# How does the filter Integrate Variables work for Umag (velocity magnitude)?

**URL:** https://discourse.paraview.org/t/how-does-the-filter-integrate-variables-work-for-umag-velocity-magnitude/14979
**Category:** ParaView Support
**Created:** [July 4, 2024, 12:52am UTC](https://discourse.paraview.org/t/how-does-the-filter-integrate-variables-work-for-umag-velocity-magnitude/14979 "2024-07-04T00:52:21Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![vsaha](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/v/4491bb/32.png) [@vsaha](https://discourse.paraview.org/u/vsaha)
#### Post date: [July 4, 2024, 12:52am UTC](https://discourse.paraview.org/t/how-does-the-filter-integrate-variables-work-for-umag-velocity-magnitude/14979/1 "2024-07-04T00:52:21Z")

</div>

Hello, I am trying to understand how the Integrate Variables filter works on the velocity magnitude.

1. I created a slice and added Cell Size filter to it. Then, I exported it as a CSV.
2. Added Integrate Variables filter to the above, and confirmed that the result as indicated in the integrated column for Umag (velocity magnitude) and Area, are indeed correct.

When I check the CSV, the summation (sum) of the individual areas of all the cells does add up to the same value as in the Integrate Variables Area column. However, when I calculate an arithmetic mean (average) on the Umag column, it completely misses the mark when compared to the corresponing Integrate Variables result.

The Integrate Variables result is indeed correct, so my question is, how does Paraview go about applying the filter to Umag values? It is not simply a mean over all the values at least (as I confirmed by checking the CSV), so does it exclude some cells, for example boundary values, or applies an altogether different methodology?

Thanks and best regards!

---

<div class="post-metadata">

### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [July 4, 2024, 10:11am UTC](https://discourse.paraview.org/t/how-does-the-filter-integrate-variables-work-for-umag-velocity-magnitude/14979/2 "2024-07-04T10:11:29Z")

</div>

The U mag is usually computed on the fly.

You may want to share your data.

---

<div class="post-metadata">

### Author: ![vsaha](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/v/4491bb/32.png) [@vsaha](https://discourse.paraview.org/u/vsaha)
#### Post date: [July 5, 2024, 3:01am UTC](https://discourse.paraview.org/t/how-does-the-filter-integrate-variables-work-for-umag-velocity-magnitude/14979/3 "2024-07-05T03:01:10Z")

</div>

> [@mwestphal](#):
>
> your

Thank you for your reply. I understood the issue.  
(Divide cell by volume option gives the corrected result for velocity magnitude)  
(Unchecking the above option allows me to extract the total area of the slice, which I also need for my further calculations, so I will proceed with creating two separate integrate filters and proceed.)

Thanks and best regards