ufl team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Apr 07, 2009 at 05:19:42PM +0200, Martin Sandve Alnæs wrote:
> On Tue, Apr 7, 2009 at 5:17 PM, Anders Logg <logg@xxxxxxxxx> wrote:
> > On Tue, Apr 07, 2009 at 02:48:44PM +0200, UFL wrote:
> >> One or more new changesets pushed to the primary ufl repository.
> >> A short summary of the last three changesets is included below.
> >>
> >> changeset:   811:b96d2bbe8284a7255ca510c2fbb35b1445f85a11
> >> tag:         tip
> >> user:        "Martin Sandve Alnæs <martinal@xxxxxxxxx>"
> >> date:        Tue Apr 07 14:50:30 2009 +0200
> >> files:       doc/manual/chapters/formlanguage.tex ufl/operators.py
> >> description:
> >> Added support for this syntax:
> >>
> >> x = cell.x
> >> Df = diff(f, x)
> >>
> >> Note that
> >>   diff(f, x) == grad(f).T
> >> because of the way diff is defined.
> >> Thus diff(f,x) is the same as the FFC grad.
> >> If we want to change this, it touches a lot
> >> of places in AD code, so that won't happen now.
> >
> > How should the Navier-Stokes convective term be expressed in UFL?
> >
> > I guess one needs to write
> >
> >  grad(u).T*u
> >
> > ?
> 
> Like you write it on paper:
> 
> w . grad u = dot(w, grad(u))
> 
> And:
> 
> w . grad u . v = dot(dot(w, grad(u)), v)

Yes, but does 

  grad(u).T*u

also work?

-- 
Anders

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