Reference documentation for deal.II version 9.1.0-pre
Public Types | Public Member Functions | Public Attributes | Static Public Attributes | List of all members
internal::MatrixFreeFunctions::DoFInfo Struct Reference

#include <deal.II/matrix_free/dof_info.h>

Public Types

Public Member Functions

 DoFInfo ()
 
 DoFInfo (const DoFInfo &)=default
 
void clear ()
 
unsigned int fe_index_from_degree (const unsigned int first_selected_component, const unsigned int fe_degree) const
 
template<typename number >
void read_dof_indices (const std::vector< types::global_dof_index > &local_indices, const std::vector< unsigned int > &lexicographic_inv, const AffineConstraints< number > &constraints, const unsigned int cell_number, ConstraintValues< double > &constraint_values, bool &cell_at_boundary)
 
void assign_ghosts (const std::vector< unsigned int > &boundary_cells)
 
void reorder_cells (const TaskInfo &task_info, const std::vector< unsigned int > &renumbering, const std::vector< unsigned int > &constraint_pool_row_index, const std::vector< unsigned char > &irregular_cells)
 
void compute_cell_index_compression (const std::vector< unsigned char > &irregular_cells)
 
template<int length>
void compute_face_index_compression (const std::vector< FaceToCellTopology< length >> &faces)
 
void make_connectivity_graph (const TaskInfo &task_info, const std::vector< unsigned int > &renumbering, DynamicSparsityPattern &connectivity) const
 
void compute_dof_renumbering (std::vector< types::global_dof_index > &renumbering)
 
template<int length>
void compute_vector_zero_access_pattern (const TaskInfo &task_info, const std::vector< FaceToCellTopology< length >> &faces)
 
std::size_t memory_consumption () const
 
template<typename StreamType >
void print_memory_consumption (StreamType &out, const TaskInfo &size_info) const
 
template<typename Number >
void print (const std::vector< Number > &constraint_pool_data, const std::vector< unsigned int > &constraint_pool_row_index, std::ostream &out) const
 

Public Attributes

unsigned int dimension
 
unsigned int vectorization_length
 
std::vector< IndexStorageVariantsindex_storage_variants [3]
 
std::vector< std::pair< unsigned int, unsigned int > > row_starts
 
std::vector< unsigned int > dof_indices
 
std::vector< std::pair< unsigned short, unsigned short > > constraint_indicator
 
std::vector< unsigned int > dof_indices_interleaved
 
std::vector< unsigned int > dof_indices_contiguous [3]
 
std::vector< unsigned char > n_vectorization_lanes_filled [3]
 
std::shared_ptr< const Utilities::MPI::Partitionervector_partitioner
 
std::array< std::shared_ptr< const Utilities::MPI::Partitioner >, 3 > vector_partitioner_face_variants
 
std::vector< unsigned int > constrained_dofs
 
std::vector< unsigned int > row_starts_plain_indices
 
std::vector< unsigned int > plain_dof_indices
 
unsigned int global_base_element_offset
 
unsigned int n_base_elements
 
std::vector< unsigned int > n_components
 
std::vector< unsigned int > start_components
 
std::vector< unsigned int > component_to_base_index
 
std::vector< std::vector< unsigned int > > component_dof_indices_offset
 
std::vector< unsigned int > dofs_per_cell
 
std::vector< unsigned int > dofs_per_face
 
bool store_plain_indices
 
std::vector< unsigned int > cell_active_fe_index
 
unsigned int max_fe_index
 
std::vector< std::vector< unsigned int > > fe_index_conversion
 
std::vector< types::global_dof_indexghost_dofs
 
std::vector< unsigned int > vector_zero_range_list_index
 
std::vector< unsigned int > vector_zero_range_list
 

Static Public Attributes

static const unsigned int chunk_size_zero_vector = 8192
 

Detailed Description

The class that stores the indices of the degrees of freedom for all the cells. Essentially, this is a smart number cache in the style of a DoFHandler that also embeds the description of constraints directly on the cell level without the need to refer to the external AffineConstraints object.

This class only stores index relations. The weights for hanging node constraints are stored in a different field. This is because a different field allows for the same compressed weight data on different DoFHandlers for vector-valued problems. There, the indices might be constrained differently on different components (e.g. Dirichlet conditions only on selected components), whereas the weights from hanging nodes are the same and need to be stored only once. The combination will be handled in the MatrixFree class.

Author
Katharina Kormann and Martin Kronbichler, 2010, 2011, 2018

Definition at line 66 of file dof_info.h.

Member Enumeration Documentation

Enum for various storage variants of the indices. This storage format is used to implement more efficient indexing schemes in case the underlying data structures allow for them, and to inform the access functions in FEEvaluationBase::read_write_operation() on which array to get the data from. One example of more efficient storage is the enum value IndexStorageVariants::contiguous, which means that one can get the indices to all degrees of freedom of a cell by reading only the first index for each cell, whereas all subsequent indices are merely an offset from the first index.

Enumerator
full 

This value indicates that no index compression was found and the only valid storage is to access all indices present on the cell, possibly including constraints. For a cell/face of this index type, the data access in FEEvaluationBase is directed to the array dof_indices with the index row_starts[cell_index*n_vectorization*n_components].first.

interleaved 

This value indicates that the indices are interleaved for access with vectorized gather and scatter operation. This storage variant is possible in case there are no constraints on the cell and the indices in the batch of cells are not pointing to the same global index in different slots of a vectorized array (in order to support scatter operations). For a cell/face of this index type, the data access in FEEvaluationBase is directed to the array dof_indices_interleaved with the index row_starts[cell_index*n_vectorization*n_components].first.

contiguous 

This value indicates that the indices within a cell are all contiguous, and one can get the index to the cell by reading that single value for each of the cells in the cell batch. For a cell/face of this index type, the data access in FEEvaluationBase is directed to the array dof_indices_contiguous with the index cell_index*n_vectorization*n_components.

Definition at line 237 of file dof_info.h.

Enum used to distinguish the data arrays for the vectorization type in cells and faces.

Enumerator
dof_access_face_interior 

The data index for the faces designated as interior

dof_access_face_exterior 

The data index for the faces designated as exterior

dof_access_cell 

The data index for the cells

Definition at line 275 of file dof_info.h.

Constructor & Destructor Documentation

internal::MatrixFreeFunctions::DoFInfo::DoFInfo ( )

Default empty constructor.

internal::MatrixFreeFunctions::DoFInfo::DoFInfo ( const DoFInfo )
default

Copy constructor.

Member Function Documentation

void internal::MatrixFreeFunctions::DoFInfo::clear ( )

Clear all data fields in this class.

unsigned int internal::MatrixFreeFunctions::DoFInfo::fe_index_from_degree ( const unsigned int  first_selected_component,
const unsigned int  fe_degree 
) const

Return the FE index for a given finite element degree. If not in hp mode, this function always returns index 0. If an index is not found in hp mode, it returns numbers::invalid_unsigned_int.

template<typename number >
void internal::MatrixFreeFunctions::DoFInfo::read_dof_indices ( const std::vector< types::global_dof_index > &  local_indices,
const std::vector< unsigned int > &  lexicographic_inv,
const AffineConstraints< number > &  constraints,
const unsigned int  cell_number,
ConstraintValues< double > &  constraint_values,
bool &  cell_at_boundary 
)

This internal method takes the local indices on a cell and fills them into this class. It resolves the constraints and distributes the results. Ghost indices, i.e., indices that are located on another processor, get a temporary number by this function, and will later be assigned the correct index after all the ghost indices have been collected by the call to assign_ghosts.

void internal::MatrixFreeFunctions::DoFInfo::assign_ghosts ( const std::vector< unsigned int > &  boundary_cells)

This method assigns the correct indices to ghost indices from the temporary numbering employed by the read_dof_indices function. The numbers are localized with respect to the MPI process, and ghosts start at the end of the locally owned range. This way, we get direct access to all vector entries.

void internal::MatrixFreeFunctions::DoFInfo::reorder_cells ( const TaskInfo task_info,
const std::vector< unsigned int > &  renumbering,
const std::vector< unsigned int > &  constraint_pool_row_index,
const std::vector< unsigned char > &  irregular_cells 
)

This method reorders the way cells are gone through based on a given renumbering of the cells. It also takes vectorization_length cells together and interprets them as one cell only, as is needed for vectorization.

void internal::MatrixFreeFunctions::DoFInfo::compute_cell_index_compression ( const std::vector< unsigned char > &  irregular_cells)

Finds possible compression for the cell indices that we can apply for increased efficiency. Run at the end of reorder_cells.

template<int length>
void internal::MatrixFreeFunctions::DoFInfo::compute_face_index_compression ( const std::vector< FaceToCellTopology< length >> &  faces)

Finds possible compression for the face indices that we can apply for increased efficiency. Run at the end of reorder_cells.

void internal::MatrixFreeFunctions::DoFInfo::make_connectivity_graph ( const TaskInfo task_info,
const std::vector< unsigned int > &  renumbering,
DynamicSparsityPattern connectivity 
) const

This function computes the connectivity of the currently stored indices in terms of connections between the individual cells and fills the structure into a sparsity pattern.

void internal::MatrixFreeFunctions::DoFInfo::compute_dof_renumbering ( std::vector< types::global_dof_index > &  renumbering)

Compute a renumbering of the degrees of freedom to improve the data access patterns for this class that can be utilized by the categories in the IndexStorageVariants enum. For example, the index ordering can be improved for typical DG elements by interleaving the degrees of freedom from batches of cells, which avoids the explicit data transposition in IndexStorageVariants::contiguous. Currently, these more advanced features are not implemented, so there is only limited value of this function.

template<int length>
void internal::MatrixFreeFunctions::DoFInfo::compute_vector_zero_access_pattern ( const TaskInfo task_info,
const std::vector< FaceToCellTopology< length >> &  faces 
)

Fills the array that defines how to zero selected ranges in the result vector within the cell loop, filling the two member variables vector_zero_range_list_index and vector_zero_range_list.

The intent of this pattern is to zero the vector entries in close temporal proximity to the first access and thus keeping the vector entries in cache.

std::size_t internal::MatrixFreeFunctions::DoFInfo::memory_consumption ( ) const

Return the memory consumption in bytes of this class.

template<typename StreamType >
void internal::MatrixFreeFunctions::DoFInfo::print_memory_consumption ( StreamType &  out,
const TaskInfo size_info 
) const

Prints a detailed summary of memory consumption in the different structures of this class to the given output stream.

template<typename Number >
void internal::MatrixFreeFunctions::DoFInfo::print ( const std::vector< Number > &  constraint_pool_data,
const std::vector< unsigned int > &  constraint_pool_row_index,
std::ostream &  out 
) const

Prints a representation of the indices in the class to the given output stream.

Member Data Documentation

const unsigned int internal::MatrixFreeFunctions::DoFInfo::chunk_size_zero_vector = 8192
static

This value is used to define subranges in the vectors which we can zero inside the MatrixFree::loop() call. The goal is to only clear a part of the vector at a time to keep the values that are zeroed in caches, saving one global vector access for the case where this is applied rather than vector = 0.;.

Size of the chunk is set to 64 kByte which generally fits to current caches.

Definition at line 78 of file dof_info.h.

unsigned int internal::MatrixFreeFunctions::DoFInfo::dimension

Stores the dimension of the underlying DoFHandler. Since the indices are not templated, this is the variable that makes the dimension accessible in the (rare) cases it is needed inside this class.

Definition at line 296 of file dof_info.h.

unsigned int internal::MatrixFreeFunctions::DoFInfo::vectorization_length

For efficiency reasons, always keep a fixed number of cells with similar properties together. This variable controls the number of cells batched together. As opposed to the other classes which are templated on the number type, this class as a pure index container is not templated, so we need to keep the information otherwise contained in VectorizedArray<Number>::n_array_elements.

Definition at line 306 of file dof_info.h.

std::vector<IndexStorageVariants> internal::MatrixFreeFunctions::DoFInfo::index_storage_variants[3]

Stores the index storage variant of all cell and face batches.

The three arrays given here address the types for the faces decorated as interior (0), the faces decorated with as exterior (1), and the cells (2) according to CellOrFaceAccess.

Definition at line 315 of file dof_info.h.

std::vector<std::pair<unsigned int, unsigned int> > internal::MatrixFreeFunctions::DoFInfo::row_starts

Stores the rowstart indices of the compressed row storage in the dof_indices and constraint_indicator fields. These two fields are always accessed together, so it is simpler to keep just one variable for them. This also obviates keeping two rowstart vectors in sync.

Definition at line 323 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::dof_indices

Stores the indices of the degrees of freedom for each cell. These indices are computed in MPI-local index space, i.e., each processor stores the locally owned indices as numbers between 0 and n_locally_owned_dofs-1 and ghost indices in the range n_locally_owned_dofs to n_locally_owned_dofs+n_ghost_dofs. The translation between this MPI-local index space and the global numbering of degrees of freedom is stored in the vector_partitioner data structure. This array also includes the indirect contributions from constraints, which are described by the constraint_indicator field. Because of variable lengths of rows, this would be a vector of a vector. However, we use one contiguous memory region and store the rowstart in the variable row_starts.

Definition at line 340 of file dof_info.h.

std::vector<std::pair<unsigned short, unsigned short> > internal::MatrixFreeFunctions::DoFInfo::constraint_indicator

This variable describes the position of constraints in terms of the local numbering of degrees of freedom on a cell. The first number stores the distance from one constrained degree of freedom to the next. This allows to identify the position of constrained DoFs as we loop through the local degrees of freedom of the cell when reading from or writing to a vector. The second number stores the index of the constraint weights, stored in the variable constraint_pool_data.

Definition at line 352 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::dof_indices_interleaved

Reordered index storage for IndexStorageVariants::interleaved.

Definition at line 357 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::dof_indices_contiguous[3]

Compressed index storage for faster access than through dof_indices used according to the description in IndexStorageVariants.

The three arrays given here address the types for the faces decorated as interior (0), the faces decorated with as exterior (1), and the cells (2) according to CellOrFaceAccess.

Definition at line 367 of file dof_info.h.

std::vector<unsigned char> internal::MatrixFreeFunctions::DoFInfo::n_vectorization_lanes_filled[3]

Caches the number of indices filled when vectorizing. This information can implicitly deduced from the row_starts data fields, but this field allows for faster access.

The three arrays given here address the types for the faces decorated as interior (0), the faces decorated with as exterior (1), and the cells (2) according to CellOrFaceAccess.

Definition at line 378 of file dof_info.h.

std::shared_ptr<const Utilities::MPI::Partitioner> internal::MatrixFreeFunctions::DoFInfo::vector_partitioner

This stores the parallel partitioning that can be used to set up vectors. The partitioner includes the description of the local range in the vector, and also includes how the ghosts look like. This enables initialization of vectors based on the DoFInfo field.

Definition at line 386 of file dof_info.h.

std::array<std::shared_ptr<const Utilities::MPI::Partitioner>, 3> internal::MatrixFreeFunctions::DoFInfo::vector_partitioner_face_variants

This partitioning selects a subset of ghost indices to the full vector partitioner stored in vector_partitioner. These partitioners are used in specialized loops that only import parts of the ghosted region for reducing the amount of communication. There are three variants of the partitioner initialized, one that queries only the cell values, one that additionally describes the indices for evaluating the function values on the faces, and one that describes the indices for evaluation both the function values and the gradients on the faces adjacent to the locally owned cells.

Definition at line 400 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::constrained_dofs

This stores a (sorted) list of all locally owned degrees of freedom that are constrained.

Definition at line 406 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::row_starts_plain_indices

Stores the rowstart indices of the compressed row storage in the plain_dof_indices fields.

Definition at line 412 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::plain_dof_indices

Stores the indices of the degrees of freedom for each cell. This array does not include the indirect contributions from constraints, which are included in dof_indices. Because of variable lengths of rows, this would be a vector of a vector. However, we use one contiguous memory region and store the rowstart in the variable row_starts_plain_indices.

Definition at line 422 of file dof_info.h.

unsigned int internal::MatrixFreeFunctions::DoFInfo::global_base_element_offset

Stores the offset in terms of the number of base elements over all DoFInfo objects.

Definition at line 428 of file dof_info.h.

unsigned int internal::MatrixFreeFunctions::DoFInfo::n_base_elements

Stores the number of base elements in the DoFHandler where the indices have been read from.

Definition at line 434 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::n_components

Stores the number of components of each base element in the finite element where the indices have been read from.

Definition at line 440 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::start_components

The ith entry of this vector stores the component number of the given base element.

Definition at line 446 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::component_to_base_index

For a given component in an FESystem, this variable tells which base element the index belongs to.

Definition at line 452 of file dof_info.h.

std::vector<std::vector<unsigned int> > internal::MatrixFreeFunctions::DoFInfo::component_dof_indices_offset

For a vector-valued element, this gives the constant offset in the number of degrees of freedom starting at the given component, as the degrees are numbered by degrees of freedom. This data structure does not take possible constraints and thus, shorter or longer lists, into account. This information is encoded in the row_starts variables directly.

The outer vector goes through the various fe indices in the hp case, similarly to the dofs_per_cell variable.

Definition at line 465 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::dofs_per_cell

Stores the number of degrees of freedom per cell.

Definition at line 470 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::dofs_per_face

Stores the number of degrees of freedom per face.

Definition at line 475 of file dof_info.h.

bool internal::MatrixFreeFunctions::DoFInfo::store_plain_indices

Informs on whether plain indices are cached.

Definition at line 480 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::cell_active_fe_index

Stores the index of the active finite element in the hp case.

Definition at line 485 of file dof_info.h.

unsigned int internal::MatrixFreeFunctions::DoFInfo::max_fe_index

Stores the maximum degree of different finite elements for the hp case.

Definition at line 491 of file dof_info.h.

std::vector<std::vector<unsigned int> > internal::MatrixFreeFunctions::DoFInfo::fe_index_conversion

To each of the slots in an hp adaptive case, the inner vector stores the corresponding element degree. This is used by the constructor of FEEvaluationBase to identify the correct data slot in the hp case.

Definition at line 498 of file dof_info.h.

std::vector<types::global_dof_index> internal::MatrixFreeFunctions::DoFInfo::ghost_dofs

Temporarily stores the numbers of ghosts during setup. Cleared when calling assign_ghosts. Then, all information is collected by the partitioner.

Definition at line 505 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::vector_zero_range_list_index

Stores an integer to each partition in TaskInfo that indicates whether to clear certain parts in the result vector if the user requested it with the respective argument in the MatrixFree::loop.

Definition at line 512 of file dof_info.h.

std::vector<unsigned int> internal::MatrixFreeFunctions::DoFInfo::vector_zero_range_list

Stores the actual ranges in the vector to be cleared.

Definition at line 517 of file dof_info.h.


The documentation for this struct was generated from the following file: