Matrix m(2,2);
m << 1.0, 2.0, 3.0, 4.0;

Vector vec;
vec.push_back(m);

To use std::vector with Eigen the above include and an aligned allocator must be used, see here.