On Sun, Mar 14, 2010 at 11:48:21PM -0000, Murtazo Nazarov wrote: > Question #103034 on DOLFIN changed: > https://answers.launchpad.net/dolfin/+question/103034 > > Murtazo Nazarov posted a new comment: > Murtazo Nazarov wrote: > > Your question #103034 on DOLFIN changed: > > https://answers.launchpad.net/dolfin/+question/103034 > > > > Status: Answered => Open > > > > You are still having a problem: > > Anders Logg wrote: > > > >> Question #103034 on DOLFIN changed: > >> https://answers.launchpad.net/dolfin/+question/103034 > >> > >> Status: Open => Answered > >> > >> Anders Logg proposed the following answer: > >> On Wed, Mar 03, 2010 at 02:36:59AM -0000, Murtazo Nazarov wrote: > >> > >> > >>> New question #103034 on DOLFIN: > >>> https://answers.launchpad.net/dolfin/+question/103034 > >>> > >>> Hi, > >>> > >>> I am wondering how to compute an L1-norm, and L_inf norm of a functional > >>> on the cell. For instance how to compute > >>> > >>> 1. ||\div(Pu)||_{L_\infty} ? > >>> > >>> > >> Try projecting div(Pu) onto piecewise constants and then pick the > >> largest absolute value in the vector. > >> > >> > >> > > > > I need L_inf norm on the cell. With this way, doesn't give the L_inf for > > the entire domain? > > > > murtazo > > > > > > Instead of projecting div(Pu) onto piecewise constants, I projected it > into dG(1), with this way I get three values on each cell, which I can > then pick up the largest of them. That gives me then L_inf_K, where K is > a cell. Now, I cannot figured out how is the numbering done for the > dG(1) elements. > > If N is a total number of cells, then my projected vector Pdg has 3*N > elements. How can I pick up elements of Pdg in the cell K? > > Thanks, > murtazo
Why do you use DG(1) instead of DG(0)? If you use DG(0), the numbering
is easier.
--
Anders
> >>> 2. ||\div(Pu)||_{L_1} ?
> >>>
> >>>
> >> Try
> >>
> >> M = abs(div(Pu))*dx
> >>
> >>
> >>
> >>
> >>
> >>> where u is velocity (vector) and P is pressure (scalar). L2 norm is
> >>> obvious to do.
> >>>
> >>> I use C++ interface
> >>>
> >>>
> >>>
> >>
> >
> >
>
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