Hi,
No, I didn't, as I read in the GHC docs that it is deprecated in favor of
the RULES pragma (I wanted to replace specifically with floatToDouble and
doubleToFloat).
On Wed, Nov 2, 2011 at 5:24 PM, Jean-Marie Gaillourdet
Hi Eugene,
did you try using the SPECIALIZE pragma? It is part of the Haskell 98 and Haskell 2010 specifications.
On 02.11.2011, at 12:14, Eugene Kirpichov wrote:
Yay!!!
I made a small change in Types.chs and got my original cairo-binding-based program to be just as blazing fast. The only problem I have with this is that I used multiparameter type classes.
Dear gtk2hs team! Is it possible to incorporate my changes? I'm pretty sure people will be happy by an order-of-magnitude speedup. Probably the stuff could be wrapped in #define's for those who aren't using GHC and can't use multiparameter type classes?
I am pretty sure I could have done the same with rewrite rules, but I tried for a while and to no avail.
FAILED SOLUTION: rewrite rules cFloatConv :: (RealFloat a, RealFloat b) => a -> b cFloatConv = realToFrac {-# NOINLINE cFloatConv #-} {-# RULES "cFloatConv/float2Double" cFloatConv = float2Double #-} {-# RULES "cFloatConv/double2Float" cFloatConv = double2Float #-} {-# RULES "cFloatConv/self" cFloatConv = id #-}
See [1] in GHC User Guide.
cFloatConv :: (RealFloat a, RealFloat b) => a -> b cFloatConv = realToFrac -- or try fromRational . toRational
{-# SPECIALIZE cFloatConv :: Float -> Double #-} {-# SPECIALIZE cFloatConv :: Double -> Float #-}
I did not try to compile or even benchmark this code. But I think it might help in your case.
Cheers, Jean
[1]: http://www.haskell.org/ghc/docs/latest/html/users_guide/pragmas.html#special...
-- Eugene Kirpichov Principal Engineer, Mirantis Inc. http://www.mirantis.com/ Editor, http://fprog.ru/