MantisBT - ParaView
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IDProjectCategoryView StatusDate SubmittedLast Update
0006837ParaView(No Category)public2008-04-17 07:022010-12-13 17:12
ReporterFilip Sadlo 
Assigned ToDave DeMarle 
PrioritynormalSeverityfeatureReproducibilityN/A
StatusclosedResolutionno change required 
PlatformOSOS Version
Product Version 
Target VersionSomedayFixed in Version 
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Type
Summary0006837: Detect if data on input port or widget has changed
DescriptionTo my knowledge there is no possibility to detect inside a filter if the data on an input port has not changed (e.g. only a widget has been modified). This would allow to skip dependent computation (e.g. initialization) and hence improve the efficiency of the module.

It would be nice to be able to detect if:
- the data on one of the (optional) input ports has changed
- the state of a parameter has changed
(AVS5 offers this functionality by AVSinput_changed() and AVSparameter_changed())

Additionally it would make sense to allow the filter programmer to declare that the data on an output port has not changed, in order to prevent subsequent modules from being triggered. (AVS5 offers this functionality by AVSmark_output_unchanged())
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Issue History
Date ModifiedUsernameFieldChange
2008-04-17 07:02Filip SadloNew Issue
2008-04-17 09:42Ken MorelandCategory3.4 => 3.6
2009-02-17 15:55Ken MorelandNote Added: 0015073
2009-02-17 15:55Ken MorelandCategory3.6 => Someday
2009-05-13 13:49Utkarsh AyachitTarget Version => Someday
2010-12-10 13:46Dave DeMarleNote Added: 0023875
2010-12-10 13:46Dave DeMarleStatusbacklog => @80@
2010-12-10 13:46Dave DeMarleResolutionopen => no change required
2010-12-10 13:46Dave DeMarleAssigned To => Dave DeMarle
2010-12-13 17:12Alan ScottNote Added: 0023942
2010-12-13 17:12Alan ScottStatus@80@ => closed
2011-06-16 13:10Zack GalbreathCategory => (No Category)

Notes
(0015073)
Ken Moreland   
2009-02-17 15:55   
Can't the filter cache keep around a reference to the last input object processed and its modified time and then just check to make sure that the pointer has not changed and the modified time has not changed?
(0023875)
Dave DeMarle   
2010-12-10 13:46   
This is exactly what the demand driven pipeline does. It only executes far enough upstream to get to the modified data.
(0023942)
Alan Scott   
2010-12-13 17:12   
I think Dave's answer is correct. If you disagree, please reopen this bug.