dolfin team mailing list archive

[Patrick Riesen <priesen@xxxxxxxxxxxxxxx>]

> Is it required to use pointwise eval of your subdomain.

i neither think that it's required, but i was testing all possible 
stuff. in fact, my code does work on some subdomains, but for others 
(e.g. where i have to do a coordinate transformation) i have some 
problem that some points are evaluated correctly but just come wrong in 
the 2D BC inflow condition. like as if some dofs got missed, the inflow 
profile looks like a parabolic "saw"...


  This is
> usually better for when you want to mark something that won't be
> counted as the boundary or a small number of points that are not in
> the topological search (like lower dimension than a facet).  If you
> are marking a mesh function then this should be all that is needed to
> tell what points to call your BC functions on.  When you define the
> function for applying the BC, it will still give you a point that you
> can eval from your other mesh.
>
> -- Andy
>
> On Fri, Mar 26, 2010 at 5:33 AM, Patrick Riesen <priesen@xxxxxxxxxxxxxxx> wrote:
> > hello,
> >
> > i'm under way of creating in-/outflow bc conditions by transferring a
> > discrete 1D flow profile function onto a boundary subdomain of a 2D mesh. I
> > marked the subdomain by a meshfunction and use an expression in which i
> > evaluate the bcs values by extracting them from the 1D discrete solution as
> >
> > BCInFlowProfile::eval (Array<double>& values, const Array<double>& x) const
> > {
> >  [....]
> >  velocity1Dprofile.eval(values, x_eval);
> >  [....]
> >
> > }
> > i want to use "pointwise" method for applying the bcs, so that the
> > velocities evaluated and specified on the vertices, but i get
> >
> > dolfin/fem/DirichletBC.cpp:635: void
> > dolfin::DirichletBC::compute_bc_pointwise(std::map<unsigned int, double,
> > std::less<unsigned int>, std::allocator<std::pair<const unsigned int,
> > double> > >&, dolfin::BoundaryCondition::LocalData&) const: Assertion
> > `user_sub_domain' failed.
> >
> >
> > is using DirichletBC "pointwise" with a meshfunction and a subdomain id not
> > possible?
> >
> > regards,
> > patrick
> >
> >
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