How much output does this generate? Does it matter if you send the
output to /dev/null? This looks as if the bottleneck might well be in
I/O operations, not in the code itself. To find this out, you could
rewrite the code in C and see if that makes a difference?
Thomas
On Sun, Jun 14, 2009 at 20:44, brian
Haskell Gurus,
I have tried to use profiling to tell me what's going on here, but it hasn't helped much, probably because I'm not interpreting the results correctly.
Empirically I have determined that the show's are pretty slow, so an alternative to them would be helpful. I replaced the show's with "", and compiled with -O2 and not much improvement.
I need to write _a lot_ of code in this style. A few words about how best to do this would be helpful. Laziness, infinite lists, uvector ??
Help...
Thanks,
Brian
import Complex import System.IO
genData :: Double -> Int -> (Double -> Complex Double) -> ([Double], [Complex Double]) genData tstop n f = let deltat = tstop / (fromIntegral n) t = [ fromIntegral(i) * deltat | i <- [0..n-1]] in (t, map f t)
main = do let (t, y) = genData 100.0E-6 (2 ^ 15) (\x -> x :+ 0.0) h <- openFile "data.txt" WriteMode mapM_ (\(x, y) -> do hPutStr h (show t) hPutStr h " " hPutStrLn h (show (realPart y))) (zip t y) hClose h _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe