Question

I have a 40×16 matrix or 8 5×16 one below the other i.e. aligned vertically.
I want to get a 5×128 matrix from that such that I align the 8 5×16 matrices horizontally.
is there an efficient/quicker (rather than the hardcoded for loops) way to do this?

I want the individual 5×16 matrices intact.

Answer 1

This should work. Suppose your matrix is A (40×16).

Here’s a way using reshape:

m = 5; n = 8; p = 16;
B = reshape(permute(reshape(A', p, m, n), [2 1 3]), m, n*p);

B will have your eight 5×16 matrices next to each other, intact.

And here’s a way without reshape:

m = 5; n = 8;
B = cell2mat(arrayfun(@(i) A(m*(i-1)+1:m*i, :), 1:n, 'UniformOutput', false));