# DG for incompressible NSE

In the above trilinear form we need to use the convect(.) operator for first term but for other terms how we can write them in freefem.

You have an example of use of discontinuous Galerkin for the Laplace problem at
https://www.um.es/freefem/ff++/pmwiki.php?n=Main.DiscontinuousGalerkin
You will see the use of mean() and jump()

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Is it possible to modify the content of `mean()` and `jump()`? I would like to use a weighted DG method where the `mean` and `jump` functions are not defined with the standard definitions.

Thank you, N.

I would say that it is not possible to modify them, but maybe somebody has some ideas to do that (take a combination of mean and jump in order to get a weighted mean ?). It depends strongly on the precise formula you would like to implementâ€¦

Hello Sir, I am trying to apply DG for pressure correction scheme of navier stokes equation.
In my code the bilinear form,:-
problem U ([uu1,uu2], [v1,v2])= int2d(Th) (uu1v1+uu2 v2) + int2d(Th) (phidt (dx(v1) + dy(v2))) // velocity Correction
-intalledges(Th) (dt * mean(phi) * (jump(v1)*N.x+jump(v2)N.y)/nTonEdge)
-int2d(Th)(u1 * v1+u2 * v2)
;
isnâ€™t working. Here phi is a known value, calculated from a previous bilinear form. I think the problem occurs when i am trying to integrate the product â€śmean(phi)
( jump(v1) * N.x + jump(v2) * N.y)â€ť.
So is there any other way of doing this integration or the problem is in somewhere else.