# volSymmTensorFields Magnitude
**URL:** https://discourse.paraview.org/t/volsymmtensorfields-magnitude/15617
**Category:** ParaView Support
**Tags:** openfoam
**Created:** [October 23, 2024, 3:09am UTC](https://discourse.paraview.org/t/volsymmtensorfields-magnitude/15617 "2024-10-23T03:09:40Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Alimea](https://discourse.paraview.org/u/Alimea)
#### Post date: [October 23, 2024, 3:09am UTC](https://discourse.paraview.org/t/volsymmtensorfields-magnitude/15617/1 "2024-10-23T03:09:40Z")
Hi
I found that Paraview calculates a volSymmTensorFields Magnitude via the following relation:
```auto
tau_tot = (tau_xx^2 + tau_yy^2 + tau_zz^2 + tau_xy^2 + tau_xz^2 + tau_yz^2)^0.5
```
However, we know that the correct form of that is:
```auto
tau_tot = (tau_xx^2 + tau_yy^2 + tau_zz^2 + 2*tau_xy^2 + 2*tau_xz^2 + 2*tau_yz^2)^0.5
```
To check you can set the initial values of a volSymmTensorFields as (1 1 1 1 1 1). the mag of this tensor is 3. Now see its magnitude in paraview. You will see that it gives 2.45, not 3!
Could you please explain the reason?
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 23, 2024, 9:55am UTC](https://discourse.paraview.org/t/volsymmtensorfields-magnitude/15617/2 "2024-10-23T09:55:04Z")
> [@Alimea](#):
>
> volSymmTensorFields
Which filter compute this `volSymmTensorFields` ?
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### Author:  [@Alimea](https://discourse.paraview.org/u/Alimea)
#### Post date: [October 23, 2024, 10:06am UTC](https://discourse.paraview.org/t/volsymmtensorfields-magnitude/15617/3 "2024-10-23T10:06:52Z")
> [@Alimea](#):
>
> volSymmTensorFields
Actually, I computed `volSymmTensorFields` in OpenFOAM and I just wanted to see the results in paraView.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 23, 2024, 10:16am UTC](https://discourse.paraview.org/t/volsymmtensorfields-magnitude/15617/4 "2024-10-23T10:16:17Z")
ParaView compute the magnitude of any n-component array using the same formula, there is no specific case for symmetric tensors I’m afraid.
You can compute anything you want using the calculator though.
---
### Author:  [@Alimea](https://discourse.paraview.org/u/Alimea)
#### Post date: [October 23, 2024, 10:19am UTC](https://discourse.paraview.org/t/volsymmtensorfields-magnitude/15617/5 "2024-10-23T10:19:00Z")
Yes. I think this is from OpenFOAM nad is not related to paraView.