# Incorrect convergence rate for "Element\_P4" in 2d

**URL:** <https://community.freefem.org/t/incorrect-convergence-rate-for-element-p4-in-2d/1400>\
**Category:** General Discussion\
**Created:** [December 21, 2021, 7:42pm UTC](https://community.freefem.org/t/incorrect-convergence-rate-for-element-p4-in-2d/1400 "2021-12-21T19:42:56Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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:** [December 21, 2021, 8:53pm UTC](https://community.freefem.org/t/incorrect-convergence-rate-for-element-p4-in-2d/1400/2 "2021-12-21T20:53:35Z")

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You need to use an appropriate `qforder`, see [Quadrature formulae](https://doc.freefem.org/references/quadrature-formulae.html#qf9pt) or this similar topic [Default quadrature rule](https://community.freefem.org/t/default-quadrature-rule/415).

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_[View the full topic](https://community.freefem.org/t/incorrect-convergence-rate-for-element-p4-in-2d/1400)._