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[Caml-list] Q: Efficient operations on complex numbers
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Date: -- (:)
From: Jan Kybic <kybic@f...>
Subject: Re: [Caml-list] Q: Efficient operations on complex numbers
Xavier Leroy:
> Yes, it does, if the .cmx files for the other compilation units are
> available.  So, I'm a bit surprised about what Jan Kybic observed.
> What I would have expected is that referring to the Complex module or
> copying it inside the source file shouldn't change the generated
> code, at least if you stay at the default inlining level.

Thank you for your reply. Yes, you are right, if I inline at
sufficiently high level (say 'ocamplopt -inline 10), then using the
Complex module is as fast as copying the code. 

As for the slowdown, it apparently depends on the compiler and/or
processor. On my system:

    Intel(R) Pentium(R) M processor 1400MHz
    Mandrake Linux release 9.1 (Bamboo) for i586
    gcc version 3.2.2 (Mandrake Linux 9.1 3.2.2-3mdk)
    The Objective Caml native-code compiler, version 3.07

I find that Ocaml program takes about 170~200% of the time of the C++
version, while on Christophe TROESTLER's machine (Intel(R) Pentium(R)
4 CPU 2.40GHz)), who kindly repeated my experiments, it was just
140%. So this is really a complex issue with many variables.

If I gain more insight into it, I will keep you posted.

Jan

-- 
-------------------------------------------------------------------------
Jan Kybic <kybic@ieee.org>                  tel. +420 2 2435 7264
       or <kybic@fel.cvut.cz>,     http://cmp.felk.cvut.cz/~kybic

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