[Paraview] storing output calculated by python running in parallel - write to a file? (UNCLASSIFIED)

[Su, Simon M CTR USARMY ARL (US)]

Classification: UNCLASSIFIED
Caveats: NONE

Hi Utkarsh,

Yes that is exactly what I wanted to do. I am using the programmable filter to 
add up all the values for a cell/point variable by iterating through the 
number of cells/points using python loop and write out the sum. Is there an 
example on how to do this? How will I format the output before writing it to 
the file? In my script below which you helped with last week, how would you 
have the paraview.simple.CreateWriter() class to write out just the sum 
variable?

Thank you very much
-simon




def calculateSum(input, output):
    # Copy the cells etc.
    output.ShallowCopy(input)

    # Get the array to calculate the coefficient
    toSum = output.GetPointData().GetArray("MOMENT_X")

    # for each of the elements, calculate the three roots and store the real 
and imaginary output in separate arrays
    numPoints = toSum.GetSize()

    tsum = 0

    for i in range(0, numPoints):
        tsum = tsum + toSum.GetValue(i)
    return tsum


input = self.GetInputDataObject(0, 0)
output = self.GetOutputDataObject(0)
sum = 0

print sum
if input.IsA("vtkUniformGridAMR"):
    # This initializes AMR properly. It will share the dataset instances
    # but we will clone those later.
    output.ShallowCopy(input)

    iter = input.NewIterator()
    iter.UnRegister(None)
    iter.InitTraversal()
    while not iter.IsDoneWithTraversal():
        curInput = iter.GetCurrentDataObject()
        curOutput = curInput.NewInstance()
        sum = sum + calculateSum(curInput, curOutput)
        output.SetDataSet(iter, curOutput)
        curOutput.UnRegister(None)
        iter.GoToNextItem();
else:
    sum = sum + calculateSum(input, output)

# write sum to file
writer = CreateWriter('foo.csv')
......







-----Original Message-----
From: Utkarsh Ayachit [mailto:utkarsh.ayachit at kitware.com]
Sent: Monday, July 07, 2014 11:36 AM
To: Su, Simon M CTR USARMY ARL (US)
Cc: paraview at paraview.org
Subject: Re: [Paraview] storing output calculated by python running in 
parallel - write to a file? (UNCLASSIFIED)

Simon,

If you're saving out data generated by a pipeline (which can include 
Programmable filter or Python calculator), then you should use
CreateWriter(http://www.paraview.org/ParaView3/Doc/Nightly/www/py-doc/paraview.simple.html#paraview.simple.CreateWriter)
to create a writer and then write the data out -- akin to "Save Data"
in ParaView.

Utkarsh

On Mon, Jul 7, 2014 at 11:30 AM, Su, Simon M CTR USARMY ARL (US) 
<simon.m.su.ctr at mail.mil> wrote:
> Classification: UNCLASSIFIED
> Caveats: NONE
>
> Hello,
>
> In my python script (ran using pvbatch mypythonscript.py in parallel
> environment), how do I save out the data I calculated to a file? How
> will be parallel execution affect the writing of the output to a file
> (which process will be doing the writing)?
>
> In a none parallel mode, this is what I want to do which write the
> output to out.txt file.
>
> f = open('out.txt', 'w')
> print >> f, 'Filename:', filename  # or f.write('...\n')
> f.close()
>
> what is the parallel equivalent of that?
>
> Any help is much appreciated.
>
> Thanks
> -simon
>
>
>
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
>
>
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Classification: UNCLASSIFIED
Caveats: NONE


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