# Partial periodic boundary condition erroe

**URL:** <https://community.freefem.org/t/partial-periodic-boundary-condition-erroe/465>\
**Category:** General Discussion\
**Created:** [June 11, 2020, 8:50am UTC](https://community.freefem.org/t/partial-periodic-boundary-condition-erroe/465 "2020-06-11T08:50:04Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![wangicewing](https://avatars.discourse-cdn.com/v4/letter/w/ac91a4/32.png) [@wangicewing](https://community.freefem.org/u/wangicewing)\
**Post date:** [June 11, 2020, 8:50am UTC](https://community.freefem.org/t/partial-periodic-boundary-condition-erroe/465/1 "2020-06-11T08:50:04Z")

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- Square mesh : nb vertices =3321 , nb triangles = 6400 , nb boundary edges 240  
Problem build of FEspace (2d) (may be : due to periodic Boundary condition missing ) FH  
The number of DF must be 55120 and it is 55485  
current line = 98  
Assertion fail : (snbdf == NbOfDF)  
line :1057, in file …/femlib/FESpace.cpp  
Assertion fail : (snbdf == NbOfDF)  
line :1057, in file …/femlib/FESpace.cpp  
err code 5 , mpirank 0

This is freefem error message.

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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:** [June 11, 2020, 8:58am UTC](https://community.freefem.org/t/partial-periodic-boundary-condition-erroe/465/2 "2020-06-11T08:58:39Z")

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If we can’t reproduce the problem on our machines, we sadly can’t help you.  
Please post a [MWE](https://en.wikipedia.org/wiki/Minimal_working_example) (.mesh, .edp, and what not).