Hello, I am relatively new to deal.ii. I wonder if I can deal with
conflicting constraints without using
VectorTools::interpolate_boundary_values()
<https://www.dealii.org/8.4.1/doxygen/deal.II/namespaceVectorTools.html#af6f700f193e9d5b52e9efe55e9b872d5>.
The explanation here
(https://www.dealii.org/8.4.1/doxygen/deal.II/group__constraints.html)
only gives the cases using it. The reason I don't want to use it is that I
need to impose Dirichlet boundary conditions at points (at specific nodes).
I do not believe VectorTools::interpolate_boundary_values()
<https://www.dealii.org/8.4.1/doxygen/deal.II/namespaceVectorTools.html#af6f700f193e9d5b52e9efe55e9b872d5>
can
handle such a boundary condition.
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. However,
for handling conflict between hanging node and boundary condition with
ConstraintMatrix, just doing something like:
typename DoFHandler<dim>::active_cell_iterator cell =
dof_handler.begin_active(),
endc =
dof_handler.end();
for (; cell!=endc; ++cell)
{
for (unsigned int vert = 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:
Exception on processing:
--------------------------------------------------------
An error occurred in line <828> of file
</home/shlee/Software/dealii-8.1/include/deal.II/lac/solver_gmres.h> in
function
void dealii::SolverGMRES<VECTOR>::solve(const MATRIX&, VECTOR&, const
VECTOR&, const PRECONDITIONER&) [with MATRIX =
dealii::LinearAlgebraTrilinos::MPI::BlockSparseMatrix, PRECONDITIONER =
BlockDiagonalPreconditioner<dealii::TrilinosWrappers::PreconditionAMG,
dealii::TrilinosWrappers::PreconditionAMG>, VECTOR =
dealii::TrilinosWrappers::MPI::BlockVector]
The violated condition was:
false
The name and call sequence of the exception was:
SolverControl::NoConvergence (this->control().last_step(),
this->control().last_value())
Additional Information:
Iterative method reported convergence failure in step 1000 with residual
1.2908e-13
The simulation result looks reasonable until it gives the error, and so I
think I correctly assigned the boundary condition at
the points. The problem might be conflicting constraints are not handled
appropriately in ConstraintMatrix. I hope my explanation is clear. It would
be great if you could replay my question.
Regards.
Sogo
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