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From: "Andreas Sprenger" <sprenger_a@yahoo.de>
Newsgroups: comp.soft-sys.matlab
Subject: Re: conv2 in R2008b very slow
Date: Fri, 26 Dec 2008 16:16:44 +0000 (UTC)
Organization: Universit&#228;t L&#252;beck
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"Matt" <mjacobson.removethis@xorantech.com> wrote in message <gj2o8i$pul$1@fred.mathworks.com>...
> > Andreas:
> > Interesting question.  here are my times:
> > % in R2008b: 21.170 seconds.
> > % in R2008a:   0.018 seconds.
> 
> Did you check quantitative agreement between the results of each?
> I just can't believe it's possible to do a convolution that size in 0.018 sec.
> 
> But if so, what kind of machine are you using?

Concerning my computer: Core2Duo E6600 (2x2.4 GHz), 2GB RAM, NVIDIA Geforce 7600 GS and Quadro NVS 290, WinXP Prof. 

I did one more test. On my computer I have three versions currently installed and got the following calculation times:

Matlab 7.0.0.19920: 0.016000 s
Matlab 7.6.0.324: 0.019018 s
Matlab 7.7.0.471: 17.730552 s

I subtracted those three results one another: no differences, all are the same (sum(sum(abs(A - B))). I'm really interested in what's the reason for this big difference in calculation speed.

In the lab we have some older PCs with single user licenses running ML 6.0 and 6.5. I could check the calculation times on these machines in a few days...


Andreas