On Sun, Aug 7, 2011 at 5:20 PM, Daniel Fischer
<daniel.is.fischer@googlemail.com> wrote:
On Sunday 07 August 2011, 10:52:20, Max Bolingbroke wrote:
> In short I don't see how to get further without changing the algorithm
> or doing some hacks like manual unrolling. Maybe someone else has some
> ideas?
Well, the C# implementation uses arrays for lookup while the Haskell
version uses list lookups
in (tens !! fromIntegral t) ++ wordify x
and case'd functions
lenTens 0 = 0
lenTens 1 = 3
lenTens 2 = 6
lenTens 3 = 6
lenTens 4 = 5
lenTens 5 = 5
lenTens 6 = 5
lenTens 7 = 7
lenTens 8 = 6
lenTens 9 = 6
wordify is only called once at the end, so that should not have a
measurable impact, but the lenXXXs might.
I'm not sure what
CaseLen.$wlenTens :: GHC.Prim.Int# -> GHC.Prim.Int#
[GblId,
Arity=1,
Str=DmdType L,
Unf=Unf{Src=<vanilla>, TopLvl=True, Arity=1, Value=True,
ConLike=True, Cheap=True, Expandable=True,
Guidance=IF_ARGS [12] 11 0}]
CaseLen.$wlenTens =
\ (ww_shY :: GHC.Prim.Int#) ->
case ww_shY of _ {
__DEFAULT ->
CaseLen.lenTens1
`cast` (CoUnsafe GHC.Types.Int GHC.Prim.Int#
:: GHC.Types.Int ~ GHC.Prim.Int#);
0 -> 0;
1 -> 3;
2 -> 6;
3 -> 6;
4 -> 5;
5 -> 5;
6 -> 5;
7 -> 7;
8 -> 6;
9 -> 6
}
means at a lower level, but it's certainly worth trying out whether an
unboxed array lookup is faster.