# Iterate through tensor in paraview programable filter
**URL:** https://discourse.paraview.org/t/iterate-through-tensor-in-paraview-programable-filter/12290
**Category:** ParaView Support
**Created:** [June 12, 2023, 12:43pm UTC](https://discourse.paraview.org/t/iterate-through-tensor-in-paraview-programable-filter/12290 "2023-06-12T12:43:47Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Trailer1](https://discourse.paraview.org/u/Trailer1)
#### Post date: [June 12, 2023, 12:43pm UTC](https://discourse.paraview.org/t/iterate-through-tensor-in-paraview-programable-filter/12290/1 "2023-06-12T12:43:47Z")
Hello,
I would like to iterate over a tensor in paraview to compute its eigenvalues and eigenvectors. But currently I am unable to do so.
I have:
```auto
import numpy as np
input0 = inputs[0]
data = input0.CellData["tau"]
nCells = input0.GetNumberOfCells()
eigenVals = np.zeros((nCells, 3))
eigVecs= np.zeros((nCells, 3, 3))
for i in range(nCells):
T = # How can I get the numpy array representing the data?
eigenVals[i], eigVecs[i] =np.linalg.eig(T)
output.CellData.append(eigVals,"eigenValues")
output.CellData.append(eigVecs,"eigenVectors")
```
How can I fix this?
---
### Author:  [@Trailer1](https://discourse.paraview.org/u/Trailer1)
#### Post date: [June 14, 2023, 4:38pm UTC](https://discourse.paraview.org/t/iterate-through-tensor-in-paraview-programable-filter/12290/2 "2023-06-14T16:38:36Z")
Anyone that can help with how to iterate over a field in paraview?
---
### Author:  [@Sanjay\_GOVINDJEE](https://discourse.paraview.org/u/Sanjay_GOVINDJEE)
#### Post date: [June 17, 2023, 1:03pm UTC](https://discourse.paraview.org/t/iterate-through-tensor-in-paraview-programable-filter/12290/3 "2023-06-17T13:03:21Z")
How about
`T = np.array( data[i,:,:] )`