[Paraview] Quadrature in Paraview
Burlen Loring
bloring at lbl.gov
Mon Apr 1 13:02:04 EDT 2013
> One quick question though. Interpolate to quadrature points and
> generate quadrature points seems to be used for interpolating the
> nodal values and coloring the quadrature points appropriately. Is
> there anyway to have quadrature point data and then interpolate to the
> cell and color it appropriately.
not currently, someone would have to add a filter for this. Adding a
filter is too not a difficult a task.... ;-)
> Also FYI, Paraview still crashes when making the quadrature dictionary
> for hexahedral elements. It's probably not a big deal, I can make my
> own.
I suspect that you are trying to use the example dictionary generator
that's built into PV. However, this generator doesn't provide a
definition for hexahedral cells. Its primary purpose is to serve as an
example of how one write a dictionary generator. it was never intended
to be a comprehensive source of quadrature scheme definitions. The idea
with the dictionary generators is that practitioners would provide them
for their specific use cases. If my suspicion is incorrect, please give
some more detail about the crash? and any output in the terminal?
I also want to warn about using ascii format for large models, because
it's slow. The appended format is far better, although it may be
slightly more challenging to write your data that way if you're not
using vtk writers.
Glad you've had some success! The patches were merged over the weekend,
so you could use the nightly binaries now.
Burlen
On 03/31/2013 01:10 PM, afad sfgsfdgsfd wrote:
> Andy Bauer,
>
> Thank you for informing me about the nightly builds. I will keep that
> in mind from now on.
>
>
>
> Burlin Loring,
>
> So I implemented the patch and got everything compiled. I am now able
> to use all the quadrature filters and do the examples. Took me awhile
> because I was trying to compile for 64 bit when the qt libraries I
> downloaded were only 32 bit.
>
> One quick question though. Interpolate to quadrature points and
> generate quadrature points seems to be used for interpolating the
> nodal values and coloring the quadrature points appropriately. Is
> there anyway to have quadrature point data and then interpolate to the
> cell and color it appropriately. For example if I am using a linear
> element, stress would be constant in the cell, thus VTK would color
> each cell with constant stress. If I used quadratic elements, stress
> would be linear in each cell, thus VTK would color each cell linearly.
>
> Also FYI, Paraview still crashes when making the quadrature dictionary
> for hexahedral elements. It's probably not a big deal, I can make my
> own. But, Paraview does crash when attempting to do this.
>
> Thank you both so much for helping me, I really appreciate it.
>
>
> ------------------------------------------------------------------------
> Date: Fri, 29 Mar 2013 10:01:20 -0700
> From: bloring at lbl.gov
> To: deutchlobo at hotmail.com
> CC: paraview at paraview.org
> Subject: Re: [Paraview] Quadrature in Paraview
>
> Hi afad sfgsfdgsfd,
>
> Your example(quadratic tera) actually works with a very slight
> modification: move the cell offset data to the top of the element.
> That's clearly a bug in the reader(when reading inline data, the
> regression tests only check that the appended mode works, so that's
> why this bug slipped through.) . I attached the modified file so you
> see exactly what I meant.
>
> Burlen
>
> On 03/29/2013 09:43 AM, Burlen Loring wrote:
>
> Hi afad sfgsfdgsfd,
>
> Fixes for bugs introduced by changes in VTK's xml file format are
> in the pipeline, so you'll have to checkout the latest git HEAD
> and build ParaView from source to get the bug fixes. If that's
> something you're willing to do, here are first steps
>
> # get sources
> $ git clone --recursive git://www.paraview.org/ParaView.git
> # apply the patch
> # patch is attached and I just now submitted to PV, will show up
> in PV after the next review.
> $ cd ParaView
> $ git am -3 0001-QuadraturePoints-any-integer-type-for-offsets.patch
> # build pv
>
> That will get you the bug fixes. Build it, use default build opts
> is fine.
>
> Then if you like you can get the test data, and open the file
> ParaViewData/Data/blow.vtk, construct the pipeline showed in the
> post
> (http://markmail.org/message/6qz3ebszvny4vwxp#query:+page:1+mid:6qz3ebszvny4vwxp+state:results).
> That shows how it's supposed to work.
>
> $ git clone www.paraview.org/ParaViewData.git
> <http://www.paraview.org/ParaViewData.git>
>
> Now onto your data, the xml you gave is incorrect , it's missing
> the offset array. let me see if I can get your example working,
> I'll post a follow up, hopefully in a few minutes.
>
> Burlen
>
>
> On 03/28/2013 12:43 AM, afad sfgsfdgsfd wrote:
>
> 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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