# Flag to check splitting

**URL:** <https://gpusph.discourse.group/t/flag-to-check-splitting/217>\
**Category:** Uncategorized\
**Created:** [November 8, 2024, 2:06pm UTC](https://gpusph.discourse.group/t/flag-to-check-splitting/217 "2024-11-08T14:06:20Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![AlirezaZarei](https://avatars.discourse-cdn.com/v4/letter/a/b5ac83/32.png) [@AlirezaZarei](https://gpusph.discourse.group/u/AlirezaZarei)\
**Post date:** [November 8, 2024, 2:06pm UTC](https://gpusph.discourse.group/t/flag-to-check-splitting/217/1 "2024-11-08T14:06:20Z")

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Hi Giuseppe,

I’m planning to split my domain to fully utilize the maximum capacity of the GPUs. Is there a flag or tool I can use to check the splitting and verify how the domain has been divided?

Thanks for your help!

Best regards,  
Alireza

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**Author:** ![giuseppe.bilotta](https://yyz2.discourse-cdn.com/free1/user_avatar/gpusph.discourse.group/giuseppe.bilotta/32/72_2.png) [@giuseppe.bilotta](https://gpusph.discourse.group/u/giuseppe.bilotta)\
**Post date:** [November 12, 2024, 7:06am UTC](https://gpusph.discourse.group/t/flag-to-check-splitting/217/2 "2024-11-12T07:06:33Z")

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You get information about the domain splitting in the logs that gets printed in console.  
You can pipe this to disk with something like `./YourTestCase 2>&1 | tee testcase.log` to save the data to file `testcase.log` and then inspect it with information about the particle distribution and the number of bursts needed to transfer data between devices.

For a more “visual” debugging, you can run with a single iteration (`--maxiter 1`) in multi-GPU and the VTK files should now have a `DeviceIndex` scalar field with the device index to which each particle was assigned.

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<div class="post-metadata">

**Author:** ![AlirezaZarei](https://avatars.discourse-cdn.com/v4/letter/a/b5ac83/32.png) [@AlirezaZarei](https://gpusph.discourse.group/u/AlirezaZarei)\
**Post date:** [January 29, 2025, 12:24am UTC](https://gpusph.discourse.group/t/flag-to-check-splitting/217/3 "2025-01-29T00:24:18Z")

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Thanks, Giuseppe!  
It worked! Using ( --maxiter 1) helped me to see the splitting visually in Paraview!  
I appreciate it.

Bests,  
Alireza