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IDProjectCategoryView StatusDate SubmittedLast Update
0012331VTK(No Category)public2011-07-03 21:442013-12-13 10:05
ReporterPeter Wood 
Assigned ToDave DeMarle 
PrioritynormalSeverityminorReproducibilityhave not tried
StatusclosedResolutionfixed 
PlatformOSOS Version
Product Version 
Target VersionFixed in Version6.1.0 
Summary0012331: Tolerance problem in 'vtkImplicitDataSet::EvaluateFunction': 'tol2' set as 0.0, which appears to be too tight
DescriptionTolerance problem in 'vtkImplicitDataSet.cxx' in method
'EvaluateFunction' line 81, as follows

"""
// Find the cell that contains xyz and get it
cell = this->DataSet->FindAndGetCell(x,NULL,-1,0.0,subId,pcoords,this->Weights);
                                               ^^^
"""

Note 4th parameter '0.0'. This is 'tol2' in API, which is used in
'vtkPointSet.cxx' in method 'FindCellWalk'

"""
    double dist2;
    if ( (cell->EvaluatePosition(x, closestPoint, subId,
                                   pcoords, dist2, weights) == 1)
        && (dist2 <= tol2) )
      {
      return cellId;
      }
"""

The problem is that 'tol2' is 0.0, but often 'dist2' may be calculated
to be approx 1e-032 to 1e-029, a very small number, but still greater
than 0.0! (NB: I adapted vtkPointSet.cxx to report 'dist2')

To fix this problem, when calling 'FindAndGetCell' in
'vtkImplicitDataSet' replace '0.0' with an appropriate small positive
tolerance value, e.g. '1e-16'. This could be user-configurable?
TagsNo tags attached.
ProjectTBD
Typeincorrect functionality
Attached Files? file icon test_vtkImplicitDataSet_tol2_problem.py [^] (2,732 bytes) 2011-07-03 21:44

 Relationships

  Notes
(0026947)
Peter Wood (reporter)
2011-07-03 22:43

One option may be to replace '0.0' with VTK_DBL_EPSILON ?
(0030898)
Jean-Christophe Fillion-Robin (manager)
2013-06-05 13:20

Does the problem still occur with VTK 5.10 ? VTK 6 ?

Would be great if you could submit a patch using Gerrit. For more details see http://www.vtk.org/Wiki/VTK/Git/Develop [^]

Thanks
Jc
(0031928)
Dave DeMarle (administrator)
2013-12-13 10:05

http://review.source.kitware.com/#/t/3022/ [^]
merged

 Issue History
Date Modified Username Field Change
2011-07-03 21:44 Peter Wood New Issue
2011-07-03 21:44 Peter Wood File Added: test_vtkImplicitDataSet_tol2_problem.py
2011-07-03 22:43 Peter Wood Note Added: 0026947
2013-06-05 13:20 Jean-Christophe Fillion-Robin Note Added: 0030898
2013-12-13 10:05 Dave DeMarle Note Added: 0031928
2013-12-13 10:05 Dave DeMarle Status backlog => closed
2013-12-13 10:05 Dave DeMarle Assigned To => Dave DeMarle
2013-12-13 10:05 Dave DeMarle Resolution open => fixed
2013-12-13 10:05 Dave DeMarle Fixed in Version => 6.1.0


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