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Re: benchmarking - evidence that there's no problem
From: |
David Bateman |
Subject: |
Re: benchmarking - evidence that there's no problem |
Date: |
Tue, 16 Nov 2004 09:57:11 +0100 |
User-agent: |
Mutt/1.4.1i |
According to address@hidden <address@hidden> (on 11/15/04):
> On Mon, Nov 15, 2004 at 02:56:13PM +0000, Michael Creel wrote:
> > Here are some benchmark results using my USOBS.m script, which is attached.
> > This is certainly not conclusive, but it seems that the problem I had last
> > week may have been due to something other than Octave.
> > Michael
>
> You don't have difference but I do (only in your matrix create)
>
> 2.1.50 matrix create 5.702 100.000 0.057
> 2.1.57 matrix create 5.620 100.000 0.056
> 2.1.61 matrix create 8.653 100.000 0.087
>
> I don't know why rand in my 2.1.61 is 1.5x slower (all version use
> some octave-forge, 2.1.61 has recent (about 7 days) from cvs)
Check the 32/53 bit issues in the octave-forge rand functions. You can
either use the 53-bit versions and get better coverage of all possible
random values, or the 32-bit versions and have some double floating
point values that can not be obtained... The cost is speed. If you
don't care that all floating point values between 0 and 1 can be obtained
by rand use the 32-bit versions and get back the 1.5 factor you observed.
> But my real (deterministic) application is going to infinity :(
>
> 2.1.50 68.4 seconds
> 2.1.57 179.37
> 2.1.61 261.90
>
> My application is (badly) complicated - above 180 m-files.
> Today I will finish my code instrumentation to find drawbacks.
Can you give a simple test case. My experience is exactly the reverse,
and the newer versions are faster.. A slow-up like this is a clear
regression.
> Another issue with my code is that results from 2.1.50 are different to
> 2.1.57/2.1.61 (some rounding problem???).
Again a simple example would help in deciding if this is an issue...
Regards
David
--
David Bateman address@hidden
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Parc Les Algorithmes, Commune de St Aubin +33 1 69 35 77 01 (Fax)
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