# Code for Q1 element for elliptic equation

**URL:** <https://community.freefem.org/t/code-for-q1-element-for-elliptic-equation/2368>\
**Category:** General Discussion\
**Created:** [March 30, 2023, 7:04pm UTC](https://community.freefem.org/t/code-for-q1-element-for-elliptic-equation/2368 "2023-03-30T19:04:30Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ogabic](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/ogabic/32/1616_2.png) [@ogabic](https://community.freefem.org/u/ogabic)\
**Post date:** [March 30, 2023, 7:04pm UTC](https://community.freefem.org/t/code-for-q1-element-for-elliptic-equation/2368/1 "2023-03-30T19:04:30Z")

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Hi all , please I’m looking for a code for the rectangle Q1 finite element method ( rectangle mesh) for the following poisson equation  
e\*dx^2 u + dy^2 u = f with Dirichlet boundary condition on a square (0,1)x(0,1)  
Where e is a positive constant.  
Please help me , I didn’t found any thing about that in the sources of FreeFem++  
Could you help me , thank you very much

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**Author:** ![cmd](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/cmd/32/67_2.png) [@cmd](https://community.freefem.org/u/cmd)\
**Post date:** [March 31, 2023, 6:50am UTC](https://community.freefem.org/t/code-for-q1-element-for-elliptic-equation/2368/2 "2023-03-31T06:50:25Z")

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FreeFEM uses only triangular elements.