MATLAB: Conv2 ‘valid’ implementation

Question

I need to implement the conv2 function for a the HDL coder since it's not supported, I believe that I have the main function down, what I'm struggling with is the implementation of conv2 'valid' which is described in the documentation with — Returns only parts of the convolution that are computed without zero-padded edges-

The code for conv2 is the one I'm sharing, any help would be appreciated.

function B = convolve(A, k)
[r, c] = size(A);
[m, n] = size(k);
h = rot90(k, 2);
center = floor((size(h)+1)/2);
left = center(2) - 1;
right = n - center(2);
top = center(1) - 1;
bottom = m - center(1);
Rep = zeros(r + top + bottom, c + left + right);
for x = 1 + top : r + top
  for y = 1 + left : c + left
      Rep(x,y) = A(x - top, y - left);
  end
end
B = zeros(r , c);
for x = 1 : r
  for y = 1 : c
      for i = 1 : m
          for j = 1 : n
              q = x - 1;
              w = y -1;
              B(x, y) = B(x, y) + (Rep(i + q, j + w) * h(i, j));
          end
      end
  end
end

Answer 1

as mentioned by Bharath, it is more efficient to use Simulink model instead of the MATLAB code to implement the conv2d function. Here I post the link of the Simulink model, which uses the image filer from Vision HDL toolbox to implement conv2 function.

In this model, image filter uses 'same' instead since it is more widely used in deep learning.