bugGNU Octave - Bugs: bug #34334, symrcm order is not reversed

 
 

bug #34334: symrcm order is not reversed

Submitter:  None
Submitted:  Mon 19 Sep 2011 10:13:07 PM UTC
   
 
Category:  Octave Function Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Need Info Assigned to:  None
Originator Name:  Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * 3.4.2
Operating System:  * Any Fixed Release:  None
Planned Release:  None
* Mandatory Fields

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Sun 22 Feb 2015 06:16:34 AM UTC, comment #3: 

No response to request for more information in over a year. Closing inactive bug report.

Mike Miller <mtmiller>
Group Member
Sun 19 Jan 2014 10:56:53 PM UTC, comment #2: 

This bug report needs an example or data test case attached. Please show what the expected behavior is and what the actual behavior in Octave is. Also would be best if you could show what the actual behavior calling the same functions in Matlab is.

Mike Miller <mtmiller>
Group Member
Mon 19 Sep 2011 10:13:07 PM UTC, comment #1: 

This item has been reassigned from the project GNU Octave patch tracker to your tracker.

The original report is still available at patch #7605

Following are the information included in the original report:

[field #0]                  Item ID: 7605
[field #1]                 Group ID: 1925
[field #2]              Open/Closed: Open
[field #3]                 Severity: 3 - Normal
[field #4]                  Privacy: Public
[field #7]                         : Unknown patch Field Display Type
[field #8]                         : Unknown patch Field Display Type
[field #9]                 Category: None
[field #10]             Submitted by: None
[field #11]              Assigned to: None
[field #12]             Submitted on: Thu 25 Aug 2011 09:39:44 AM GMT
[field #13]                  Summary: symrcm order is not reversed
[field #14]      Original Submission: the sparse matrix function symrcm appears to produce results in non-reversed Cuthill-McKee ordering rather than reverse Cuthill-McKee (compare to MATLAB symrcm with spy). This makes a big difference for FEM solution of Navier-Stokes with Taylor-Hood elements via gmres (Octave 3.4.2) -- non-reversed ordering produces poor matrix conditioning, reverse ordering works properly (verified in both MATLAB and Octave). Direct solutions (mldivide) are not impacted however. Please update symrcm (possibly with fliplr or flipud of the result).
[field #16]               Item Group: None
[field #17]                   Status: None
[field #18]        Component Version: None
[field #19]         Operating System: None
[field #20]          Reproducibility: None
[field #21]               Size (loc): None
[field #22]            Fixed Release: None
[field #23]          Planned Release: None
[field #24]                   Effort: 0.00
[field #28]                 Priority: 5 - Normal
[field #31]         Percent Complete: 0%
[field #33]                  Release: None
[field #58]     Custom Select Box #1: None
[field #59]     Custom Select Box #2: None
[field #60]     Custom Select Box #3: None
[field #61]     Custom Select Box #4: None
[field #62]     Custom Select Box #5: None
[field #63]     Custom Select Box #6: None
[field #64]     Custom Select Box #7: None
[field #65]     Custom Select Box #8: None
[field #66]     Custom Select Box #9: None
[field #67]    Custom Select Box #10: None

Jordi GutiƩrrez Hermoso <jordigh>
Group Member
Mon 19 Sep 2011 10:13:07 PM UTC, original submission:  

the sparse matrix function symrcm appears to produce results in non-reversed Cuthill-McKee ordering rather than reverse Cuthill-McKee (compare to MATLAB symrcm with spy). This makes a big difference for FEM solution of Navier-Stokes with Taylor-Hood elements via gmres (Octave 3.4.2) -- non-reversed ordering produces poor matrix conditioning, reverse ordering works properly (verified in both MATLAB and Octave). Direct solutions (mldivide) are not impacted however. Please update symrcm (possibly with fliplr or flipud of the result).

Anonymous

 

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  • -email is unavailable- added by mtmiller (Posted a comment)
  • -email is unavailable- added by jordigh (Updated the item)
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    Follow 7 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2015-02-22 mtmiller Open/ClosedOpen Closed
    2014-01-19 mtmiller CategoryNone Octave Function
        Item GroupNone Incorrect Result
        StatusNone Need Info
    2011-09-19 jordigh ReleaseNone 3.4.2
        Operating SystemNone Any
    2011-09-19 jordigh Reassign itemGNU Octave, patch #7605 GNU Octave, bug #34334

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