VConcat many matrices together
Concatenating matrices in a loop slows down with loop iterations.
For example this pseudocode:
OutputM = [];
for( i=1, i<=N, i++,
// do some calculations, generate a matrix of results, call it, ThisM
OutputM |/ = ThisM
);
If I do the above, then as N increases, the VConcat line gets slower and slower with every iteration.
Note that each iteration produces a matrix with same number of columns...