bugGNU Octave - Bugs: bug #43699, [optim] Error in curvefit_stat...

 
 

bug #43699: [optim] Error in curvefit_stat when requesting covp with multiple correlated parameters

Submitter:  Markus Appel <mappel>
Submitted:  Tue 25 Nov 2014 04:14:29 PM UTC
   
 
Category:  Octave Package Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Segfault, Bus Error, etc.
Status:  Fixed Assigned to:  None
Originator Name:  Open/Closed:  * Closed
Release:  * 3.8.0 Operating System:  * GNU/Linux
Fixed Release:  None Planned Release:  None
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Fri 28 Nov 2014 01:47:55 PM UTC, comment #2: 

Sorry, I've forgotten to commit the last change before pushing. It is now in a changeset with some additional changes addressing the remaining issues I mentioned.

Olaf Till <i7tiol>
Group Member
Wed 26 Nov 2014 02:29:15 PM UTC, comment #1: 

Thanks for the report. The triggering error was just usage of a vector in the wrong orientation, but there turned out to be an additional problem with usage of error bounds for basis vectors of more than one-dimensional null spaces. A fix for the bug is now pushed; tell me if you need a summarizing patch for the time before a new package release.

Though this bug should be fixed, there seem to be still some issues with the procedure computing covd and corp, but I'll need a bit time for this.

Olaf Till <i7tiol>
Group Member
Tue 25 Nov 2014 04:14:29 PM UTC, original submission:  

When running the attached minimal test script, I get the following error from the curvefit_stat call:

octave:1> curvefittest
error: __null_optim__: mx_el_le: nonconformant arguments (op1 is 4x2, op2 is 8x1)
error: called from:
error:   /home/mappel/octave/optim-1.4.0/private/__null_optim__.m at line 104, column 14
error: evaluating argument list element number 1
error:   /home/mappel/octave/optim-1.4.0/private/__covp_corp_wls__.m at line 64, column 5
error:   /home/mappel/octave/optim-1.4.0/private/__residmin_stat__.m at line 551, column 10
error:   /home/mappel/octave/optim-1.4.0/curvefit_stat.m at line 56, column 7
error:   /home/mappel/test/curvefittest.m at line 38, column 6

with optim 1.4.0 in octave 3.8.0 on Ubuntu 12.04.
In the script, I have added dummy parameters on which the model function does not depend to provoke the error. In reality I encountered this error when multiple parameters of a model function became fully correlated.

From playing around it seems that _null_optim_ cannot handle an input matrix with more than one singular value being zero (within tol). Commenting out line 20: "PIN.dummy2 = 1;" in the demonstration script makes it work and results in the expected correlation matrix INFO.covp with one row/column being NA.

Markus Appel <mappel>

 

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Attached Files
file #32542:  curvefittest.m added by mappel (742B - text/x-objcsrc)

 

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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2014-11-28 carandraug StatusNone Fixed
        Open/ClosedOpen Closed
    2014-11-25 mappel Attached File- Added curvefittest.m, #32542
        Carbon-Copy- Added -email is unavailable-

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