[Paraview] Quadrature in Paraview

Thu Mar 28 03:43:29 EDT 2013

I am trying to understand quadrature in paraview.  I am running finite element simulations in which I have displacements at the nodes of the element, and stress/strain at the quadrature points.  I have linear and quadratic hexahedral or tetrahedral elements.  I have been spending days trying to figure out how to implement data on the quadrature points.  I have downloaded just about every document I can find.
First:  I downloaded CylinderQuadratic.vtk as shown in VTK-Quadrature-Point-Design-Doc.  I was able to generate the quadrature scheme dictioanary and generate quadrature points.  But, when I tried to use the Interpolate to Quadrature Points filter I could not select QuadratureOffset in the Select Source Array drop down menu.  I was able to do this when using the Generate Quadrature Points filter.  
Second:  Considering I couldn't figure out how to interpolate quadrature points using CylinderQuadratic.vtk, I decided to investigate just using a single element.  I took quadraticTetra01.vtu and modified it to only have on quadratic tetrahedron.  Then I used paraview to generate the quadrature scheme dictionary.  I saved this into a VTU file in order to see how to implement the dictionary on my own.  When I tried to reopen this new VTU file, paraview was unable to open the file.  Specifically, it choked on the QuadratureOffset data array.This is the file that paraview cannot open
<VTKFile type="UnstructuredGrid" version="0.1" byte_order="LittleEndian">  <UnstructuredGrid>    <Piece NumberOfPoints="10" NumberOfCells="1">      <PointData Scalars="scalars">        <DataArray type="Float32" Name="scalars" format="ascii" RangeMin="0" RangeMax="1">          1 1 1 1 0 0          0 0 0 0        </DataArray>      </PointData>      <CellData>        <DataArray type="Int64" Name="QuadratureOffset" format="ascii" RangeMin="0" RangeMax="0">        <InformationKey name="DICTIONARY" location="vtkQuadratureSchemeDefinition">          <vtkQuadratureSchemeDefinition>            <CellType value="24">                          </CellType>            <NumberOfNodes value="10">                          </NumberOfNodes>            <NumberOfQuadraturePoints value="4">                          </NumberOfQuadraturePoints>            <ShapeFunctionWeights>              1.5625000000000000e-001 -9.3750000000000000e-002 -9.3750000000000000e-002 -9.3750000000000000e-002              3.1250000000000000e-001 6.2500000000000000e-002 3.1250000000000000e-001 3.1250000000000000e-001              6.2500000000000000e-002 6.2500000000000000e-002 -9.3750000000000000e-002 7.0312500000000000e-002              -1.1718750000000000e-001 -9.3750000000000000e-002 2.8125000000000000e-001 4.2187500000000000e-001              9.3750000000000000e-002 6.2500000000000000e-002 2.8125000000000000e-001 9.3750000000000000e-002              -9.3750000000000000e-002 -1.1718750000000000e-001 7.0312500000000000e-002 -9.3750000000000000e-002              9.3750000000000000e-002 4.2187500000000000e-001 2.8125000000000000e-001 6.2500000000000000e-002              9.3750000000000000e-002 2.8125000000000000e-001 -9.3750000000000000e-002 -5.4687500000000000e-002              -5.4687500000000000e-002 3.7500000000000000e-001 3.1250000000000000e-002 1.5625000000000000e-002              3.1250000000000000e-002 3.7500000000000000e-001 1.8750000000000000e-001 1.8750000000000000e-001            </ShapeFunctionWeights>            <QuadratureWeights>              2.1219962781139991e-314 2.1219957914593380e-314 1.1013158155129526e-311 1.1501217187461613e-311            </QuadratureWeights>                      </vtkQuadratureSchemeDefinition>                  </InformationKey>          0        </DataArray>      </CellData>      <Points>        <DataArray type="Float32" Name="Points" NumberOfComponents="3" format="ascii" RangeMin="0" RangeMax="1.1874342107">          0 0 0 1 0 0          0.5 0.80000001192 0 0.5 0.40000000596 1          0.5 0 -0.20000000298 0.60000002384 0.60000002384 0          0.30000001192 0.40000000596 0 0.40000000596 0.20000000298 0.5          0.85000002384 0.30000001192 0.5 0.5 0.60000002384 0.44999998808        </DataArray>      </Points>      <Cells>        <DataArray type="Int64" Name="connectivity" format="ascii" RangeMin="0" RangeMax="9">          0 1 2 3 4 5          6 7 8 9        </DataArray>        <DataArray type="Int64" Name="offsets" format="ascii" RangeMin="10" RangeMax="10">          10        </DataArray>        <DataArray type="UInt8" Name="types" format="ascii" RangeMin="24" RangeMax="24">          24        </DataArray>      </Cells>    </Piece>  </UnstructuredGrid></VTKFile>

Third:  I investigated quadrature for hexahedron.  I made a similar file to quadraticTetra01.vtu and tried to generate a quadrature dictionary.  Upon hitting apply for this, paraview crashes.  It crashes for both linear and quadratic hexahedron. This is the file it crashes on,
<?xml version="1.0"?><VTKFile type="UnstructuredGrid" version="0.1" byte_order="LittleEndian" compressor="vtkZLibDataCompressor">  <UnstructuredGrid>    <Piece NumberOfPoints="12" NumberOfCells="2">      <PointData Scalars="scalars">        <DataArray type="Float32" Name="scalars" format="ascii">          1 1 1 1 0 0 0 0 0 0 1 1        </DataArray>      </PointData>	        <Points>        <DataArray type="Float32" NumberOfComponents="3" format="ascii">         -1.0 -1.0 1.0         -1.0 -1.0 -1.0         -1.0 1.0 -1.0         -1.0 1.0 1.0         1.0 -1.0 1.0         1.0 -1.0 -1.0         1.0 1.0 -1.0         1.0 1.0 1.0		 3.0 -1.0 1.0         3.0 -1.0 -1.0         3.0 1.0 -1.0         3.0 1.0 1.0        </DataArray>      </Points>      <Cells>        <DataArray type="Int32" Name="connectivity" format="ascii">          0 1 2 3 4 5 6 7		  4 5 6 7 8 9 10 11        </DataArray>		<DataArray type="Int32" Name="offsets" format="ascii">          8 16        </DataArray>        <DataArray type="UInt8" Name="types" format="ascii">          12 12        </DataArray>      </Cells>    </Piece>  </UnstructuredGrid></VTKFile>

My question is can anyone give me a quick example to implement quadrature in paraview.  I am at wits end trying to figure this out.  

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