Idempotent partition around median of 5?

[Andrei Alexandrescu via Digitalmars-d]

On 2/6/16 9:26 AM, Timon Gehr wrote:
> [1] This seems to be the shortest code that satisfies the specification
> I have given (<=6 comparisons, optimal number of swaps) for permutations
> and that performs all the comparing before all the swapping:

Thanks. Tried this just now, it's better than the pre-discussion 
baselines but Ivan's still beats it (by a little). Then I just tried 
tn's partition5c which beats Ivan's.

I should also add that returns are starting to diminish. Idempotence did 
make a large difference. Then reducing max swaps made a smaller 
difference (at least for the uints I'm working with).

BTW my testbed is a careful implementation of BFPRT on random arrays of 
uint of various sizes.


Andrei