Also, prefer quotRem over divMod as the former is faster. See here: http://stackoverflow.com/questions/339719/when-is-the-difference-between-quo... On Wed, Feb 19, 2014 at 10:19 AM, Gregory Collins wrote:

On Wed, Feb 19, 2014 at 9:36 AM, Charles-Pierre Astolfi wrote:

...

So there's a difference, but I'm not sure if it's related to my algorithm or related to IO/RTS.

Text.Printf is slower than the C version (and uses String). Use Data.ByteString.putStr instead.

-- Gregory Collins

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Hi Charles, I had in mind comparing with similar tool the C version, but it looks like I was a bit naive at thinking that same tooling exist for C (after googling a bit it sounds there is no lib like that). OTOH, Bryan O'Sullivan mention in his original blog past about criterion that it could be potentially used to benchmark C code as well. The cost of putting that in place might outperform the benefit though. Cheers Alois On 19 February 2014 18:49, Charles-Pierre Astolfi wrote:

Switching to quotRem gave no measurable improvements. After switching to ByteString, the code now runs in 9 seconds, which outperforms my C version. But honestly, I have no idea why.

New code: http://lpaste.net/100136

$ ghc --make -O3 303only012.hs && time ./303only012 50000000 > /dev/null ./303only012 50000000 > /dev/null 9.72s user 0.21s system 90% cpu 10.961 total

@Alois, I'm not sure how criterion can help compare my code with the C version, since in the C version I cannot measure the exec time of only012 only. What did you have in mind?

Thanks everyone!

-- Cp

On Wed, Feb 19, 2014 at 7:24 PM, Levent Erkok wrote:

...

Also, prefer quotRem over divMod as the former is faster. See here: http://stackoverflow.com/questions/339719/when-is-the-difference-between-quo...

On Wed, Feb 19, 2014 at 10:19 AM, Gregory Collins < greg@gregorycollins.net> wrote:

...

On Wed, Feb 19, 2014 at 9:36 AM, Charles-Pierre Astolfi wrote:

...

So there's a difference, but I'm not sure if it's related to my algorithm or related to IO/RTS.

Text.Printf is slower than the C version (and uses String). Use Data.ByteString.putStr instead.

-- Gregory Collins

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-- *Alois Cochard* http://aloiscochard.blogspot.com http://twitter.com/aloiscochard http://github.com/aloiscochard