dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Garth N. Wells wrote:
> Anders Logg wrote:
> > On Mon, Dec 22, 2008 at 10:31:30PM +0000, Garth N. Wells wrote:
> > > Anders Logg wrote:
> > > > On Mon, Dec 22, 2008 at 05:52:01PM +0100, Anders Logg wrote:
> > > > > On Mon, Dec 22, 2008 at 03:56:10PM +0000, Garth N. Wells wrote:
> > > > > > DOLFIN wrote:
> > > > > > > One or more new changesets pushed to the primary dolfin repository.
> > > > > > > A short summary of the last three changesets is included below.
> > > > > > >
> > > > > > > changeset:   5428:5ee944b2216752dd3078f0906c9500837a65097a
> > > > > > > tag:         tip
> > > > > > > user:        "Johan Hake <hake@xxxxxxxxx>"
> > > > > > > date:        Sat Dec 20 22:59:46 2008 +0100
> > > > > > > files:       demo/pde/dg/advection-diffusion/cpp/main.cpp demo/pde/dg/advection-diffusion/python/demo.py dolfin/function/SpecialFunctions.cpp dolfin/function/SpecialFunctions.h site-packages/dolfin/specialfunctions.py
> > > > > > > description:
> > > > > > > Work on getting dg advection-diffusion demo to work in python
> > > > > > >  - Changed name of OutFlowFacet function to Is...
> > > > > > >  - IsOutFlowFacet is instantiated using a FunctionSpace and a field funtion
> > > > > > >  - the evaluation of IsOutFlowFacet is done by evaluating the field in the midpoint
> > > > > > >    of the facet
> > > > > > >  - Does not work properly yet.
> > > > > > What's the status of this? Is anyone working on it and what needs to be 
> > > > > > done?
> > > > > >
> > > > > > Garth
> > > > > We need to move part of FunctionSpace::eval() to another function so
> > > > > we can reuse it from IsOutFlowFacet::eval(). I'll have a look as soon
> > > > > as I get a chance, maybe even tonight.
> > > > >
> > > > > Once this is in place, the two advection-diffusion demos need to be
> > > > > looked at, and then the two nonlinear demos.
> > > > I've made the changes to Function, FunctionSpace, and IsOutflowFacet.
> > > The C++ and Python results look different.
> > >
> > > Garth
> > Yes, I noticed. Do we know if any of them is correct?
>
> The C++ one looks good. There is something odd happening on the bottom 
> boundary in the Python demo, and to a lesser extent on the left boundary 
> (both outflow boundaries). There could be a problem in computing outflow 
> facets on the boundaries.

I removed the *ds (exterior facet integral) from the form in the Python 
demo and the result is the same as it was with the *ds term, which seems 
to indicate that the boundary facets are indeed the problem.

Garth


> Garth
>
> > If so, it will help debugging. Once the bug is found, we can use the
> > built-in IsOutflowFacet in main.cpp.
> >
> >
> >
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