How to unfold/concatenate a 3D Matrix?

I have a 3D matrix of 100x21x100 and I want to perform a vertical unfolding, i.e., to get a 10000x21 matrix.

Thanks for your attention.

Answer 1

[Stephen23]

Making some guesses about the order you want, where A is your array:

B = reshape(permute(A,[1,3,2]),[],21)

[Rafael Borobio Castillo]

it worked perfectly, thanks