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Re: precision octave vs matlab
From: |
Søren Hauberg |
Subject: |
Re: precision octave vs matlab |
Date: |
Mon, 29 May 2006 16:41:32 +0200 |
Hi,
I can't help you with your problem, but I do have two comments:
1) Does it matter? It seems to me that the results are so similar, that
the differences probably don't matter, but I could be mistaken.
2) If you just want some neural networks, you could consider looking at
FANN (http://fann.sf.net). If FANN does what you want, you can use the
Octave binding that I created a while back
(http://hauberg.org/octave-fann).
Sorry, I couldn't be of more assistance,
Søren
man, 29 05 2006 kl. 13:27 +0200, skrev address@hidden:
> Hi all
>
> First thanks for all the answers about my "global" problem... it works now...
>
> but now the next problem..
>
> I have programmed some parts of a neural network toolbox for Octave, like
> the one of matlab. Some commands are working like "newff, train, sim" and
> so on..
> For the first training algorithm I decided to realize Levenberg-Marquardt.
> Now if I make a comparison between the results of matlab and octave, there
> are some small differences...
> I searched for calculating errors but can't find anything. As far as I know,
> both are using double-precision ... so where does this difference come from?
> Is it really a calculating error or only a "rounding error"?
>
> Octave output:
> ================
> simOut =
>
> Columns 1 through 8:
>
> 1.67883 2.05781 1.21596 2.82417 2.06661 2.00662 2.99825 1.65494
>
> Columns 9 through 16:
>
> 1.65087 1.90819 1.90195 1.70142 2.61220 1.99405 0.99050 1.91911
>
> Columns 17 through 24:
>
> 1.94686 0.93073 1.87499 1.75138 1.71708 2.21930 0.94781 2.02244
>
> Columns 25 through 30:
>
> 2.01943 1.10781 2.02009 1.85863 2.71098 1.30415
>
> matlab output:
> ==============
>
> simOut =
>
> Columns 1 through 17
>
> 1.6767 1.9494 1.1277 2.7196 2.0406 1.9435 2.8583
> 1.6444 1.6437 1.8839 1.7769 1.6008 2.7412 1.9360 1.0998
> 1.8426 1.8144
>
> Columns 18 through 30
>
> 1.0464 1.8657 1.7506 1.6612 2.1693 1.0655 1.8792
> 2.0094 1.0119 1.9947 1.8084 2.5923 1.2365
>
> Of course both programmes have the same initial conditions...
>
> I hope someone have similar experience with this kind of "trouble"
> and that this person can tell me that I didn't make a calculation error..
>
> Thanks
> Michel
>
>
>
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