Shootout/Random

A Shootout Entry for the random benchmark.

Current entry

Using `rem` (as the Clean entry does) halves running time on Linux/p4 (!) and about 10% faster on OpenBSD.

I see the same effect, or greater (!), on my powerbook with those compile options. Are you gong to submit this? -- ChrisKuklewicz

This has been submitted, however only a minor speedup occured on the gp4 test machine. Sigh. -- Dons

-- $Id: random-ghc.code,v 1.28 2006/01/08 23:33:35 igouy-guest Exp $
-- http://shootout.alioth.debian.org
--
-- Original by Simon Marlow
-- Heavily modified by Einar Karttunen, further by Don Stewart
--
--  ghc -o c C.hs -O3 -optc-O3 -fexcess-precision -fglasgow-exts 
--

import System; import Numeric

main = putStrLn . (\n -> showFFloat (Just 9) (randl (n-1) 42) []) . read . head =<< getArgs

randl (n::Int) (seed::Int) = if n == 0 then nr else randl (n-1) ns :: Double
  where (ns,nr)    = ((seed * ia + ic) `rem` im, 100 * (fromIntegral ns) / fromIntegral im)
        (im,ia,ic) = (139968,3877,29573)

Current entry

Shortest entry in any language

{-# OPTIONS -fglasgow-exts -O2 -optc-O3 #-}
-- $Id: random-ghc.code,v 1.28 2006/01/08 23:33:35 igouy-guest Exp $
-- http://shootout.alioth.debian.org
--
-- Original by Simon Marlow
-- Heavily modified by Einar Karttunen and Don Stewart

import System; import Numeric

main = putStrLn . (\n -> showFFloat (Just 9) (randl (n-1) 42) []) . read . head =<< getArgs

randl (n::Int) (seed::Int) = if n == 0 then nr else randl (n-1) ns :: Double
  where (ns,nr)    = ((seed * ia + ic) `mod` im, (fromIntegral ns) * (100 / fromIntegral im))
        (im,ia,ic) = (139968,3877,29573)

Older entry

{-# OPTIONS -O3 #-}
-- $Id: random-ghc.code,v 1.28 2006/01/08 23:33:35 igouy-guest Exp $
-- http://shootout.alioth.debian.org
--
-- Original by Simon Marlow
-- Heavily modified by Einar Karttunen

import System(getArgs)
import Numeric(showFFloat)

main = do ~[n] <- getArgs
          putStrLn (showFFloat (Just 9) (randl 100 ((read n)-1) 42) "")

randl :: Double -> Int -> Int -> Double
randl max n seed = newseed `seq` newrand `seq`
  if n == 0 then newrand else randl max (n-1) newseed
    where newseed = (seed * ia + ic) `mod` im
          newrand = (fromIntegral newseed) * (max / fromIntegral im)
          im = 139968
          ia = 3877
          ic = 29573