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.