On Mon, 2008-10-06 at 21:06 -0500, Mike Coleman wrote:
> There's a readInt method, which I guess I could use, but it returns a
> Maybe, and I don't see how I can easily strip that off.
You can use Data.Maybe's 'mapMaybe' function
"The mapMaybe function is a version of map which can throw out eleme
Hello wman,
Tuesday, October 7, 2008, 8:44:48 AM, you wrote:
> btw, why is the example #2
> (http://shootout.alioth.debian.org/gp4/benchmark.php?test=sumcol&lang=ghc&id=2)
> (which kicks collective asses of all other participants) not
> considered in the shootout ? Too much optimizations ?
it's
Hello Brandon,
Tuesday, October 7, 2008, 7:59:06 AM, you wrote:
> is there a reason why -O2 shouldn't be made the default (and
> allowing to turn off optimizations by -O0 perhaps) ?
it compiles ~2x slower and firces more recompilation (because it does
inter-module inlining). so it's not perfect
as usual, i forgot to use the magical "reply to all" and under the
impression I'm still talking to the list had bothered dons personally
(heresy/sacrilege/deathwish , i know)
to rectify it a bit at least, i'm posting a summary, in hopes someone find
it useful.
-- this d
666wman:
>ghc -Onot -fstrictness --make Main1.hs && ghc -Onot -fstrictness --make
>Main2.hs && ghc -Onot -fstrictness --make Main3.hs
>
>time Main1 < nums
>real0m39.530s
>user0m0.015s
>sys 0m0.030s
>
>time Main2 < nums
>real0m14.078s
>user0m
ghc -Onot -fstrictness --make Main1.hs && ghc -Onot -fstrictness --make
Main2.hs && ghc -Onot -fstrictness --make Main3.hs
time Main1 < nums
real0m39.530s
user0m0.015s
sys 0m0.030s
time Main2 < nums
real0m14.078s
user0m0.015s
sys 0m0.015s
time Main3.exe < nums
real0m
666wman:
>just for the kicks i tried the new version of bytestring without -O2 and
>the results were even worse:
Note that without -O or -O2 no strictness analysis is performed. So that
tail recursive loop ... won't be. You could try -Onot -fstrictness just
for kicks, to see why strictness
On Mon, Oct 6, 2008 at 10:19 PM, Don Stewart <[EMAIL PROTECTED]> wrote:
> To compile, try something like:
>
>ghc -O2 --make A.hs
That did the trick--thanks.
For input large enough to be a good test, this is I/O-bound on my
laptop (the speed of the compiled and interpreted versions are almost
On 2008 Oct 6, at 23:54, wman wrote:
just for the kicks i tried the new version of bytestring without -O2
and the results were even worse:
Yep, ByteString does a lot of stuff that is really bad when GHC isn't
performing stream fusion --- but when it is, the code compiles down to
tight mach
just for the kicks i tried the new version of bytestring without -O2 and the
results were even worse:
time Main1 < nums
real0m40.092s
user0m0.015s
sys 0m0.015s
time Main3 < nums
real0m41.405s
user0m0.015s
sys 0m0.015s
it got pwned even by this very naive ruby scipt (which
new figures, after updating bytestring (0.9.0.1.1 -> 0.9.1.2) && using -O2
time Main < nums
real0m2.531s
user0m0.015s
sys 0m0.015s
time Main2 < nums
real0m13.999s
user0m0.015s
sys 0m0.015s
time Main3 < nums
real0m2.796s
user0m0.015s
sys 0m0.015s
thats more li
tutufan:
> Thanks for your replies. Hoogle is pretty cool--I didn't know about that.
>
> I ended up with this, which is pretty close to the original (it will
> also bomb if given non-integer input):
>
> import qualified Data.ByteString.Lazy.Char8 as L
> import qualified Data.Maybe as M
>
> main
Hmm. How are you compiling it? Using bytestring 0.9.1.x ?
Should be fast,
http://shootout.alioth.debian.org/gp4/benchmark.php?test=sumcol&lang=all
Assuming you're turning on optimisations ( ghc -O2 )
-- Don
666wman:
>the problem is that using readInt is actually _as slow_, at least usi
the problem is that using readInt is actually _as slow_, at least using my
test script :-((
On Tue, Oct 7, 2008 at 5:12 AM, Don Stewart <[EMAIL PROTECTED]> wrote:
> 666wman:
> >a slight modification to compile it :
> >
> >change:
> >where sumFile = sum . map read . L.words
> >to :
Thanks for your replies. Hoogle is pretty cool--I didn't know about that.
I ended up with this, which is pretty close to the original (it will
also bomb if given non-integer input):
import qualified Data.ByteString.Lazy.Char8 as L
import qualified Data.Maybe as M
main = do
contents <-
666wman:
>a slight modification to compile it :
>
>change:
>where sumFile = sum . map read . L.words
>to :
>where sumFile = sum . map (read . L.unpack) . L.words
>
>but it's actually _slower_ than the non-bytestring version.
Never unpack a bytestring.
import qualifie
a slight modification to compile it :
change:
where sumFile = sum . map read . L.words
to :
where sumFile = sum . map (read . L.unpack) . L.words
but it's actually _slower_ than the non-bytestring version.
i did a little test, three versions of the same script and manufactured
meself a ~50 MB f
Am Dienstag, 7. Oktober 2008 04:21 schrieb Jason Dagit:
> On Mon, Oct 6, 2008 at 7:06 PM, Mike Coleman <[EMAIL PROTECTED]> wrote:
> > Hi,
> >
> > I could use a little help. I was looking through the Real World
> > Haskell book and came across a trivial program for summing numbers in
> > a file. T
dagit:
>As the top search result.
>
>This means that you can convert any list of maybes into a list of what you
>want. It just tosses out the Nothings.
>
> 2. Why doesn't ByteString implement 'read'? Is it just that this
> function (like 'input' in Python) isn't really ve
On Mon, Oct 6, 2008 at 7:06 PM, Mike Coleman <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I could use a little help. I was looking through the Real World
> Haskell book and came across a trivial program for summing numbers in
> a file. They mentioned that that implementation was very slow, as
> it's bas
Hi,
I could use a little help. I was looking through the Real World
Haskell book and came across a trivial program for summing numbers in
a file. They mentioned that that implementation was very slow, as
it's based on String's, so I thought I'd try my hand at converting it
to use lazy ByteString
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