.dup on an array of BitArray not duplicating

[Chris Cain]

On Tuesday, 15 May 2012 at 20:50:27 UTC, ixid wrote:
> So if that will not work how would I efficiently copy an array 
> of
> BitArray? Looping through each bit is very slow. An array of 
> bool
> arrays is fine but I want to try to reduce the memory needed for
> memoization of an algorithm.

That wouldn't be looping through each bit. That would be looping 
through each BitArray which contain multiple bits.

In other words, that's still efficient enough. Ideally if you 
know exactly how many bits you need (and it doesn't change), you 
could write your own struct that doesn't use the indirection 
(would use a static array) to get maximum performance and 
maximize the compression. However, many argue that's premature 
optimization ... but I think it's okay if you're trying to learn 
how to push the boundaries of the optimization of your algorithm.

Also, Array!bool is smart ... it compacts the bools down like 
BitArray does. I'm not sure which would be preferable, but they 
both operate somewhat similarly. For what it's worth, it appears 
Array!bool is newer and uses Ranges.