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true parallelism / threads
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Date: 2009-02-20 (17:01)
From: Will M. Farr <farr@m...>
Subject: Re: [Caml-list] true parallelism / threads

I've had some luck using OCaml with MPI (using the OCamlMPI library at
http://caml.inria.fr/cgi-bin/hump.en.cgi?contrib=401 ).  That may not
satisfy your needs as far as multi-core goes, but perhaps it will.  I
can't speak to the speed of the interface (my operations were
compute-bound on the individual processors, not communication bound,
so any OCaml overhead on the MPI communication was lost in the noise),
but it was definitely easy to use.  At the extreme easy-to-use end,
you can simply send arbitrary OCaml values over the MPI channels; for
more performance, you can use the functions specific to common types
(float arrays, int arrays, etc) to speed up the operations.

As far as single-core OCaml speed goes, I find that it is always
within a factor of 2 of C for straight-line loops (i.e. matrix-vector
multiply, etc), and usually *much* faster whenever more complicated
data structures are involved (maps, binary trees, etc), unless you
really sweat blood with the C implementation.

Hope this helps!


2009/2/20 Atmam Ta <atmamta2@gmail.com>:
> Hi,
> I am trying to evaluate ocaml for a project involving large scale numerical
> calculations. We would need parallel processing, i.e. a library that
> distributes jobs accross multiple processors within a machine and accross
> multiple PCs.
> Speed and easy programability are important. I have tried to search this
> issue first, but the postings I found were usually negative and 4-5 years
> old. On the other hand, I see a number of libraries in the Hump that by now
> might be taking care of these things.
> My question is: is ocaml good for parallel processing / hreaded computation,
> are there (mature) libraries or tools that let developers make use of
> multicore and multimachine environments?
> cheers,
> Atmam
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