Hi all haskellers
I every now and then get the feeling that doing my job code in Haskell would be
a good idea.
I have tried a couple of times, but each time I seem to run into performance
problems - I do lots of heavy computing.
The problem seems to be connected to lazy loading, which makes my programs so
slow that I really can not show them to anyone. I have tried all tricks in the
books, like !, seq, non-lazy datatypes...
I was poking around to see if this had changed, then I ran into this forum
post: http://stackoverflow.com/questions/9409634/is-indexing-of-data-vector-unboxed-mutable-mvector-really-this-slow
The last solution was a haskell program which was in the 3x range to C, which I
think is ok. This was in the days of ghc 7.0
I then tried compile the programs myself (ghc 7.4.1), but found that now the C
program now was more that 100x faster. The ghc code was compiled with both O2
and O3, giving only small differences on my 64-bit Linux box.
So it seems something has changed - and even small examples are still not safe
when it comes to the lazy-monster. It reminds me of some code I read a couple
of years ago where one of the Simons actually fired off a new thread, to make
sure a variable was realized.
A sad thing, since I am More that willing to go for Haskell if proves to be
usable. If anyone can see what is wrong with the code (there are two haskell
versions on the page, I have tried the last and fastest one) it would also be
interesting.
What is your experience, dear haskellers? To me it seems this beautiful
language is useless without a better lazy/eager-analyzer.
Cheers,
Felix
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