dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Wed, Dec 17, 2008 at 11:42:47PM +0100, Johan Hake wrote:
> On Wednesday 17 December 2008 22:57:48 Anders Logg wrote:
> > On Wed, Dec 17, 2008 at 10:53:32PM +0100, 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:   5406:bc43cc830c11058dcabf239a5a7f878bb860fabb
> > > tag:         tip
> > > user:        Anders Logg <logg@xxxxxxxxx>
> > > date:        Wed Dec 17 22:53:27 2008 +0100
> > > files:       TODO demo/la/eigensolver/python/demo.py
> > > demo/pde/optimization/python/demo.py description:
> > > Fix remaining unchecked demos. Some demos still broken:
> > >
> > >   EE demo/pde/nonlinear-poisson/python/demo.py
> > >   EE demo/pde/poisson1D/python/demo.py                    viper problem
> > > with 1D EE demo/pde/waveguide/python/demo.py                    results
> > > in C++ and Python differ EE
> > > demo/pde/dg/advection_diffusion/python/demo.py
> > >   EE demo/nls/nonlinearpoisson/python/demo.py
> > >   EE demo/mesh/partitioning/python/demo.py
> > >   EE demo/mesh/intersection/python/demo.py                strange
> > > transformation EE demo/ode/aliev-panfilov/python/demo.py
> > > EE demo/ode/lorenz/python/demo.py
> >
> > We may ignore the ODE demos here. Some work is needed to get the ODE
> > solvers to function from Python but they have only worked in part
> > before so it's not very important now.
> >
> > The following demos remain:
> >
> >    demo/pde/nonlinear-poisson/python/demo.py            ?
> >    demo/pde/poisson1D/python/demo.py                    viper problem with
> > 1D demo/pde/waveguide/python/demo.py                    results in C++ and
> > Python differ 
> >    demo/pde/dg/advection_diffusion/python/demo.py       ? 
> 
> This demo is somewhat depricated as it stands now. I added it based on the 
> previous c++ demo. Since then has the c++ demo changed, to be more simple, 
> but including the builtin OutflowFacet special function. This is not included 
> in the python interface.
> 
> To get it up and running in python we need to add OutflowFacet to the python 
> interface. This should be doable, and quite straightforward with the new 
> function interface. Please correct me:
> 
> class OutflowFacet(ffc.Function,cpp.OutflowFacet):
>     def __init__(self, vec_field):
>         appropriate check on vec_field
>         mesh = vec_field.function_space().mesh()
> 
>         # Define the OutflowFacet form
>         n = FacetNormal(mesh)
>         a = ffc.dot(vec_field,n)*ffc.ds
>         self._dolfin_form = Form(a)
> 
>         domain  = dim2domain[mesh.topology().dim()]
>         self._element = ffc.FiniteElement("Discontinuous Lagrange", domain, 0)
> 
>         ffc.Function.__init__(self, self._element)
>         cpp.OutflowFacet(self, self._dolfin_form)
> 
> It is a bastard wrt being a full fledged dolfin.Function, it does not define 
> its own function space. I do not know if this would be a problem as the c++ 
> counterpart neither initiate its base class with a functionspace. 
> 
> Once this function is in place the rest should be quite straight forward.
> 
> Johan

It looks strange to me, and so does the C++ version (that a Function
needs to be initialized with a form).

How about just evaluating the function at the midpoint of the facet
and computing the inner product with the facet normal?

-- 
Anders

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