# 3D analogue of intalledges etc

**URL:** <https://community.freefem.org/t/3d-analogue-of-intalledges-etc/78>\
**Category:** Feature Request\
**Created:** [June 20, 2019, 6:51am UTC](https://community.freefem.org/t/3d-analogue-of-intalledges-etc/78 "2019-06-20T06:51:11Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![alozinski](https://avatars.discourse-cdn.com/v4/letter/a/b5ac83/32.png) [@alozinski](https://community.freefem.org/u/alozinski)\
**Post date:** [June 20, 2019, 6:51am UTC](https://community.freefem.org/t/3d-analogue-of-intalledges-etc/78/1 "2019-06-20T06:51:11Z")

</div>

Hi,  
I’m trying to explore some stabilized FE schemes involving the integrals of gradient jumps over the mesh facets. This works fine in 2D with intalledges. I know that the 3D analogue intallfaces exists but it does not seem to work. Here is the minimal example :

load “msh3”  
int n=10;  
mesh3 Th = cube(n, n, n);  
fespace Vh(Th,P1);  
Vh u,v;  
u=1;  
cout \<\<intallfaces(Th)(u)\<\<endl;

This gives the obviously wrong answer 0 (in version 4.2.1)

If I continue with

macro dN(u) (dx(u)\*N.x+dy(u)\*N.y+dz(u)\*N.z) //  
solve test(u,v)=intallfaces(Th)(jump(dN(u))\*jump(dN(v)) )  
-int3d(Th)(v);

then it gives  
Assertion fail : (0)  
line :202, in file problem.cpp

Could you please correct this issue?  
Moreover, it would be useful to create a 3D analogue of nTonEdge and to check if jump and mean work properly in 3D.

Thanks in advance,  
Alexei

---

<div class="post-metadata">

**Author:** ![munch](https://avatars.discourse-cdn.com/v4/letter/m/a4c791/32.png) [@munch](https://community.freefem.org/u/munch)\
**Post date:** [July 11, 2019, 7:24am UTC](https://community.freefem.org/t/3d-analogue-of-intalledges-etc/78/2 "2019-07-11T07:24:32Z")

</div>

Dear All,

I share the same request than Alexei; everything is fine in 2d with intalledges, but the command intallfaces(jump(dn(u))\*jump(dn(v))) with v,u in P^2 produces a “Segmentation fault: 11”.

Regards, Arnaud

---

<div class="post-metadata">

**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:** [February 5, 2020, 7:14am UTC](https://community.freefem.org/t/3d-analogue-of-intalledges-etc/78/3 "2020-02-05T07:14:39Z")

</div>

Yes, I know, the Discontinuous Galerkin is not coded in 3d, so all this stuff given wrong result.

Sorry, Frederic Hecht