Vectorizing this Operation

I have list of random permutations of length 3: [1 0 0], [0 1 0], [0 0 1], [1 1 0], ...

I have matrix of random values from 1 to 6 of size m by n. Where each value indexes a permutation.

I want to obtain the m by 3*n matrix where each index is replaced by its corresponding permutation. Advice?

Answer 1

[Walter Roberson]

It will look something like

reshape(perms(pidx(:),:).',size(pidx,2)*size(perms,2),[]).'

but I didn't bother testing it out to be sure it gets everything in the right place (it's my bedtime.)