I was reading this article on MathWorks about improving MATLAB performance and you will notice that one of the first suggestions is to preallocate arrays, which makes sense. But it also says that preallocating Cell arrays (that is arrays which may contain different, unknown datatypes) will improve performance.

But how will doing so improve performance because the datatypes are unknown so it doesn't know how much contiguous memory it will require even if it knows the shape of the cell array, and therefore it can't preallocate the memory surely? So how does this result in any improvement in performance?

I apologise if this question is better suited for StackOverflow than Programmers but it isn't asking about a specific problem so I thought it fit better here, please let me know if I am mistaken though.

Any explanation would be greatly appreciated :)