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

[Markus Appel]

URL:
  <http://savannah.gnu.org/bugs/?43699>

                 Summary: [optim] Error in curvefit_stat when requesting covp
with multiple correlated parameters
                 Project: GNU Octave
            Submitted by: mappel
            Submitted on: Tue 25 Nov 2014 04:14:29 PM GMT
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Crash
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.8.0
        Operating System: GNU/Linux

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Details:

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.



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File Attachments:


-------------------------------------------------------
Date: Tue 25 Nov 2014 04:14:29 PM GMT  Name: curvefittest.m  Size: 742B   By:
mappel

<http://savannah.gnu.org/bugs/download.php?file_id=32542>

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