Simon Marlow simonmar at microsoft.com
Mon May 17 14:37:28 EDT 2004

On 14 May 2004 18:17, Christian Maeder wrote:

> Simon Marlow wrote:
>>> "FiniteMap Int a" performs better than "Map Int a", but not as good
>>> as "IntMap a", but the differences are unimportant for us.
>> How much better?  I'm not keen to import something that's going to
>> degrade performance of existing code noticeably.
> Ok, I'll send you numbers (later). Are you going to reimplement
> FiniteMap via DData.Map (or how could existing code suffer)?

Sorry, I should have been clearer.  I mean that programmers who migrate
code to Data.Map will see a performance loss; that's something I'd like
to avoid.  Furthermore, there shouldn't be any need for Map to be slower
than FiniteMap.

A 10% loss in performance for FiniteMap isn't going to show up in many
profiles, but it'll cause a performance degradation in *lots* of
applications, so fixing it is worthwhile.  Indeed, we should take the
opportunity to see if the code can be tuned any further and improve on
the performance of FiniteMap.


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