Re: precision octave vs matlab

[Søren Hauberg]

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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