# Can we control the domain decomposition

**URL:** <https://community.freefem.org/t/can-we-control-the-domain-decomposition/4105>\
**Category:** General Discussion\
**Created:** [October 17, 2025, 10:12am UTC](https://community.freefem.org/t/can-we-control-the-domain-decomposition/4105 "2025-10-17T10:12:50Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![zxss](https://avatars.discourse-cdn.com/v4/letter/z/bc8723/32.png) [@zxss](https://community.freefem.org/u/zxss)\
**Post date:** [October 17, 2025, 10:12am UTC](https://community.freefem.org/t/can-we-control-the-domain-decomposition/4105/1 "2025-10-17T10:12:50Z")

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Dear all,

I have a question, that is can we control the domain decomposition by ourselves?

For example, for a fluid-structure interaction(large fluid and small solid), if I have ten processors, I want to allocate one for the whole solid domain and the else 9 for fluid part. Is it possible?

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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [October 17, 2025, 11:24am UTC](https://community.freefem.org/t/can-we-control-the-domain-decomposition/4105/2 "2025-10-17T11:24:53Z")

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Yes, look for `UserPartitioning` in the `examples/hpddm` folder.

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**Author:** ![zxss](https://avatars.discourse-cdn.com/v4/letter/z/bc8723/32.png) [@zxss](https://community.freefem.org/u/zxss)\
**Post date:** [October 17, 2025, 11:46am UTC](https://community.freefem.org/t/can-we-control-the-domain-decomposition/4105/3 "2025-10-17T11:46:42Z")

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Many thanks for your reply. I have another question. I learned from your expert video on Youtube that ‘movemesh‘ cannot be directly used in parallel for distributed meshes because there could be incoherent on the overlapping mesh. Is there a good method to movemesh now? Actually, I have a idea, that is I firstly do a partition of unit to make the displacement function coherent, and then movemesh.

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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [October 17, 2025, 12:10pm UTC](https://community.freefem.org/t/can-we-control-the-domain-decomposition/4105/4 "2025-10-17T12:10:42Z")

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No, you need to centralize your solution, `movemesh` only on a single process, and re-decompose.

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**Author:** ![zxss](https://avatars.discourse-cdn.com/v4/letter/z/bc8723/32.png) [@zxss](https://community.freefem.org/u/zxss)\
**Post date:** [October 17, 2025, 1:24pm UTC](https://community.freefem.org/t/can-we-control-the-domain-decomposition/4105/5 "2025-10-17T13:24:18Z")

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Got it, many thanks! Wow, it could be a challenge to move a fine 3D mesh. It may need enough memory, I think…….