bugGNU Octave - Bugs: bug #36015, unexpected sqp error


bug #36015: unexpected sqp error

Submitted by:  John W. Eaton <jwe>
Submitted on:  Tue Mar 27 15:28:12 2012  
Category: Octave FunctionSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Incorrect Result
Status: FixedAssigned to: Lachlan Andrew <lachlan>
Originator Name: Open/Closed: Closed
Release: devOperating System: GNU/Linux

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Mon Aug 8 22:13:47 2016, comment #3:

@Lachlan: I pushed your patch here http://hg.savannah.gnu.org/hgweb/octave/rev/20e0c0b8820c. This must have been one of the first patches you wrote since I corrected syntax things like using '%' as the comment character. Thanks for all the help with these old reports.

Rik <rik5>
Project Administrator
Sat Feb 27 05:23:14 2016, comment #2:

There seem to be two problems here.

The clearest problem is that qp.m uses the wrong size matrices for C and the lower bound. From the comments in the code, Ain must have n columns (as it is multiplied by x), but a value of n-n_eq was being used.

I don't really understand the algorithm, so I can't confirm that that is the only bug, but since it is just changing the size of a vector of zeros or infinities, I assume that is the right fix.

Once that is fixed, qp returns an infeasible solution, and returns lambda=[]. This causes an error in sqp, so this patch sets lambda to its previous value if qp returns an infeasible solution. A warning is shown anyway, so the user knows not to trust the results; this just prevents an inexplicable error.

It would be great if someone who understands this code could check the changes.

(file #36487)

Lachlan Andrew <lachlan>
Project MemberIn charge of this item.
Fri Nov 8 21:38:30 2013, comment #1:

The problem is still here in Octave 3.7.7+ (3851e5fde76d)

Julien Bect <jbect>
Tue Mar 27 15:28:12 2012, original submission:

The following code

results in the error:

I found this bug report in an old set of messages that were never correctly posted to the -unavailable- mailing list.
Sorry for not posting it before now.

John W. Eaton <jwe>
Project Administrator


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Attach File(s):

Attached Files
file #36487:  bug_36015_sqp.cset added by lachlan (3kB - text/x-diff)


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -unavailable- added by rik5 (Posted a comment)
  • -unavailable- added by lachlan (Updated the item)
  • -unavailable- added by jbect (Posted a comment)
  • -unavailable- added by mtmiller (Updated the item)
  • -unavailable- added by jwe (Submitted the item)
  • -unavailable- added by jwe

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    Follow 9 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Mon Aug 8 22:13:47 2016rik5StatusPatch Submitted=>Fixed
    Sat Feb 27 05:23:14 2016lachlanAttached File-=>Added bug_36015_sqp.cset, #36487
      StatusConfirmed=>Patch Submitted
      Assigned toNone=>lachlan
    Mon Oct 28 02:50:04 2013mtmillerCategoryLibraries=>Octave Function
    Tue Mar 27 15:28:12 2012jweCarbon-Copy-=>Added -unavailable-

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