performance measurements
Each table row shows performance measurements for this Haskell GHC program with a particular command-line input value N.
| N | CPU secs | Elapsed secs | Memory KB | Code B | ≈ CPU Load |
|---|
Read the ↓ make, command line, and program output logs to see how this program was run.
Read n-body benchmark to see what this program should do.
n-body Haskell GHC #2 program source code
{-# OPTIONS -funbox-strict-fields -fexcess-precision #-} {-# LANGUAGE BangPatterns #-} -- -- The Computer Language Benchmarks Game -- http://shootout.alioth.debian.org/ -- -- Contributed by Olof Kraigher and Don Stewart. -- -- To be compiled with: -- -- -O2 -fvia-C -optc-O3 -- -- Don't enable -optc-mfpmath=sse -optc-msse2, this triggers a gcc bug on x86 -- import Foreign import Foreign.Storable import Foreign.Marshal.Alloc import Data.IORef import Control.Monad import System import Text.Printf main = do n <- getArgs >>= readIO.head initialize offset_momentum energy 0 planets >>= printf "%.9f\n" replicateM_ n (advance planets) energy 0 planets >>= printf "%.9f\n" offset_momentum = do m <- foldr (.+.) (Vec 0 0 0) `fmap` (mapM momentum . take (nbodies - 1) . iterate next $ next planets) setVec (vel planets) $ (-1/solar_mass) *. m where momentum !p = liftM2 (*.) (mass p) (getVec (vel p)) energy :: Double -> Ptr Double -> IO Double energy !e p | p == end = return e | otherwise = do p1 <- getVec (pos p) v1 <- getVec (vel p) m1 <- mass p e <- energy2 p1 m1 e (next p) energy (e + 0.5 * m1 * magnitude2 v1) (next p) energy2 !p1 !m1 e p = go e p where go !e p | p == end = return e | otherwise = do p2 <- getVec (pos p) v2 <- getVec (vel p) m2 <- mass p let distance = sqrt . magnitude2 $ p1 .-. p2 go (e - m1 * m2 / distance) (next p) advance :: Ptr Double -> IO () advance !p1 = when (p1 /= end) $ do pos1 <- getVec $ pos p1 m1 <- mass p1 go_adv p1 pos1 m1 (next p1) advance (next p1) go_adv !p1 pos1 m1 p2 = go p2 where go !p2 | p2 /= end = do pos2 <- getVec (pos p2) m2 <- mass p2 let difference = pos1 .-. pos2 distance = sqrt (magnitude2 difference) magnitude = delta_t / (distance * distance * distance) mass_magn = magnitude *. difference (vel p1) -= m2 *. mass_magn (vel p2) += m1 *. mass_magn go (next p2) | otherwise = do v1 <- getVec (vel p1) p1 += delta_t *. v1 {-# INLINE go_adv #-} ------------------------------------------------------------------------ planets :: Ptr Double planets = unsafePerformIO $ mallocBytes (7 * nbodies * sizeOf (undefined :: Double)) nbodies :: Int nbodies = 5 solar_mass, delta_t, days_per_year :: Double days_per_year = 365.24 solar_mass = 4 * pi ** 2 delta_t = 0.01 initialize = mapM_ newPlanet planets where dp = days_per_year planets = [0, 0, 0, 0, 0, 0, 1 * solar_mass, 4.84143144246472090e+00, (-1.16032004402742839e+00), (-1.03622044471123109e-01), 1.66007664274403694e-03*dp, 7.69901118419740425e-03*dp, (-6.90460016972063023e-05)*dp, 9.54791938424326609e-04 * solar_mass, 8.34336671824457987e+00, 4.12479856412430479e+00, (-4.03523417114321381e-01), (-2.76742510726862411e-03)*dp, 4.99852801234917238e-03*dp, 2.30417297573763929e-05*dp, 2.85885980666130812e-04 * solar_mass, 1.28943695621391310e+01, (-1.51111514016986312e+01), (-2.23307578892655734e-01), 2.96460137564761618e-03*dp, 2.37847173959480950e-03*dp, (-2.96589568540237556e-05)*dp, 4.36624404335156298e-05 * solar_mass, 1.53796971148509165e+01, (-2.59193146099879641e+01), 1.79258772950371181e-01, 2.68067772490389322e-03*dp, 1.62824170038242295e-03*dp, (-9.51592254519715870e-05)*dp, 5.15138902046611451e-05 * solar_mass ] ------------------------------------------------------------------------ -- Support for 3 dimensional mutable vectors data Vector3 = Vec !Double !Double !Double end :: Ptr Double end = inc planets $ nbodies * 7 next :: Ptr Double -> Ptr Double next p = inc p 7 cursor :: IORef (Ptr Double) cursor = unsafePerformIO $ newIORef planets inc :: Ptr Double -> Int -> Ptr Double inc ptr n = plusPtr ptr (n * 8) newPlanet :: Double -> IO () newPlanet !d = do ptr <- readIORef cursor pokeElemOff ptr 0 d writeIORef cursor (inc ptr 1) pos :: Ptr Double -> Ptr Double pos ptr = ptr vel :: Ptr Double -> Ptr Double vel ptr = inc ptr 3 mass :: Ptr Double -> IO Double mass ptr = peekElemOff ptr 6 ------------------------------------------------------------------------ (Vec x y z) .+. (Vec u v w) = Vec (x+u) (y+v) (z+w) (Vec x y z) .-. (Vec u v w) = Vec (x-u) (y-v) (z-w) k *. (Vec x y z) = Vec (k*x) (k*y) (k*z) -- allocates magnitude2 (Vec x y z) = x*x + y*y + z*z ------------------------------------------------------------------------ getVec !p = liftM3 Vec (peek p) (f 1) (f 2) where f = peekElemOff p setVec p (Vec x y z)= do poke p x pokeElemOff p 1 y pokeElemOff p 2 z infix 4 += infix 4 -= v1 += (Vec u v w) = do x <- peek v1; poke v1 (x+u) y <- peekElemOff v1 1; pokeElemOff v1 1 (y+v) z <- peekElemOff v1 2; pokeElemOff v1 2 (z+w) v1 -= (Vec u v w) = do x <- peek v1; poke v1 (x-u) y <- peekElemOff v1 1; pokeElemOff v1 1 (y-v) z <- peekElemOff v1 2; pokeElemOff v1 2 (z-w)
notes
make, command-line, and program output logs
Tue, 09 Jun 2009 00:53:40 GMT MAKE: mv nbody.ghc-2.ghc nbody.ghc-2.hs /usr/local/src/ghc-6.10.3/bin/ghc --make -O2 -fglasgow-exts -funbox-strict-fields -XBangPatterns -fexcess-precision -funfolding-use-threshold=16 -optc-O3 nbody.ghc-2.hs -o nbody.ghc-2.ghc_run [1 of 1] Compiling Main ( nbody.ghc-2.hs, nbody.ghc-2.o ) Linking nbody.ghc-2.ghc_run ... rm nbody.ghc-2.hs 1.13s to complete and log all make actions COMMAND LINE: ./nbody.ghc-2.ghc_run 50000000 PROGRAM OUTPUT: -0.169075164 -0.169059907