Daan Leijen daanleijen at xs4all.nl
Tue May 25 17:09:34 EDT 2004

On Tue, 25 May 2004 12:02:22 +0100, Adrian Hey <ahey at iee.org> wrote:

> On Tuesday 25 May 2004 10:25 am, Simon Marlow wrote:
>> Yes, IntMap should get faster lookup.  I looked at the code and managed
>> to make a couple of improvements: adding a 'seq k $' at the beginning of
>> lookup helps, and I fixed a small performance problem with the Word
>> library, but interestingly these don't help the results.  I still get
>> 0.16s for the lookup test, so perhaps it is dominated by something else.
> I think yesterdays changes announced by JP Bernardy probably improve
> matters a lot if there's any truth in my No. of heap records theory.
> Before this change it would have had the same 2 records/tree node
> overhead as FiniteMap/DData.Map.

I can see another speed improvement to lookup too: it now repeatedly
does "fromIntegral" on the keys (via "zero" and "nomatch") maybe
by let-binding and inlining this, we can make it faster. (I have
not done any of this up till now, as it is not resistant to change
but I guess that doesn't matter that much any more.)

I'll tweak JP's latest sources and post them here again, so that
Simon can run his benchmark on it.

All the best,

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