I am adding here an attempt I made. It seems to work but since this was
more intuition rather than full understanding, I do appreciate your
comments.
So, this is what I did: basically, I created two Dirichlet boundary
conditions and two masks, and I applied conditions in sequence, like this:
// Dirichlet bcs
// -------------
PETScWrappers::MPI::Vector tmp (locally_owned_dofs,mpi_communicator);
// Dirichlet bc for displacements
{
std::map<types::global_dof_index,double> boundary_values;
ComponentMask displacements_mask = fe.component_mask (displacements);
VectorTools::interpolate_boundary_values (dof_handler,
0,
IncrementalDirichletBoundaryValues<dim>( TIDM, NRit, GPDofs ),
boundary_values,
displacements_mask);
MatrixTools::apply_boundary_values (boundary_values,
system_matrix,
tmp,
system_rhs,
false);
}
// Dirichlet bc for concentrations
{
std::map<types::global_dof_index,double> boundary_values;
ComponentMask displacements_mask = fe.component_mask (concentration);
VectorTools::interpolate_boundary_values (dof_handler,
0,
IncrementalDirichletBoundaryValuesForConcentration<dim>( TIDM, NRit, GPDofs
),
boundary_values,
displacements_mask);
PETScWrappers::MPI::Vector tmp (locally_owned_dofs,mpi_communicator);
MatrixTools::apply_boundary_values (boundary_values,
system_matrix,
tmp,
system_rhs,
false);
}
incremental_displacement = tmp;
Within the classes IncrementalDirichletBoundaryValuesForConcentration
I have returned something like:
template <int dim>
void
IncrementalDirichletBoundaryValuesForConcentration<dim>::
vector_value (const Point<dim> & p ,
Vector<double> & return_value) const
{
static const unsigned int c_component = dim + 2;
return_value( c_component ) = ... ;
}
Does it make sense?
Thanks
Alberto
Il giorno mercoledì 31 maggio 2017 17:48:13 UTC-4, Alberto Salvadori ha
scritto:
>
> Dear all,
>
> your help is appreciated about how component mask and Dirichlet bc
> application work.
>
> I am implementing a SmallStrainDiffusionMechanicalProblem class, with 4
> fields: displacements, pressure, dilatation, and concentration.
>
> template <int dim>
>
> class SmallStrainDiffusionMechanicalProblem
>
> {
>
> ...
>
>
> // dofs definiton and dofs block enumeration
>
> // dim = displacements dofs
>
> // 1 = p
>
> // 1 = J
>
> // 1 = c ( interstitial concentration )
>
> const unsigned int GPDofs = dim + 3;
>
>
> static const unsigned int first_u_component = 0;
>
> static const unsigned int p_component = dim;
>
> static const unsigned int J_component = dim + 1;
>
> static const unsigned int c_component = dim + 2;
>
>
> enum
>
> {
>
> u_dof = 0, // displacement block ( dim components )
>
> p_dof = 1, // pressure block ( one component )
>
> J_dof = 2, // dilatation block ( one component )
>
> c_dof = 3 // concentration block ( one component )
>
> };
>
>
>
> ...
>
> }
>
>
> In a former implementation that did not include concentration fields, in
> order to impose bc to the vector solution incremental_displacement, I
> have edited some code from the tutorials, like this:
>
>
> const FEValuesExtractors::Vector displacements (first_u_component);
>
> const FEValuesExtractors::Scalar pressure(p_component);
>
> const FEValuesExtractors::Scalar dilatation(J_component);
>
> const FEValuesExtractors::Scalar concentration(c_component);
>
> ......
>
> std::map<types::global_dof_index,double> boundary_values;
>
>
> ComponentMask displacements_mask = fe.component_mask (displacements);
>
> VectorTools::interpolate_boundary_values (dof_handler,
>
> 0,
>
>
> IncrementalDirichletBoundaryValues<dim>( TIDM, NRit, GPDofs ),
>
> boundary_values,
>
> displacements_mask);
>
>
>
> PETScWrappers::MPI::Vector tmp (locally_owned_dofs,mpi_communicator);
>
> MatrixTools::apply_boundary_values (boundary_values,
>
> system_matrix,
>
> tmp,
>
> system_rhs,
>
> false);
>
> incremental_displacement = tmp;
>
> I would now impose Dirichlet bc on both displacements and concentrations
> and assume that the Dirichlet boundary for both fields is the same. Shall I
> therefore change the mask, I assume. Can it be done like this?
>
> ComponentMask displacements_mask = fe.component_mask (displacements,
> concentrations);
>
> or shall two masks be defined or even else?
>
> Many thanks!
> Alberto
>
>
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