Here is haskell version that is faster than python, almost as fast as c++.You
need to install bytestring-lexing package for readDouble.
bmaxa@maxa:~/haskell$ time ./printMatrixDecay - < output.txtread 16384 matrix
elements (128x128 = 16384)[0.00e0, 1.00e-8) = 0 (0.00%) 0[1.00e-8, 1.00e-7) = 0
(0.00%) 0[1.00e-7, 1.00e-6) = 0 (0.00%) 0[1.00e-6, 1.00e-5) = 0 (0.00%)
0[1.00e-5, 1.00e-4) = 1 (0.01%) 1[1.00e-4, 1.00e-3) = 17 (0.10%) 18[1.00e-3,
1.00e-2) = 155 (0.95%) 173[1.00e-2, 1.00e-1) = 1434 (8.75%) 1607[1.00e-1,
1.00e0) = 14777 (90.19%) 16384[1.00e0, 2.00e0) = 0 (0.00%) 16384
real 0m0.031suser 0m0.028ssys 0m0.000sbmaxa@maxa:~/haskell$ time
./printMatrixDecay.py - < output.txt(-) read 16384 matrix elements (128x128 =
16384)[0.00e+00, 1.00e-08) = 0 (0.00%) 0[1.00e-08, 1.00e-07) = 0 (0.00%)
0[1.00e-07, 1.00e-06) = 0 (0.00%) 0[1.00e-06, 1.00e-05) = 0 (0.00%) 0[1.00e-05,
1.00e-04) = 1 (0.00%) 1[1.00e-04, 1.00e-03) = 17 (0.00%) 18[1.00e-03, 1.00e-02)
= 155 (0.00%) 173[1.00e-02, 1.00e-01) = 1434 (0.00%) 1607[1.00e-01, 1.00e+00) =
14777 (0.00%) 16384[1.00e+00, 2.00e+00) = 0 (0.00%) 16384
real 0m0.081suser 0m0.080ssys 0m0.000s
Program follows...
import System.Environmentimport Text.Printfimport Text.Regex.PCREimport
Data.Maybeimport Data.Array.IOimport Data.Array.Unboxedimport qualified
Data.ByteString.Char8 as Bimport Data.ByteString.Lex.Double (readDouble)
strataBounds :: UArray Int DoublestrataBounds = listArray (0,10) [ 0.0, 1.0e-8,
1.0e-7, 1.0e-6, 1.0e-5, 1.0e-4, 1.0e-3, 1.0e-2, 1.0e-1, 1.0, 2.0 ]
newStrataCounts :: IO(IOUArray Int Int)newStrataCounts = newArray (bounds
strataBounds) 0
main = do l <- B.getContents let a = B.lines l strataCounts <-
newStrataCounts n <- calculate strataCounts a 0 let
printStrataCounts :: IO () printStrataCounts = do let s =
round $ sqrt (fromIntegral n::Double) :: Int printf "read %d matrix
elements (%dx%d = %d)\n" n s s n printStrataCounts' 0 0
printStrataCounts' :: Int -> Int -> IO () printStrataCounts' i total
| i < (snd $ bounds strataBounds) = do count <-
readArray strataCounts i let p :: Double
p = (100.0*(fromIntegral count) :: Double)/(fromIntegral n ::
Double) printf "[%1.2e, %1.2e) = %i (%1.2f%%) %i\n"
(strataBounds ! i) (strataBounds ! (i+1))
count p (total + count)
printStrataCounts' (i+1) (total+count) | otherwise = return ()
printStrataCounts
calculate :: IOUArray Int Int -> [B.ByteString] -> Int -> IO Intcalculate _ []
n = return ncalculate counts (l:ls) n = do let a = case
getAllTextSubmatches $ l =~ B.pack "matrix.*= ([0-9eE.+-]+)$" :: [B.ByteString]
of [_,v] -> Just (readDouble v) :: Maybe (Maybe
(Double,B.ByteString)) _ -> Nothing b =
(fst.fromJust.fromJust) a loop :: Int -> IO() loop i |
i < (snd $ bounds strataBounds) = if (b >= (strataBounds ! i))
&& (b < (strataBounds ! (i+1))) then do c <-
readArray counts i writeArray counts i (c+1)
else loop (i+1) | otherwise = return () if
isNothing a then calculate counts ls n else do
loop 0 calculate counts ls (n+1)
From: nicolasb...@gmail.com
Date: Fri, 8 Feb 2013 12:26:09 -0700
To: haskell-cafe@haskell.org
Subject: [Haskell-cafe] performance question
Hi list,
I wrote a script that reads matrix elements from standard input, parses the
input using a regular expression, and then bins the matrix elements by
magnitude. I wrote the same script in python (just to be sure :) ) and find
that the python version vastly outperforms the Haskell script.
To be concrete:
$ time ./createMatrixDump.py -N 128 | ./printMatrixDecayreal 0m2.655s
user 0m2.677ssys 0m0.095s
$ time ./createMatrixDump.py -N 128 | ./printMatrixDecay.py -
real 0m0.445suser 0m0.615ssys 0m0.032s
The Haskell script was compiled with "ghc --make printMatrixDecay.hs".
Could you have a look at the script and give me some pointers as to where I
could improve it, both in terms of performance and also generally, as I am very
new to Haskell.
Thanks already,
nick
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