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precision octave vs matlab
From: |
michaelschmid1 |
Subject: |
precision octave vs matlab |
Date: |
Thu, 1 Jun 2006 07:03:50 +0200 |
I don't think it's a octave bug. If it's a bug, I think I'm the culprit :-(
The complete algorithm need several hundred lines of code... so I don't think
I will put this here...
I will do some more search and if I will find a position where I don't know
why a difference occurs... I will ask again...
but then with code ...
thanks
michel
On 29-May-2006, address@hidden wrote:
| 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..
Given the information you have provided (just the outputs and no code)
how can anyone tell?
If you think you have found a bug in Octave, then please submit a
complete bug report to the address@hidden list. But please read
www.octave.org/bugs.html first to learn how to submit a useful bug
report that provides enough information to allow someone to actually
fix the problem.
Thanks,
jwe
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