# I need two write the second term of the bilinear form in FreeFem++

**URL:** <https://community.freefem.org/t/i-need-two-write-the-second-term-of-the-bilinear-form-in-freefem/3581>\
**Category:** Feature Request\
**Created:** [November 14, 2024, 3:33am UTC](https://community.freefem.org/t/i-need-two-write-the-second-term-of-the-bilinear-form-in-freefem/3581 "2024-11-14T03:33:33Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Monirul25](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/monirul25/32/3287_2.png) [@Monirul25](https://community.freefem.org/u/Monirul25)\
**Post date:** [November 14, 2024, 3:33am UTC](https://community.freefem.org/t/i-need-two-write-the-second-term-of-the-bilinear-form-in-freefem/3581/1 "2024-11-14T03:33:33Z")

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Can someone help me how to write the second term of the bilinear form??

 ![Help](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/2X/b/bdeb17438802060bca300b397f947e22da11d483.png)  
 ![Screenshot 2024-11-13 165654](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/2X/3/3ad10f6e181b50ea3ab7f7ef25a874b15721dafa.png)

Also, given that theta= 0 on boundary of the domain.

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**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\
**Post date:** [November 21, 2024, 8:15am UTC](https://community.freefem.org/t/i-need-two-write-the-second-term-of-the-bilinear-form-in-freefem/3581/2 "2024-11-21T08:15:04Z")

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The problem is if w is not constant a boundary edge the set \partial E\_{-}^w is a full edge.

other wise you can add term like :

```auto
([w1,w2]'*N < 0) 

```

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<div class="post-metadata">

**Author:** ![Monirul25](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/monirul25/32/3287_2.png) [@Monirul25](https://community.freefem.org/u/Monirul25)\
**Post date:** [November 21, 2024, 10:27am UTC](https://community.freefem.org/t/i-need-two-write-the-second-term-of-the-bilinear-form-in-freefem/3581/3 "2024-11-21T10:27:56Z")

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Dear professor please check if the following FreeFem++ code is correct code of the second term of the bilinear form according to your suggesion:

> Blockquote  
> +intalledges(Th)((abs(N.x_mean(v1old)+N.y_mean(v2old))_jump(v1)jump(vv1))/nTonEdge(nTonEdge-1))  
> +int1d(Th)(abs(N.x_v1old+N.y_v2old)v1vv1)  
> +intalledges(Th)((abs(N.x_mean(v1old)+N.y_mean(v2old))jump(v2)jump(vv2))/nTonEdge(nTonEdge-1))  
> +int1d(Th)(abs(N.xv1old+N.y_v2old)_v2_vv2)

> Blockquote

Here, v is known ,v=(v1old,v2old), z=(v1,v2) is unkown, theta=(vv1,vv2) is test function.