bugGNU Octave - Bugs: bug #52402, Incorrect size of the solution of...

 
 

bug #52402: Incorrect size of the solution of a singular system

Submitter:  Marco Caliari <caliari>
Submitted:  Tue 14 Nov 2017 08:42:37 AM UTC
   
 
Category:  Octave Function Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Fixed Assigned to:  None
Originator Name:  Open/Closed:  * Closed
Release:  * dev Operating System:  * GNU/Linux
Fixed Release:  None Planned Release:  None
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Wed 15 Nov 2017 11:00:42 PM UTC, comment #3: 

I checked in the fix here http://hg.savannah.gnu.org/hgweb/octave/rev/599fe61a5619.

I also added a file leftdiv.tst in the test/ directory to test some of these corner cases so we don't accidentally revert changes.

Rik <rik5>
Group administrator
Tue 14 Nov 2017 09:04:50 AM UTC, comment #2: 

I forgot the complex cases, new patch lssolve.diff2.

(file #42395)

Marco Caliari <caliari>
Group Member
Tue 14 Nov 2017 08:43:50 AM UTC, comment #1: 

The patch wrt default.

(file #42394)

Marco Caliari <caliari>
Group Member
Tue 14 Nov 2017 08:42:37 AM UTC, original submission:  

If you try


[Inf, 0;0, 0] \ [1; 1]


you get zeros (2) as a result. The problem is fixed by the attached patch. The new result ([0; 0]) is consistent with


[realmax, 0;0, 0] \ [1; 1]
diag ([Inf, 0]) \ [1; 1]


and different from Matlab [0; Inf], but I think this is known.
In the function lssolve, I do not understand the need of the two variables nrhs and b_nc. I think one in enough.

Marco Caliari <caliari>
Group Member

 

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Attached Files
file #42395:  lssolve.diff2 added by caliari (2KiB - application/octet-stream)
file #42394:  lssolve.diff added by caliari (1KiB - application/x-tex)

 

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Items that depend on this one: None found

 

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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2017-11-15 rik5 StatusPatch Submitted Fixed
        Open/ClosedOpen Closed
    2017-11-14 caliari Attached File- Added lssolve.diff2, #42395
    2017-11-14 caliari Attached File- Added lssolve.diff, #42394

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