Random sampling in Phobos

[Joseph Rushton Wakeling]

On 17/04/12 17:31, Andrei Alexandrescu wrote:
> This would be great, but you'd need to show with benchmarks that the proposed
> implementation does better than the extant one for most cases that matter.

OK, I've uploaded a prototype version in a GitHub repo:
git://github.com/WebDrake/RandomSample.git

This isn't a patch against Phobos, but a copy-paste and rename of the 
RandomSample struct/randomSample functions that lets me do some side-by-side 
comparison to current Phobos implementation.  It does need a fully up-to-date 
DMD, druntime and Phobos to compile.

I've put in place a handful of very simple tests just to give an idea of some of 
the speed differences.  The difference probably isn't so great for most trivial 
use-cases, but if you're doing a LOT of sampling, or you're sampling from a very 
large set of records, the difference becomes quite apparent.

I'm not sure what use-cases you have in mind for the benchmarks -- can you give 
me some idea, so I can go ahead and implement them?

Thanks and best wishes,

     -- Joe