I assign such a boundary condition at points by giving boundary values
to std::map<unsigned int,double> boundary_values directly, and it looks
working well.
Yes, this is the correct approach.
However, for handling conflict between hanging node and
boundary condition with ConstraintMatrix, just doing something like:
typenameDoFHandler<dim>::active_cell_iterator cell = dof_handler.begin_active(),
endc =
dof_handler.end();
for(; cell!=endc; ++cell)
{
for(unsignedintvert = 0; vert < GeometryInfo<dim>::vertices_per_cell;
vert++)
{
if("certain condition")
{
constraints_update.add_line(cell2->vertex_dof_index(vert,I));
}
}
}
(Here constraints_update is an object of ConstraintMatrix).
does not seem working because the solver eventually gives the error:
[...]
Well, that means that your matrix is probably not invertible (although the
residual does get pretty small -- are you sure you don't just need more
iterations?). This *may* be because of your constraints, but it may also be
because of any number of other reasons. Have you tried this on a small
problem, say a 2x2 or 3x3 mesh, to make sure it really is because of the
constraints? For small problems, you can often figure out on a piece of paper
what the matrix should be, and compare with what you get from your program.
Best
W.
--
------------------------------------------------------------------------
Wolfgang Bangerth email: bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/
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