[Haskell-cafe] GHC predictability
andrewcoppin at btinternet.com
Wed May 14 14:25:47 EDT 2008
Brandon S. Allbery KF8NH wrote:
> On 2008 May 13, at 17:01, Andrew Coppin wrote:
>> That definition of mean is wrong because it traverses the list twice.
>> (Curiosity: would traversing it twice in parallel work any better?)
>> As for the folds - I always *always* mix up
> It might work "better" but you're still wasting a core that could be
> put to better use doing something more sensible. It's pretty much
> always best to do all the calculations that require traversing a given
> list in a single traversal.
Yeah, you're probably right there. I mean, with sufficient inlining,
maybe you would end up with a loop that doesn't even construct any
heap-allocated list nodes, just adds up the integers as fast as it can
On the other hand, N(N+1)/2N is probably even faster! ;-) So I guess
it's kinda of a daft example...
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