Shootout/Mandelbrot
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A Shootout Entry for the mandelbrot benchmark.
Contents |
1 Entry
-- The Great Computer Language Shootout -- http://shootout.alioth.debian.org/ -- Based on version by Don Stewart -- Contributed by Trevor McCort import System import Data.Bits import Data.Word import GHC.Base main = do w <- getArgs >>= readIO . head let ch = chr.fromIntegral sh = show $ fromEnum w (bw::Int) = ceiling $ w / 8 gb x ci b n | x == w = ch $ b `shiftL` n | n == 0 = ch b | otherwise = gb (x+1) ci (b+b+(lp 0.0 0.0 50 cr ci)) (n-1) where cr = x * 2.0 / w - 1.5 ms bx x y ci | y == w = [] | bx == bw = gb x ci 0 8 : ms 1 0 (y+1) ((y+1) * 2.0 / w - 1.0) | otherwise = gb x ci 0 8 : ms (bx+1) (x+8) y ci putStrLn ("P4\n"++sh++" "++sh) mapM_ putChar $ ms 1 0 0 (-1.0) lp r i k cr ci | r2 + i2 > (4.0 :: Double) = 0 :: Word32 | k == (0 :: Word32) = 1 | otherwise = lp (r2-i2+cr) ((r+r)*i+ci) (k-1) cr ci where r2 = r*r ; i2 = i*i
2 Current Entry
Shortest entry in any language.
As with all programs using doubles, compile with -fexcess-precision for big speedups.
-- The Great Computer Language Shootout -- http://shootout.alioth.debian.org/ -- Based on the SML version, written by Matthias Blume. -- Implemented in Haskell by Don Stewart -- import System; import Data.Bits; import Data.Word; import GHC.Base main = do (w::Word32) <- getArgs >>= readIO . head putStrLn ("P4\n"++show w++" "++show w) >> yl 0 w w yl y h w = if y < h then xl 0 y 0 8 h w else return () xl x y b n h w | x == w = putChar (unsafeChr $ b `shiftL` n) >> yl (y+1) h w | otherwise = do (b',n') <- if n == 0 then putChar (chr b) >> return (0,8) else return (b,n) xl (x+1) y (b'+b'+ fromEnum (p x y w h)) (n'-1) h w p (x::Word32) y w h = lp 0.0 0.0 50 (f x * 2.0 / f w - 1.5) (f y * 2.0 / f h - 1.0) where f = fromIntegral lp r i k cr ci | r2 + i2 > (4.0 :: Double) = 0 :: Word32 | k == (0 :: Word32) = 1 | otherwise = lp (r2-i2+cr) ((r+r)*i+ci) (k-1) cr ci where r2 = r*r ; i2 = i*i
3 Current Entry
The old entry below is 1.2x slower than this version.
This is a translation of the fast SML version. Additionally, we get some good gains by using Word32. (I wonder if this will apply elsewhere?) The -optc-O2 helps as well (another thing to keep in mind for other entries).
{-# OPTIONS -O2 -optc-O2 #-} -- -- Based on the SML version, written by Matthias Blume. -- Implemented in Haskell by Don Stewart -- import System import Data.Bits import Data.Word import GHC.Base main = do w <- getArgs >>= return . read . head putStrLn $ "P4\n" ++ show w ++ " " ++ show w yl 0 w w yl y h w = if y < h then xl 0 y 0 8 h w else return () xl x y b n h w | x == w = putChar (unsafeChr $ b `shiftL` n) >> yl (y+1) h w | otherwise = do (b',n') <- if n == 0 then putChar (chr b) >> return (0,8) else return (b,n) xl (x+1) y (b'+b'+ fromEnum (p x y w h)) (n'-1) h w p :: Word32 -> Word32 -> Word32 -> Word32 -> Word32 p x y w h = lp 0.0 0.0 50 (f x * 2.0 / f w - 1.5) (f y * 2.0 / f h - 1.0) where f = fromIntegral lp r i k cr ci | r2 + i2 > (4.0 :: Double) = 0 :: Word32 | k == (0 :: Word32) = 1 | otherwise = lp (r2-i2+cr) ((r+r)*i+ci) (k-1) cr ci where (r2,i2) = (r*r, i*i)
4 Original entry
Quite good, though all the lists seem a bit worrying. Also, is putStr legal in this entry?
-- contributed by Greg Buchholz -- modified by Alson Kemp -- improvements by Jean-Philippe Bernardy -- compile: ghc -O2 -o mandelbrot mandelbrot.hs -- run: mandelbrot 600 >mandel.pbm import Complex import System(getArgs) import Char(chr) import System.IO limit = 4.0::Double iter = 50::Int main = do [arg] <- getArgs let width = read arg --AK:optional;prevent newline mangle on PC hSetBinaryMode stdout True putStr $ "P4\n" ++ show width ++ " " ++ show width ++ "\n" mapM_ putStr $ map (makePBM 0 0) $ fractal (points width width) points :: Int -> Int -> [[Complex Double]] points width height = [[(2.0*x/w - 1.5) :+ (2.0*y/h - 1) | x<-[0..w-1]] | y<-[0..h-1]] where w = fromIntegral width h = fromIntegral height fractal :: [[Complex Double]] -> [[Int]] fractal = map $ map $ fractal' (0.0 :+ 0.0) iter -- magnitude is sloooooowwwwww, so hand code abs^2 fractal' :: Complex Double -> Int -> Complex Double -> Int fractal' z i c | (realPart z')*(realPart z') + (imagPart z')*(imagPart z') > limit = 0 | (i == 1) = 1 | otherwise = fractal' z' (i-1) c where z' = z*z+c makePBM :: Int -> Int -> [Int] -> [Char] makePBM i acc [] = chr (acc * 2^(8-i)) : [] makePBM i acc (x:xs) | i==8 = chr acc : makePBM 0 0 (x:xs) | otherwise = makePBM (i+1) (acc*2 + x) xs
