[Paraview] Help with Programmable Filter

[Casey Goodlett]

Hi Dennis,

I took a look at the filter to see what might be wrong, but I seem to be
missing a couple of things:

1) Are you using the "Copy Arrays" option of the programmable filter?
Otherwise you will need to reference the input data as well.

2) Where are the P1,P2,P3, etc vectors created?  What type are they?

The below script worked for me if Copy Arrays is enabled.  I used the
can.ex2 example dataset from paraview and ensured the "Object Ids" cell
data was selected in the reader.

for oblock in output:

   oid = oblock.CellData['ObjectId']

   o2 = oid + 10

   oblock.CellData.append(o2, 'newdata')

Hope that helps


On Mon, Aug 4, 2014 at 3:21 PM, Dennis Conklin <dennis_conklin at goodyear.com>
wrote:

>  I have the following script for a Paraview Programmable filter:
>
>
>  import math
> import numpy
>
>  #
> #  Gdyr_Principal_Strains_ProgFilter
> #    Rev 0
> #    Aug 1, 2014
> #  Dennis Conklin - Engineering Mechanics
> #
> #  Paraview 4.0.1 Progammable Filter
> #  Adds Cell Variables:
> #      Principal Strains:  str_P1, str_P2, str_P3
> #      max shear strain:   tau_max
> #  These can be used for coloring, Spreadsheet view, formulas, threshold,
> etc
> #
> def process_block(block):
>    #
>    # Global coordinate strains
>    # Assume strains loaded in Paraview
>    xx = block.CellData['USTRTOTXX']
>    yy = block.CellData['USTRTOTYY']
>    zz = block.CellData['USTRTOTZZ']
>    xy = block.CellData['USTRTOTXY']
>    xz = block.CellData['USTRTOTZX']
>    yz = block.CellData['USTRTOTYZ']
>
>     for i in range(block.GetNumberOfCells()
>       sigma = numpy.array([ [xx[i],xy[i],xz[i]],
>                             [xy[i],yy[i],yz[i]],
>                             [xz[i],yz[i],zz[i]]
>                          ])
>
>        # isotropic strain matrix
>       iso = 1.0/3.0*numpy.trace(sigma)*numpy.eye(3)
>       # deviatoric strain matrix
>       dev = sigma - iso
>
>       #principal strains
>       eigvals = list(numpy.linalg.eigvalsh(sigma))
>       eigvals.sort()
>       eigvals.reverse()
>       P1[i] = eigvals[0]
>       P2[i] = eigvals[1]
>       P3[i] = eigvals[2]
>       # max shear
>       max_shear[i] = (max(eigvals)-min(eigvals))/2.0
>
>    block.CellData.append(P1,"P1_strain")
>    block.CellData.append(P2,"P2_strain")
>    block.CellData.append(P3,"P3_strain")
>    block.CellData.append(max_shear,"tauMax")
>
>
>  # Loop over blocks in composite (Exodus) data set
> for block in output:
>    # process each block
>    process_block(block)
>
> After running this script, no errors or warnings are issued but the
> additional quantites (taumax, Px_strain) are not present as element
> quantities.
>
>  Any hints as to what I'm doing wrong.
>
>
>   Dennis Conklin, PE
> RDE&Q Senior Engineer
> Goodyear Innovation Center, 5th Floor South, Pillar M34
> Phone:  330-796-5701
> Email:  dennis_conklin at goodyear.com
>
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-- 
Casey B. Goodlett, Ph.D.
Technical Leader
Kitware, Inc. - North Carolina Office
http://www.kitware.com
(919) 969-6990 x310
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