[bug #7845] full_analysis.py problem with the chi2 from the previous run (precision too high ?) -- November 24, 2006 - 17:22

URL:
  <http://gna.org/bugs/?7845>

                 Summary: full_analysis.py problem with the chi2 from the
previous run (precision too high ?)
                 Project: relax
            Submitted by: semor
            Submitted on: Friday 11/24/2006 at 16:22
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: Repository: 1.2 line
        Operating System: GNU/Linux

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Details:

> From the 1.2 line at revision 2883...

The new full_analysis.py script has the ability to tell if convergence has
been reached by looking at the chi2, model-free models, diffusion tensor
parameters and model-free parameters from the previous round of optimization.
This should prevent running the final global optimization before every
diffusion tensor convergence.

However, the chi2 test doesn't work.

After a lot of optimization rounds with the old script, I tried the new one.
For example, it was the 12th round for the prolate diffusion tensor. The
first time I used the new script, it told me the previous chi2 was
7086.7226167700001 and the new one was 7086.7226167680947. I then continued
and got the same exact chi2 for the previous and new round... I did it
another time and got the exact same thing again.

So, the 'previous' chi2 is always 7086.7226167700001 ans the 'present' chi2
is always 7086.7226167680947 for this particular diffusion tensor using my
data.

I get the same behaviour for every diffusion tensor, so this is global
error.

Also, the chi2 difference is extremely small, not even visible when taking a
look at the results.bz2 file, since the round up values are the same.

The other tests (model-free models, diffusion tensor parameters and
model-free parameters) seem to work.

Maybe this is related to the calculation precision...

Thanks for help !

Séb





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