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IDProjectCategoryView StatusDate SubmittedLast Update
0006706ParaView(No Category)public2008-04-02 11:082009-05-13 13:59
ReporterKen Moreland 
Assigned ToBerk Geveci 
PrioritynormalSeveritycrashReproducibilityhave not tried
StatusclosedResolutionfixed 
PlatformOSOS Version
Product Version 
Target Version3.4Fixed in Version3.4 
Summary0006706: Gradient and Gradient Magnitude filters only work on
DescriptionThe object inspector for the Gradient and Gradient Magnitude filter allows you to select the input scalars by name, but the selection has no effect. These two filters always grab the active scalars on the input image data. This leads to two serious problems.

1. The gradients computed may not correspond to the input the user selected, leading to very misleading results.

2. If the input has no active scalars, the filters will create a new array in the input in an attempt to get them. This leads to garbage in the output and breaks an assumption that the input will not be modified by the filter. The broken assumption often leads to crashes in ParaView in strange places.
Steps To ReproduceThe attached file has no active scalars defined in it. If you run either gradient filter, you will get garbage for the gradients (assuming it does not crash in the process). If it does not crash, it is not hard to get ParaView to crash after the fact. Playing with scalar bars or deleting the pipeline objects usually does the trick.
Additional InformationI understand that this behavior is typical of the imaging pipeline objects. We should check to make sure that there are no more filters used by ParaView that exhibit this behavior.
TagsNo tags attached.
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Topic Name
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Attached Files? file icon NoActiveScalars.vti [^] (28,685 bytes) 2008-04-02 11:08

 Relationships
child of 0006693closedBerk Geveci Add result array name feature to gradient and gradient magnitude filters 

  Notes
(0011035)
Ken Moreland (manager)
2008-04-02 11:17

 Rather than change the gradient filters themselves, it may be prudent to create a meta-filter that uses the imaging filters internally but uses shallow copies of data objects to convert the ParaView array naming convention to the imaging pipeline active scalars convention.

I can see two potential forms for this filter. One form would be a generic filter that worked on some unspecified image algorithm (in a manner similar to vtkFileSeriesReader). Another form would be a specific filter that used either the image gradient filter or the unstructured gradient filter, depending on the input type.
(0011036)
Ken Moreland (manager)
2008-04-02 11:19

 Is it really necessary to have the Gradient Magnitude filter? The functionality could more-or-less be replaced with the Gradient filter and the Calculator filter to compute the magnitude. Would anyone have any heartburn if Gradient Magnitude went away?
(0013036)
Berk Geveci (administrator)
2008-08-15 11:31

 Waiting for feedback from Ken.
(0013154)
Berk Geveci (administrator)
2008-08-22 13:06

 Gradient now works on any selected arrays. I deprecated (removed) gradient magnitude based on our decision.
(0013261)
Alan Scott (manager)
2008-09-02 21:14

 Assumed fixed.

 Issue History
Date Modified Username Field Change
2008-04-02 11:08 Ken Moreland New Issue
2008-04-02 11:08 Ken Moreland File Added: NoActiveScalars.vti
2008-04-02 11:09 Ken Moreland Relationship added child of 0006693
2008-04-02 11:17 Ken Moreland Note Added: 0011035
2008-04-02 11:19 Ken Moreland Note Added: 0011036
2008-04-10 18:00 Ken Moreland Category Development => 3.4
2008-04-10 18:00 Ken Moreland Status backlog => tabled
2008-04-10 18:00 Ken Moreland Assigned To => Berk Geveci
2008-08-15 11:31 Berk Geveci Note Added: 0013036
2008-08-15 11:31 Berk Geveci Status tabled => @20@
2008-08-22 13:06 Berk Geveci Status @20@ => @80@
2008-08-22 13:06 Berk Geveci Resolution open => fixed
2008-08-22 13:06 Berk Geveci Note Added: 0013154
2008-09-02 21:14 Alan Scott Status @80@ => closed
2008-09-02 21:14 Alan Scott Note Added: 0013261
2009-05-13 13:58 Utkarsh Ayachit Target Version => 3.4
2009-05-13 13:59 Utkarsh Ayachit Fixed in Version => 3.4
2011-06-16 13:10 Zack Galbreath Category => (No Category)

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