First thing I noticed, how about removing the sqrt in isInCircle: isInCircle :: (Floating a, Ord a) => (a,a) -> Bool isInCircle (x,y) = x*x + y*y <= 1.0 But you can remove sqrt from the C++ implementation as well, so it only improves the relative performance if the C++ implementation of sqrt is worse than its Haskell counterpart. Regards, Thomas haskell@kudling.de wrote:
Hi,
i have compared a C++ implementation with a Haskell implementation of the Monte Carlo Pi approximation:
http://lennart.kudling.de/haskellPi/
The Haskell version is 100 times slower and i wonder whether i do something obvious wrong.
Profiling says that the majority of the time is spend in "main". But i have no idea where.
Can someone give me a hint?
Thanks, Lenny
individual inherited COST CENTRE MODULE no. entries %time %alloc %time %alloc
MAIN MAIN 1 0 0.0 0.0 100.0 100.0 main Main 254 1 88.1 90.8 100.0 100.0 monteCarloPi Main 255 1 0.6 1.1 11.9 9.2 pairs Main 257 10000000 0.7 1.4 0.7 1.4 countHits Main 256 10000001 4.2 2.9 10.6 6.7 accumulateHit Main 258 27852236 3.0 2.3 6.4 3.8 isInCircle Main 259 30000000 3.3 1.5 3.3 1.5 CAF:lit_r1A7 Main 248 1 0.0 0.0 0.0 0.0 isInCircle Main 260 0 0.0 0.0 0.0 0.0 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe