It depends. The point of my videos is to illustrate a concept clearly an concisely. Pre-allocation would be marginally better in a situation like this, but because the matrices are small it would be only a small improvement.

In real code, I would totally pre-allocate if this was a matrix of any real size, but for small ones I might or might not do it. I prefer clarity and brevity most of the time. If speed becomes an issue later, I can easily add that optimization.

Thanks for asking,
Doug

The mat array should be preallocated first don’t you agree?