Thanks for the suggestions.
For the moment I will try to use the identity {uu}={u]{u}+0.25[u][u] and
then I'll see what happens.
On Friday, September 9, 2022 at 7:47:29 PM UTC+3 Wolfgang Bangerth wrote:
>
> Abbas,
> I have no specific suggestions to make this easy. The two options I
> would explore are:
> * Build a tensor-valued (discontinuous) finite element, a DoFHandler for
> it, and then interpolate the function u*u onto that finite element field
> -- that is, build a finite element field representation of u*u. You can
> then evaluate that via FEInterfaceValues.
> * Take a look at how FEInterfaceValues computes jump(u) and average(u)
> (namely, by evaluating FEValues objects on both sides of the interface),
> and write code that does something similar for u*u.
>
> The latter approach can be made more general, namely if you wanted to
> evaluate the jump of average of an arbitrary function f(u). I suspect it
> wouldn't be terribly hard to generalize the implementation of jump(u)
> and average(u) to that case, and that might be interesting to others as
> well if it were put into deal.II itself. If you'd like to explore this
> and write a patch, let me know and I'll walk you through how one would
> approach that!
>
> Best
> Wolfgang
>
>
> On 9/9/22 01:08, Abbas wrote:
> > *** Caution: EXTERNAL Sender ***
> >
> > Yes
> >
> > On Friday, September 9, 2022 at 12:06:23 AM UTC+3 Wolfgang Bangerth
> wrote:
> >
> > On 9/8/22 04:40, Abbas wrote:
> > >
> > > I want the average of (uu) which is = u1*u1/2 +u2*u2/2 but I
> > don't know
> > > how to get it.
> >
> > Do I understand right that u1 and u2 are vectors, and when you say
> > u1 * u1
> > you mean the outer product of a vector with itself, forming a tensor?
> >
> > Best
> > W.
> >
> > --
> > ------------------------------------------------------------------------
> >
> > Wolfgang Bangerth email: bang...@colostate.edu
> > www: http://www.math.colostate.edu/~bangerth/
> > <http://www.math.colostate.edu/~bangerth/>
> >
> > --
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> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth email: bang...@colostate.edu
> www: http://www.math.colostate.edu/~bangerth/
>
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