Help with vtkInterpolateDataSetAttributes

"Andrew E. Slaughter via vtkusers" <[email protected]> Thu, 29 Nov 2018 16:13:28 +0000

Newsgroups	gmane.comp.lib.vtk.user
Message-ID	<[email protected]>

I am attempting to interpolate between two ExodusII (vtkExodusIIReader) results using the vtkInterpolateDataSetAttributes, but am having trouble getting it to work. I was able to perform an interpolation that mimics the behavior with calls to vtkAbstractArray::InterpolateTuple, but this doesn’t seem like the correct solution.

I have attached a script that show what I am trying to do, including what is working and what is not. I know that for this problem I could use vtkTemporalInterpolator, but for the actual problem I am trying to solve it isn’t appropriate. I am using python bindings with VTK7.1 on MacOS.

I would appreciate any help I can get making this work.

Thanks,
Andrew

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input_no_adapt_out.e (application/octet-stream, 35.7 KB) - not displayed

interpolate_data_set.py (text/x-python-script, 2 KB)

#!/usr/bin/env python
import vtk

filename = 'input_no_adapt_out.e'
variable = 'u'
drange = [0, 10]

reader0 = vtk.vtkExodusIIReader()
reader0.SetFileName(filename)
reader0.UpdateInformation()
reader0.SetTimeStep(0)
reader0.SetAllArrayStatus(vtk.vtkExodusIIReader.NODAL, 1)
reader0.Update()

data0 = reader0.GetOutput().GetBlock(0).GetBlock(0)
print data0.GetPointData().GetAbstractArray(0).GetRange() # [0, 5]

reader1 = vtk.vtkExodusIIReader()
reader1.SetFileName(filename)
reader1.UpdateInformation()
reader1.SetTimeStep(1)
reader1.SetAllArrayStatus(vtk.vtkExodusIIReader.NODAL, 1)
reader1.Update()

data1 = reader1.GetOutput().GetBlock(0).GetBlock(0)
print data1.GetPointData().GetAbstractArray(0).GetRange() # [0, 14]

# How do I get this working?
interpolator = vtk.vtkInterpolateDataSetAttributes()
interpolator.AddInputData(reader0.GetOutput().GetBlock(0).GetBlock(0))
interpolator.AddInputData(reader1.GetOutput().GetBlock(0).GetBlock(0))
interpolator.SetT(0.5)
interpolator.Update()
print interpolator.GetOutput().GetPointData().GetAbstractArray(0)#.GetRange() # [0, 9.5]

# How do I get this working? This is what happens with the vtkInterpolateDataSetAttributes
n = data0.GetPointData().GetNumberOfTuples()
data = vtk.vtkPointData()
data.InterpolateAllocate(data0.GetPointData())
for i in xrange(n):
    data.InterpolateTime(data0.GetPointData(),
                         data1.GetPointData(),
                         i,
                         0.5)
print data.GetAbstractArray(0).GetRange() # [0, 9.5]

# THIS WORKS!
data = vtk.vtkPointData()
data.CopyStructure(data0.GetPointData())
data.SetNumberOfTuples(n)
for i in xrange(data.GetNumberOfTuples()):
    data.GetAbstractArray(0).InterpolateTuple(i,
                                              i, data0.GetPointData().GetAbstractArray(0),
                                              i, data1.GetPointData().GetAbstractArray(0),
                                              0.5)
print data.GetAbstractArray(0).GetRange() # [0, 9.5]