Reference documentation for deal.II version 9.3.0

#include <deal.II/multigrid/mg_transfer_matrix_free.h>
Public Member Functions  
MGTransferMatrixFree ()  
MGTransferMatrixFree (const MGConstrainedDoFs &mg_constrained_dofs)  
virtual  ~MGTransferMatrixFree () override=default 
void  initialize_constraints (const MGConstrainedDoFs &mg_constrained_dofs) 
void  clear () 
void  build (const DoFHandler< dim, dim > &dof_handler, const std::vector< std::shared_ptr< const Utilities::MPI::Partitioner >> &external_partitioners=std::vector< std::shared_ptr< const Utilities::MPI::Partitioner >>()) 
virtual void  prolongate (const unsigned int to_level, LinearAlgebra::distributed::Vector< Number > &dst, const LinearAlgebra::distributed::Vector< Number > &src) const override 
virtual void  prolongate_and_add (const unsigned int to_level, LinearAlgebra::distributed::Vector< Number > &dst, const LinearAlgebra::distributed::Vector< Number > &src) const override 
virtual void  restrict_and_add (const unsigned int from_level, LinearAlgebra::distributed::Vector< Number > &dst, const LinearAlgebra::distributed::Vector< Number > &src) const override 
template<typename Number2 , int spacedim>  
void  interpolate_to_mg (const DoFHandler< dim, spacedim > &dof_handler, MGLevelObject< LinearAlgebra::distributed::Vector< Number >> &dst, const LinearAlgebra::distributed::Vector< Number2 > &src) const 
std::size_t  memory_consumption () const 
template<int dim, typename Number2 , int spacedim>  
void  copy_to_mg (const DoFHandler< dim, spacedim > &dof_handler, MGLevelObject< LinearAlgebra::distributed::Vector< Number >> &dst, const LinearAlgebra::distributed::Vector< Number2 > &src) const 
template<int dim, typename Number2 , int spacedim>  
void  copy_from_mg (const DoFHandler< dim, spacedim > &dof_handler, LinearAlgebra::distributed::Vector< Number2 > &dst, const MGLevelObject< LinearAlgebra::distributed::Vector< Number >> &src) const 
template<int dim, typename Number2 , int spacedim>  
void  copy_from_mg_add (const DoFHandler< dim, spacedim > &dof_handler, LinearAlgebra::distributed::Vector< Number2 > &dst, const MGLevelObject< LinearAlgebra::distributed::Vector< Number >> &src) const 
void  set_component_to_block_map (const std::vector< unsigned int > &map) 
void  print_indices (std::ostream &os) const 
template<class Archive >  
void  serialize (Archive &ar, const unsigned int version) 
Subscriptor functionality  
Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.  
void  subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const 
void  unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const 
unsigned int  n_subscriptions () const 
template<typename StreamType >  
void  list_subscribers (StreamType &stream) const 
void  list_subscribers () const 
Static Public Member Functions  
static ::ExceptionBase &  ExcNoProlongation () 
static ::ExceptionBase &  ExcInUse (int arg1, std::string arg2, std::string arg3) 
static ::ExceptionBase &  ExcNoSubscriber (std::string arg1, std::string arg2) 
Protected Member Functions  
template<int dim, typename Number2 , int spacedim>  
void  copy_to_mg (const DoFHandler< dim, spacedim > &dof_handler, MGLevelObject< LinearAlgebra::distributed::Vector< Number >> &dst, const LinearAlgebra::distributed::Vector< Number2 > &src, const bool solution_transfer) const 
template<int dim, int spacedim>  
void  fill_and_communicate_copy_indices (const DoFHandler< dim, spacedim > &dof_handler) 
Private Member Functions  
template<int degree>  
void  do_prolongate_add (const unsigned int to_level, LinearAlgebra::distributed::Vector< Number > &dst, const LinearAlgebra::distributed::Vector< Number > &src) const 
template<int degree>  
void  do_restrict_add (const unsigned int from_level, LinearAlgebra::distributed::Vector< Number > &dst, const LinearAlgebra::distributed::Vector< Number > &src) const 
Private Attributes  
unsigned int  fe_degree 
bool  element_is_continuous 
unsigned int  n_components 
unsigned int  n_child_cell_dofs 
std::vector< std::vector< unsigned int > >  level_dof_indices 
std::vector< std::vector< std::pair< unsigned int, unsigned int > > >  parent_child_connect 
std::vector< unsigned int >  n_owned_level_cells 
AlignedVector< VectorizedArray< Number > >  prolongation_matrix_1d 
AlignedVector< VectorizedArray< Number > >  evaluation_data 
std::vector< AlignedVector< VectorizedArray< Number > > >  weights_on_refined 
std::vector< std::vector< std::vector< unsigned short > > >  dirichlet_indices 
MGLevelObject< std::shared_ptr< const Utilities::MPI::Partitioner > >  vector_partitioners 
Implementation of the MGTransferBase interface for which the transfer operations is implemented in a matrixfree way based on the interpolation matrices of the underlying finite element. This requires considerably less memory than MGTransferPrebuilt and can also be considerably faster than that variant.
This class currently only works for tensorproduct finite elements based on FE_Q and FE_DGQ elements, including systems involving multiple components of one of these elements. Systems with different elements or other elements are currently not implemented.
Definition at line 54 of file mg_transfer_matrix_free.h.
MGTransferMatrixFree< dim, Number >::MGTransferMatrixFree  (  ) 
Constructor without constraint matrices. Use this constructor only with discontinuous finite elements or with no local refinement.
Definition at line 43 of file mg_transfer_matrix_free.cc.
MGTransferMatrixFree< dim, Number >::MGTransferMatrixFree  (  const MGConstrainedDoFs &  mg_constrained_dofs  ) 
Constructor with constraints. Equivalent to the default constructor followed by initialize_constraints().
Definition at line 53 of file mg_transfer_matrix_free.cc.

overridevirtualdefault 
Destructor.
void MGTransferMatrixFree< dim, Number >::initialize_constraints  (  const MGConstrainedDoFs &  mg_constrained_dofs  ) 
Initialize the constraints to be used in build().
Definition at line 67 of file mg_transfer_matrix_free.cc.
void MGTransferMatrixFree< dim, Number >::clear  (  ) 
Reset the object to the state it had right after the default constructor.
Definition at line 77 of file mg_transfer_matrix_free.cc.
void MGTransferMatrixFree< dim, Number >::build  (  const DoFHandler< dim, dim > &  dof_handler, 
const std::vector< std::shared_ptr< const Utilities::MPI::Partitioner >> &  external_partitioners = std::vector<std::shared_ptr<const Utilities::MPI::Partitioner>>() 

) 
Actually build the information for the prolongation for each level.
The optional second argument of external partitioners allows the user to suggest vector partitioning on the levels. In case the partitioners are found to contain all ghost unknowns that are visited through the transfer, the given partitioners are chosen. This ensures compatibility of vectors during prolongate and restrict with external partitioners as given by the user, which in turn saves some copy operations. However, in case there are unknowns missing – and this is typically the case at some point during hcoarsening since processors will need to drop out and thus children's unknowns on some processor will be needed as ghosts to a parent cell on another processor – the provided external partitioners are ignored and internal variants are used instead.
Definition at line 97 of file mg_transfer_matrix_free.cc.

overridevirtual 
Prolongate a vector from level to_level1
to level to_level
using the embedding matrices of the underlying finite element. The previous content of dst
is overwritten.
to_level  The index of the level to prolongate to, which is the level of dst . 
src  is a vector with as many elements as there are degrees of freedom on the coarser level involved. 
dst  has as many elements as there are degrees of freedom on the finer level. 
Implements MGTransferBase< LinearAlgebra::distributed::Vector< Number > >.
Definition at line 183 of file mg_transfer_matrix_free.cc.

overridevirtual 
Prolongate a vector from level to_level1
to level to_level
, summing into the previous content of dst
.
Reimplemented from MGTransferBase< LinearAlgebra::distributed::Vector< Number > >.
Definition at line 196 of file mg_transfer_matrix_free.cc.

overridevirtual 
Restrict a vector from level from_level
to level from_level1
using the transpose operation of the prolongate() method. If the region covered by cells on level from_level
is smaller than that of level from_level1
(local refinement), then some degrees of freedom in dst
are active and will not be altered. For the other degrees of freedom, the result of the restriction is added.
from_level  The index of the level to restrict from, which is the level of src . 
src  is a vector with as many elements as there are degrees of freedom on the finer level involved. 
dst  has as many elements as there are degrees of freedom on the coarser level. 
Implements MGTransferBase< LinearAlgebra::distributed::Vector< Number > >.
Definition at line 275 of file mg_transfer_matrix_free.cc.
void MGTransferMatrixFree< dim, Number >::interpolate_to_mg  (  const DoFHandler< dim, spacedim > &  dof_handler, 
MGLevelObject< LinearAlgebra::distributed::Vector< Number >> &  dst,  
const LinearAlgebra::distributed::Vector< Number2 > &  src  
)  const 
Interpolate finemesh field src
to each multigrid level in dof_handler
and store the result in dst
. This function is different from restriction, where a weighted residual is transferred to a coarser level (transposition of prolongation matrix).
The argument dst
has to be initialized with the correct size according to the number of levels of the triangulation.
If an inner vector of dst
is empty or has incorrect locally owned size, it will be resized to locally relevant degrees of freedom on each level.
The use of this function is demonstrated in step66.
std::size_t MGTransferMatrixFree< dim, Number >::memory_consumption  (  )  const 
Memory used by this object.
Definition at line 665 of file mg_transfer_matrix_free.cc.

private 
Perform the prolongation operation.
Definition at line 389 of file mg_transfer_matrix_free.cc.

private 
Performs the restriction operation.
Definition at line 534 of file mg_transfer_matrix_free.cc.

inherited 
Transfer from a vector on the global grid to vectors defined on each of the levels separately for the active degrees of freedom. In particular, for a globally refined mesh only the finest level in dst
is filled as a plain copy of src
. All the other level objects are left untouched.

protectedinherited 
Internal function to perform transfer of residuals or solutions basesd on the flag solution_transfer
.

inherited 
Transfer from multilevel vector to normal vector.
Copies data from active portions of an MGVector into the respective positions of a Vector<number>
. In order to keep the result consistent, constrained degrees of freedom are set to zero.

inherited 
Add a multilevel vector to a normal vector.
Works as the previous function, but probably not for continuous elements.

inherited 
If this object operates on BlockVector objects, we need to describe how the individual vector components are mapped to the blocks of a vector. For example, for a Stokes system, we have dim+1 vector components for velocity and pressure, but we may want to use block vectors with only two blocks for all velocities in one block, and the pressure variables in the other.
By default, if this function is not called, block vectors have as many blocks as the finite element has vector components. However, this can be changed by calling this function with an array that describes how vector components are to be grouped into blocks. The meaning of the argument is the same as the one given to the DoFTools::count_dofs_per_component function.

inherited 
Print the copy index fields for debugging purposes.
Definition at line 399 of file mg_level_global_transfer.cc.

protectedinherited 
Internal function to fill
copy_indices*. Called by derived classes.
Definition at line 285 of file mg_level_global_transfer.cc.

inherited 
Subscribes a user of the object by storing the pointer validity
. The subscriber may be identified by text supplied as identifier
.
Definition at line 136 of file subscriptor.cc.

inherited 
Unsubscribes a user from the object.
identifier
and the validity
pointer must be the same as the one supplied to subscribe(). Definition at line 156 of file subscriptor.cc.

inlineinherited 
Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.
Definition at line 301 of file subscriptor.h.

inlineinherited 
List the subscribers to the input stream
.
Definition at line 318 of file subscriptor.h.

inherited 
List the subscribers to deallog
.
Definition at line 204 of file subscriptor.cc.

inlineinherited 
Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.
This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.
Definition at line 310 of file subscriptor.h.

private 
A variable storing the degree of the finite element contained in the DoFHandler passed to build(). The selection of the computational kernel is based on this number.
Definition at line 196 of file mg_transfer_matrix_free.h.

private 
A variable storing whether the element is continuous and there is a joint degree of freedom in the center of the 1D line.
Definition at line 202 of file mg_transfer_matrix_free.h.

private 
A variable storing the number of components in the finite element contained in the DoFHandler passed to build().
Definition at line 208 of file mg_transfer_matrix_free.h.

private 
A variable storing the number of degrees of freedom on all child cells. It is 2^{dim}*fe.n_dofs_per_cell()
for DG elements and somewhat less for continuous elements.
Definition at line 215 of file mg_transfer_matrix_free.h.

private 
This variable holds the indices for cells on a given level, extracted from DoFHandler for fast access. All DoF indices on a given level are stored as a plain array (since this class assumes constant DoFs per cell). To index into this array, use the cell number times dofs_per_cell.
This array first is arranged such that all locally owned level cells come first (found in the variable n_owned_level_cells) and then other cells necessary for the transfer to the next level.
Definition at line 227 of file mg_transfer_matrix_free.h.

private 
A variable storing the connectivity from parent to child cell numbers for each level.
Definition at line 234 of file mg_transfer_matrix_free.h.

private 
A variable storing the number of cells owned on a given process (sets the bounds for the worker loops) for each level.
Definition at line 240 of file mg_transfer_matrix_free.h.

private 
This variable holds the onedimensional embedding (prolongation) matrix from mother element to all the children.
Definition at line 246 of file mg_transfer_matrix_free.h.

mutableprivate 
This variable holds the temporary values for the tensor evaluation
Definition at line 251 of file mg_transfer_matrix_free.h.

private 
For continuous elements, restriction is not additive and we need to weight the result at the end of prolongation (and at the start of restriction) by the valence of the degrees of freedom, i.e., on how many elements they appear. We store the data in vectorized form to allow for cheap access. Moreover, we utilize the fact that we only need to store 3^{dim}
indices.
Data is organized in terms of each level (outer vector) and the cells on each level (inner vector).
Definition at line 264 of file mg_transfer_matrix_free.h.

private 
A variable storing the local indices of Dirichlet boundary conditions on cells for all levels (outer index), the cells within the levels (second index), and the indices on the cell (inner index).
Definition at line 271 of file mg_transfer_matrix_free.h.

private 
A vector that holds shared pointers to the partitioners of the transfer. These partitioners might be shared with what was passed in from the outside through build() or be shared with the level vectors inherited from MGLevelGlobalTransfer.
Definition at line 280 of file mg_transfer_matrix_free.h.

protectedinherited 
Sizes of the multilevel vectors.
Definition at line 513 of file mg_transfer.h.

protectedinherited 
Mapping for the copy_to_mg() and copy_from_mg() functions. Here only index pairs locally owned is stored.
The data is organized as follows: one table per level. This table has two rows. The first row contains the global index, the second one the level index.
Definition at line 523 of file mg_transfer.h.

protectedinherited 
Same as above, but used to transfer solution vectors.
Definition at line 528 of file mg_transfer.h.

protectedinherited 
Additional degrees of freedom for the copy_to_mg() function. These are the ones where the global degree of freedom is locally owned and the level degree of freedom is not.
Organization of the data is like for copy_indices
.
Definition at line 537 of file mg_transfer.h.

protectedinherited 
Same as above, but used to transfer solution vectors.
Definition at line 542 of file mg_transfer.h.

protectedinherited 
Additional degrees of freedom for the copy_from_mg() function. These are the ones where the level degree of freedom is locally owned and the global degree of freedom is not.
Organization of the data is like for copy_indices
.
Definition at line 551 of file mg_transfer.h.

protectedinherited 
Same as above, but used to transfer solution vectors.
Definition at line 556 of file mg_transfer.h.

protectedinherited 
This variable stores whether the copy operation from the global to the level vector is actually a plain copy to the finest level. This means that the grid has no adaptive refinement and the numbering on the finest multigrid level is the same as in the global case.
Definition at line 564 of file mg_transfer.h.

protectedinherited 
This variable stores whether the copy operation from the global to the level vector is actually a plain copy to the finest level except for a renumbering within the finest level of the degrees of freedom. This means that the grid has no adaptive refinement.
Definition at line 572 of file mg_transfer.h.

protectedinherited 
The vector that stores what has been given to the set_component_to_block_map() function.
Definition at line 578 of file mg_transfer.h.

protectedinherited 
The mg_constrained_dofs of the level systems.
Definition at line 586 of file mg_transfer.h.

mutableprotectedinherited 
In the function copy_to_mg, we need to access ghosted entries of the global vector for inserting into the level vectors. This vector is populated with those entries.
Definition at line 593 of file mg_transfer.h.

mutableprotectedinherited 
Same as above but used when working with solution vectors.
Definition at line 599 of file mg_transfer.h.

mutableprotectedinherited 
In the function copy_from_mg, we access all level vectors with certain ghost entries for inserting the result into a global vector.
Definition at line 606 of file mg_transfer.h.

mutableprotectedinherited 
Same as above but used when working with solution vectors.
Definition at line 612 of file mg_transfer.h.