hughperkins:
>
> Hey, guys, I just realized this test is not really fair!
> I've been using the Microsoft .Net compiler ,which is a
> proprietary closed-source compiler.
> To be fair to Haskell, we should probably compare it to
> other open source products, such as g++ and mono?
> Here are the timings ;-)
> Haskell
> ======
> J:\dev\haskell>ghc -O2 -o primechaddai.exe PrimeChaddai.hs
> J:\dev\haskell>primechaddai
> number of primes: 664579
> Elapsed time: 26.234
Oh, I think we can do a bit better than that....
See below.
> g++
> ===
> J:\dev\test\testperf>g++ -O2 -o prime.exe prime.cpp
> J:\dev\test\testperf>prime
> number of primes: 664579
> elapsed time: 0.984
> mono
> ====
> J:\dev\test\testperf>erase primecs.exe
> J:\dev\test\testperf>gmcs primecs.cs
> J:\dev\test\testperf>mono primecs.exe
> number of primes: 664579
> elapsed time: 0,719
> Microsoft C#
> =========
> J:\dev\test\testperf>csc /nologo primecs.cs
> J:\dev\test\testperf>primecs
> number of primes: 664579
> elapsed time: 0,6875
> Not only does mono come close to the Microsoft .Net time,
> both mono and Microsoft .Net are faster than g++ ;-) and
> whack Haskell.
I reimplemented your C++ program, could you time this please?
{-# OPTIONS -O2 -fbang-patterns #-}
import Data.Array.IO
import Data.Array.Base
import System
import Control.Monad
import Data.Bits
import Text.Printf
main = sieve 10000000
sieve n = do
a <- newArray (2,n) True :: IO (IOUArray Int Bool) -- an array of Bool
r <- go a n 2 0
printf "Primes up to %8d %8d\n" (n::Int) (r::Int) :: IO ()
go !a !m !n !c
| n == m = return c
| otherwise = do
e <- unsafeRead a n
if e then let loop !j
| j < m = do
x <- unsafeRead a j
when x (unsafeWrite a j False)
loop (j+n)
| otherwise = go a m (n+1) (c+1)
in loop (n `shiftL` 1)
else go a m (n+1) c
On my machine:
$ ghc -o primes primes.hs
$ time ./primes
Primes up to 10000000 664579
./primes 0.52s user 0.01s system 99% cpu 0.533 total
0.5s. So rather fast.
Enjoy!
Don
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