On Oct 13, 2007, at 6:52 , ntupel wrote:
On Fri, 2007-10-12 at 20:25 -0700, Stefan O'Rear wrote:
On Sat, Oct 13, 2007 at 12:09:57AM +0200, ntupel wrote:
setup :: (Ord a, IArray a2 a, IArray a1 e, Num a) => [e] -> [a] -
> (a1 Int e, a1 Int e, a2 Int a)
calcAlias :: (Ord e, Num e, IArray a e, Ix i, IArray a2 e1,
IArray a1 e1) => a2 i e1 -> a1 i e1 -> a i e -> [i] -> [i] -> (a1
i e1, a i e)
next :: (IArray a2 e1, IArray a e1, Ord e, IArray a1 e, RandomGen
t, Random e) => (a Int e1, a2 Int e1, a1 Int e) -> t -> (e1, t)
randomList :: (Random e, RandomGen t1, IArray a2 e, Ord e, IArray
a t, IArray a1 t) => (a Int t, a1 Int t, a2 Int e) -> t1 -> [t]
...
I would try specializing to StdGen, UArray, and Int, for RandomGen,
IArray, and Random respectively.
Thanks for your reply Stefan. Unfortunately I could measure only a
relatively small improvement by changing to concrete types, e.g. using
(...)
COST CENTRE MODULE %time %alloc
random Random 60.0 54.5
randomR Random 20.0 23.3
next Random 17.5 17.0
main Main 1.9 2.5
randomList Random 0.6 2.8
Now you need to start forcing things; given laziness, things tend to
only get forced when in IO, which leads to time being accounted to
the routine where the forcing happened. If random / randomR are
invoked with large unevaluated thunks, their forcing will generally
be attributed to them, not to functions within the thunks.
(Yes, this means profiling lazy programs is a bit of a black art.)
--
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED]
system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED]
electrical and computer engineering, carnegie mellon university KF8NH
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