How to find all possible 8x8 submatrices of a 13x8 matrix?

I have martrix A with size 13x8, and I want to find a list of all the possible 8x8 submatrices combinations of matrix A.

The number of submatrices possible is 13C8 = 1287

Any help is appreciated!

Answer 1

[Torsten]

r = nchoosek(1:13,8);
A = rand(13,8);
for i = 1:size(r,1)
    B(:,:,i) = A(r(i,:),:);
end
size(B)

ans = 1×3

8 8 1287

[HN]

Thank you so much for your help. It worked!

Answer 2

[Matt J]

Using this File Exchange tool set,

https://www.mathworks.com/matlabcentral/fileexchange/115340-block-transposition-permutation-and-reshaping-of-arrays

A=rand(13,8);

submatrices = blkReshape( A(nchoosek(1:13,8)', : )   ,[8,8],1,1,[]);

whos submatrices

Name Size Bytes Class Attributes

submatrices 8x8x1287 658944 double

[HN]

Thank you so much for your reply. I tried it but it's mixing numbers randomly from the matrix. I wanted to get all the combinations from choosing 8 rows out of 13 while keeping the elements in each row fixed.

I appreciate your help!

[Matt J]

Make sure you have my latest version.

[HN]

Sure, will check. Thank you!