# How to calculate Finite Strain Tensor using Python Calculator?

**URL:** https://discourse.paraview.org/t/how-to-calculate-finite-strain-tensor-using-python-calculator/11383
**Category:** ParaView Support
**Tags:** python, vtk
**Created:** [February 12, 2023, 11:34pm UTC](https://discourse.paraview.org/t/how-to-calculate-finite-strain-tensor-using-python-calculator/11383 "2023-02-12T23:34:14Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Gening\_Dong](https://discourse.paraview.org/user_avatar/discourse.paraview.org/gening_dong/32/10295_2.png) [@Gening\_Dong](https://discourse.paraview.org/u/Gening_Dong)
#### Post date: [February 12, 2023, 11:34pm UTC](https://discourse.paraview.org/t/how-to-calculate-finite-strain-tensor-using-python-calculator/11383/1 "2023-02-12T23:34:14Z")

</div>

Hi,

I’d like to calculate the large deformation strain tensor in a 3D deforming model. The formula is as follows:

 ![Screenshot 2023-02-12 182825](https://discourse.paraview.org/uploads/default/original/2X/e/ed2b15dfb1f1d5345ca9da5fcae40a88796509de.jpeg)

where x’ is the reference/initial coordinate, and the deformed coordinate x = x’ + u. I tried with `Compute Derivates` and `Gradients` filter, however, I think these 2 filters can only take derivates of the deformed coordinates x. Is there a way to take derivates of x’?  
I used the `Calculator` filter to compute x’ = x - u, but I cannot find a function in both `Calculator` and `Python Calculator` with can let me compute du/dx’. Anyone has any ideas?

Thanks in advance,  
Gening