# Mixed Poisson problem

**URL:** <https://fenicsproject.discourse.group/t/mixed-poisson-problem/17351>\
**Category:** General\
**Created:** [April 1, 2025, 3:05pm UTC](https://fenicsproject.discourse.group/t/mixed-poisson-problem/17351 "2025-04-01T15:05:06Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [April 1, 2025, 4:33pm UTC](https://fenicsproject.discourse.group/t/mixed-poisson-problem/17351/2 "2025-04-01T16:33:18Z")

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Use another writer than xdmf, as suggested in: [How to make Von Mises Stress look better - #10 by dokken](https://fenicsproject.discourse.group/t/how-to-make-von-mises-stress-look-better/17013/10)

Please search for the error message on the forum before posting  
[https://fenicsproject.discourse.group/search?context=topic&context\_id=17351&q=RuntimeError%3A%20Degree%20of%20output%20Function%20must%20be%20same%20as%20mesh%20degree.%20Maybe%20the%20Function%20needs%20to%20be%20interpolated%3F%20order%3Alatest&skip\_context=true](https://fenicsproject.discourse.group/search?context=topic&context_id=17351&q=RuntimeError%3A%20Degree%20of%20output%20Function%20must%20be%20same%20as%20mesh%20degree.%20Maybe%20the%20Function%20needs%20to%20be%20interpolated%3F%20order%3Alatest&skip_context=true)  
as there are many posts on the same topic.

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