Associative arrays

[TheFlyingFiddle via Digitalmars-d-learn]

On Monday, 9 November 2015 at 04:52:37 UTC, rsw0x wrote:
> On Monday, 9 November 2015 at 04:29:30 UTC, Rikki Cattermole 
> wrote:
> Fwiw, EMSI provides high quality containers backed by 
> std.experimental.allocator.
> https://github.com/economicmodeling/containers

I have a question regarding the implementation of the 
economicmodeling hashmap. Why must buckets be a power of two? Is 
it to be able to use the: hash & (buckets.length - 1) for index 
calculations or is there some other reason?