# Programmable Filter Error

**URL:** https://discourse.paraview.org/t/programmable-filter-error/3192
**Category:** ParaView Support
**Tags:** python
**Created:** [December 16, 2019, 5:12pm UTC](https://discourse.paraview.org/t/programmable-filter-error/3192 "2019-12-16T17:12:41Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Alexandros](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/a/ecc23a/32.png) [@Alexandros](https://discourse.paraview.org/u/Alexandros)
#### Post date: [December 16, 2019, 5:12pm UTC](https://discourse.paraview.org/t/programmable-filter-error/3192/1 "2019-12-16T17:12:41Z")

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Hello everyone, I am new to paraview -and python, my question is the following:  
I opened a pipeline dataset read by paraview from corresponding xdmf file, then I applied calculator filter twice to calculate two quantities. Then I use the filter group datasets to group together the results of the calculator filters. Next I would like to create a programmable filter just like the one described in the paraview guide. I follow the script instructions:

input0 = inputs[0]  
dataArray = input0.PointData[“v”]/2.0  
output.PointData.append(dataArray, “V\_half”)

However the following error message appears that I wasn’t able to resolve:  
NameError: name ‘RequestData’ is not defined. I choose my output as ,same as input, as described in the guide. Can someone please explain what is happening?  
I am using paraview 5.7.

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### Author: ![utkarsh.ayachit](https://discourse.paraview.org/user_avatar/discourse.paraview.org/utkarsh.ayachit/32/39_2.png) [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [December 16, 2019, 9:17pm UTC](https://discourse.paraview.org/t/programmable-filter-error/3192/2 "2019-12-16T21:17:42Z")

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Are there any other error messages? Attached is a state file I tried to create using the Wavelet source and it seems to work without any issues.

[foo.pvsm](https://discourse.paraview.org/uploads/short-url/djGIzS7aqBUM1HF774gF1Hbqku5.pvsm) (339.5 KB)

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### Author: ![Alexandros](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/a/ecc23a/32.png) [@Alexandros](https://discourse.paraview.org/u/Alexandros)
#### Post date: [January 14, 2020, 1:51pm UTC](https://discourse.paraview.org/t/programmable-filter-error/3192/3 "2020-01-14T13:51:51Z")

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Although I am late to reply, Thank you very much for sharing the file! Thanks to it I managed to find my error.