[Haskell-cafe] [Somewhat OT] Speed

Christopher Lane Hinson lane at downstairspeople.org
Wed Oct 29 17:05:34 EDT 2008


>
> OK, well thanks for the info.
>
> I'm not really interested in getting down to instruction-level scheduling. I 
> just want to know, at a high level, will implementing my algorithm in integer 
> arithmetic rather than floating-point make a measurable difference to overall 
> program speed.
>
> Actually, thinking about it, I suppose the killer question is this: Does 
> changing between different numer representations make any measurable 
> performance difference at all, or are Haskell programs dominated by cache 
> misses?

A casual inspection won't reveal much difference between 
Int/Integer/Float/Double.

Rational is the only thing I've seen that's very slow, and you can hit 
that accidently using some of the polymorphic functions, e.g. realToFrac 
with RULES off.  Or divMod' even with RULES on.

--Lane


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