# PythonCalculator: problem with division per volume(dataset)

**URL:** https://discourse.paraview.org/t/pythoncalculator-problem-with-division-per-volume-dataset/5959
**Category:** ParaView Support
**Created:** [December 2, 2020, 2:46pm UTC](https://discourse.paraview.org/t/pythoncalculator-problem-with-division-per-volume-dataset/5959 "2020-12-02T14:46:05Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Andrea](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@Andrea](https://discourse.paraview.org/u/Andrea)
#### Post date: [December 2, 2020, 2:46pm UTC](https://discourse.paraview.org/t/pythoncalculator-problem-with-division-per-volume-dataset/5959/1 "2020-12-02T14:46:05Z")

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Hi,

I’m using paraview on linux, I have installed numpy, and I am importing data from openfoam8. I have a scalar field (called T) and a mesh.  
On paraview guide it is written that “volume (dataset)” is the cell volume field; what i want to do is divide T per cell volume, but if I write " T/ volume (dataset)" in pythoncalculator it generatse the error “dataset is not defined”, so how could I define the dataset?  
T is a scalar field that represent number of particles, so i’m trying to calculate the particle concentrations.  
Please tell me if you need more information; I’m not very expert with paraview and I have never programmed in python.