Reference documentation for deal.II version Git 2276b94619 20200228 10:11:55 +0100

#include <deal.II/matrix_free/matrix_free.h>
Classes  
struct  AdditionalData 
struct  DoFHandlers 
Public Member Functions  
1: Construction and initialization  
MatrixFree ()  
MatrixFree (const MatrixFree< dim, Number, VectorizedArrayType > &other)  
~MatrixFree () override=default  
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const Mapping< dim > &mapping, const DoFHandlerType &dof_handler, const AffineConstraints< number2 > &constraint, const QuadratureType &quad, const AdditionalData &additional_data=AdditionalData()) 
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const DoFHandlerType &dof_handler, const AffineConstraints< number2 > &constraint, const QuadratureType &quad, const AdditionalData &additional_data=AdditionalData()) 
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const Mapping< dim > &mapping, const DoFHandlerType &dof_handler, const AffineConstraints< number2 > &constraint, const IndexSet &locally_owned_dofs, const QuadratureType &quad, const AdditionalData &additional_data=AdditionalData()) 
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const Mapping< dim > &mapping, const std::vector< const DoFHandlerType *> &dof_handler, const std::vector< const AffineConstraints< number2 > *> &constraint, const std::vector< QuadratureType > &quad, const AdditionalData &additional_data=AdditionalData()) 
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const std::vector< const DoFHandlerType *> &dof_handler, const std::vector< const AffineConstraints< number2 > *> &constraint, const std::vector< QuadratureType > &quad, const AdditionalData &additional_data=AdditionalData()) 
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const Mapping< dim > &mapping, const std::vector< const DoFHandlerType *> &dof_handler, const std::vector< const AffineConstraints< number2 > *> &constraint, const std::vector< IndexSet > &locally_owned_set, const std::vector< QuadratureType > &quad, const AdditionalData &additional_data=AdditionalData()) 
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const Mapping< dim > &mapping, const std::vector< const DoFHandlerType *> &dof_handler, const std::vector< const AffineConstraints< number2 > *> &constraint, const QuadratureType &quad, const AdditionalData &additional_data=AdditionalData()) 
template<typename DoFHandlerType , typename QuadratureType , typename number2 >  
void  reinit (const std::vector< const DoFHandlerType *> &dof_handler, const std::vector< const AffineConstraints< number2 > *> &constraint, const QuadratureType &quad, const AdditionalData &additional_data=AdditionalData()) 
void  copy_from (const MatrixFree< dim, Number, VectorizedArrayType > &matrix_free_base) 
void  clear () 
2: Matrixfree loops  
template<typename OutVector , typename InVector >  
void  cell_loop (const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &cell_operation, OutVector &dst, const InVector &src, const bool zero_dst_vector=false) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  cell_loop (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const, const CLASS *owning_class, OutVector &dst, const InVector &src, const bool zero_dst_vector=false) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  cell_loop (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &), CLASS *owning_class, OutVector &dst, const InVector &src, const bool zero_dst_vector=false) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  cell_loop (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const, const CLASS *owning_class, OutVector &dst, const InVector &src, const std::function< void(const unsigned int, const unsigned int)> &operation_before_loop, const std::function< void(const unsigned int, const unsigned int)> &operation_after_loop, const unsigned int dof_handler_index_pre_post=0) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  cell_loop (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &), CLASS *owning_class, OutVector &dst, const InVector &src, const std::function< void(const unsigned int, const unsigned int)> &operation_before_loop, const std::function< void(const unsigned int, const unsigned int)> &operation_after_loop, const unsigned int dof_handler_index_pre_post=0) const 
template<typename OutVector , typename InVector >  
void  cell_loop (const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &cell_operation, OutVector &dst, const InVector &src, const std::function< void(const unsigned int, const unsigned int)> &operation_before_loop, const std::function< void(const unsigned int, const unsigned int)> &operation_after_loop, const unsigned int dof_handler_index_pre_post=0) const 
template<typename OutVector , typename InVector >  
void  loop (const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &cell_operation, const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &face_operation, const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &boundary_operation, OutVector &dst, const InVector &src, const bool zero_dst_vector=false, const DataAccessOnFaces dst_vector_face_access=DataAccessOnFaces::unspecified, const DataAccessOnFaces src_vector_face_access=DataAccessOnFaces::unspecified) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  loop (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const, void(CLASS::*face_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const, void(CLASS::*boundary_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const, const CLASS *owning_class, OutVector &dst, const InVector &src, const bool zero_dst_vector=false, const DataAccessOnFaces dst_vector_face_access=DataAccessOnFaces::unspecified, const DataAccessOnFaces src_vector_face_access=DataAccessOnFaces::unspecified) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  loop (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &), void(CLASS::*face_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &), void(CLASS::*boundary_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &), CLASS *owning_class, OutVector &dst, const InVector &src, const bool zero_dst_vector=false, const DataAccessOnFaces dst_vector_face_access=DataAccessOnFaces::unspecified, const DataAccessOnFaces src_vector_face_access=DataAccessOnFaces::unspecified) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  loop_cell_centric (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const, const CLASS *owning_class, OutVector &dst, const InVector &src, const bool zero_dst_vector=false, const DataAccessOnFaces src_vector_face_access=DataAccessOnFaces::unspecified) const 
template<typename CLASS , typename OutVector , typename InVector >  
void  loop_cell_centric (void(CLASS::*cell_operation)(const MatrixFree &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &), CLASS *owning_class, OutVector &dst, const InVector &src, const bool zero_dst_vector=false, const DataAccessOnFaces src_vector_face_access=DataAccessOnFaces::unspecified) const 
std::pair< unsigned int, unsigned int >  create_cell_subrange_hp (const std::pair< unsigned int, unsigned int > &range, const unsigned int fe_degree, const unsigned int dof_handler_index=0) const 
std::pair< unsigned int, unsigned int >  create_cell_subrange_hp_by_index (const std::pair< unsigned int, unsigned int > &range, const unsigned int fe_index, const unsigned int dof_handler_index=0) const 
3: Initialization of vectors  
template<typename VectorType >  
void  initialize_dof_vector (VectorType &vec, const unsigned int dof_handler_index=0) const 
template<typename Number2 >  
void  initialize_dof_vector (LinearAlgebra::distributed::Vector< Number2 > &vec, const unsigned int dof_handler_index=0) const 
const std::shared_ptr< const Utilities::MPI::Partitioner > &  get_vector_partitioner (const unsigned int dof_handler_index=0) const 
const IndexSet &  get_locally_owned_set (const unsigned int dof_handler_index=0) const 
const IndexSet &  get_ghost_set (const unsigned int dof_handler_index=0) const 
const std::vector< unsigned int > &  get_constrained_dofs (const unsigned int dof_handler_index=0) const 
void  renumber_dofs (std::vector< types::global_dof_index > &renumbering, const unsigned int dof_handler_index=0) 
5: Access of internal data structure  
Note: Expert mode, interface not stable between releases.  
const internal::MatrixFreeFunctions::TaskInfo &  get_task_info () const 
const internal::MatrixFreeFunctions::MappingInfo< dim, Number, VectorizedArrayType > &  get_mapping_info () const 
const internal::MatrixFreeFunctions::DoFInfo &  get_dof_info (const unsigned int dof_handler_index_component=0) const 
unsigned int  n_constraint_pool_entries () const 
const Number *  constraint_pool_begin (const unsigned int pool_index) const 
const Number *  constraint_pool_end (const unsigned int pool_index) const 
const internal::MatrixFreeFunctions::ShapeInfo< VectorizedArrayType > &  get_shape_info (const unsigned int dof_handler_index_component=0, const unsigned int quad_index=0, const unsigned int fe_base_element=0, const unsigned int hp_active_fe_index=0, const unsigned int hp_active_quad_index=0) const 
const internal::MatrixFreeFunctions::FaceToCellTopology< VectorizedArrayType::n_array_elements > &  get_face_info (const unsigned int face_batch_number) const 
const Table< 3, unsigned int > &  get_cell_and_face_to_plain_faces () const 
AlignedVector< VectorizedArrayType > *  acquire_scratch_data () const 
void  release_scratch_data (const AlignedVector< VectorizedArrayType > *memory) const 
AlignedVector< Number > *  acquire_scratch_data_non_threadsafe () const 
void  release_scratch_data_non_threadsafe (const AlignedVector< Number > *memory) const 
Public Member Functions inherited from Subscriptor  
Subscriptor ()  
Subscriptor (const Subscriptor &)  
Subscriptor (Subscriptor &&) noexcept  
virtual  ~Subscriptor () 
Subscriptor &  operator= (const Subscriptor &) 
Subscriptor &  operator= (Subscriptor &&) noexcept 
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 
template<class Archive >  
void  serialize (Archive &ar, const unsigned int version) 
Static Public Attributes  
static const unsigned int  dimension = dim 
Private Member Functions  
template<typename number2 >  
void  internal_reinit (const Mapping< dim > &mapping, const std::vector< const DoFHandler< dim > *> &dof_handler, const std::vector< const AffineConstraints< number2 > *> &constraint, const std::vector< IndexSet > &locally_owned_set, const std::vector< hp::QCollection< 1 >> &quad, const AdditionalData &additional_data) 
template<typename number2 >  
void  internal_reinit (const Mapping< dim > &mapping, const std::vector< const hp::DoFHandler< dim > *> &dof_handler, const std::vector< const AffineConstraints< number2 > *> &constraint, const std::vector< IndexSet > &locally_owned_set, const std::vector< hp::QCollection< 1 >> &quad, const AdditionalData &additional_data) 
template<typename number2 >  
void  initialize_indices (const std::vector< const AffineConstraints< number2 > *> &constraint, const std::vector< IndexSet > &locally_owned_set, const AdditionalData &additional_data) 
void  initialize_dof_handlers (const std::vector< const DoFHandler< dim > *> &dof_handlers, const AdditionalData &additional_data) 
void  initialize_dof_handlers (const std::vector< const hp::DoFHandler< dim > *> &dof_handlers, const AdditionalData &additional_data) 
void  make_connectivity_graph_faces (DynamicSparsityPattern &connectivity) 
Private Attributes  
DoFHandlers  dof_handlers 
std::vector< internal::MatrixFreeFunctions::DoFInfo >  dof_info 
std::vector< Number >  constraint_pool_data 
std::vector< unsigned int >  constraint_pool_row_index 
internal::MatrixFreeFunctions::MappingInfo< dim, Number, VectorizedArrayType >  mapping_info 
Table< 4, internal::MatrixFreeFunctions::ShapeInfo< VectorizedArrayType > >  shape_info 
std::vector< std::pair< unsigned int, unsigned int > >  cell_level_index 
unsigned int  cell_level_index_end_local 
internal::MatrixFreeFunctions::TaskInfo  task_info 
internal::MatrixFreeFunctions::FaceInfo< VectorizedArrayType::n_array_elements >  face_info 
bool  indices_are_initialized 
bool  mapping_is_initialized 
Threads::ThreadLocalStorage< std::list< std::pair< bool, AlignedVector< VectorizedArrayType > > > >  scratch_pad 
std::list< std::pair< bool, AlignedVector< Number > > >  scratch_pad_non_threadsafe 
unsigned int  mg_level 
Related Functions  
(Note that these are not member functions.)  
template<int dim>  
unsigned int  q_point_id_in_cell (const unsigned int n_q_points_1d) 
template<int dim, typename Number >  
unsigned int  local_q_point_id (const unsigned int cell, const typename CUDAWrappers::MatrixFree< dim, Number >::Data *data, const unsigned int n_q_points_1d, const unsigned int n_q_points) 
template<int dim, typename Number >  
CUDAWrappers::MatrixFree< dim, Number >::point_type &  get_quadrature_point (const unsigned int cell, const typename CUDAWrappers::MatrixFree< dim, Number >::Data *data, const unsigned int n_q_points_1d) 
4: General information  
unsigned int  n_components () const 
unsigned int  n_base_elements (const unsigned int dof_handler_index) const 
unsigned int  n_physical_cells () const 
unsigned int  n_macro_cells () const 
unsigned int  n_cell_batches () const 
unsigned int  n_ghost_cell_batches () const 
unsigned int  n_inner_face_batches () const 
unsigned int  n_boundary_face_batches () const 
unsigned int  n_ghost_inner_face_batches () const 
types::boundary_id  get_boundary_id (const unsigned int macro_face) const 
std::array< types::boundary_id, VectorizedArrayType::n_array_elements >  get_faces_by_cells_boundary_id (const unsigned int macro_cell, const unsigned int face_number) const 
template<typename DoFHandlerType = DoFHandler<dim>>  
const DoFHandlerType &  get_dof_handler (const unsigned int dof_handler_index=0) const 
DoFHandler< dim >::cell_iterator  get_cell_iterator (const unsigned int macro_cell_number, const unsigned int vector_number, const unsigned int dof_handler_index=0) const 
std::pair< int, int >  get_cell_level_and_index (const unsigned int macro_cell_number, const unsigned int vector_number) const 
std::pair< typename DoFHandler< dim >::cell_iterator, unsigned int >  get_face_iterator (const unsigned int face_batch_number, const unsigned int vector_number, const bool interior=true, const unsigned int fe_component=0) const 
hp::DoFHandler< dim >::active_cell_iterator  get_hp_cell_iterator (const unsigned int macro_cell_number, const unsigned int vector_number, const unsigned int dof_handler_index=0) const 
bool  at_irregular_cell (const unsigned int macro_cell_number) const 
unsigned int  n_components_filled (const unsigned int cell_batch_number) const 
unsigned int  n_active_entries_per_cell_batch (const unsigned int cell_batch_number) const 
unsigned int  n_active_entries_per_face_batch (const unsigned int face_batch_number) const 
unsigned int  get_dofs_per_cell (const unsigned int dof_handler_index=0, const unsigned int hp_active_fe_index=0) const 
unsigned int  get_n_q_points (const unsigned int quad_index=0, const unsigned int hp_active_fe_index=0) const 
unsigned int  get_dofs_per_face (const unsigned int dof_handler_index=0, const unsigned int hp_active_fe_index=0) const 
unsigned int  get_n_q_points_face (const unsigned int quad_index=0, const unsigned int hp_active_fe_index=0) const 
const Quadrature< dim > &  get_quadrature (const unsigned int quad_index=0, const unsigned int hp_active_fe_index=0) const 
const Quadrature< dim  1 > &  get_face_quadrature (const unsigned int quad_index=0, const unsigned int hp_active_fe_index=0) const 
unsigned int  get_cell_category (const unsigned int macro_cell) const 
std::pair< unsigned int, unsigned int >  get_face_category (const unsigned int macro_face) const 
bool  indices_initialized () const 
bool  mapping_initialized () const 
unsigned int  get_mg_level () const 
std::size_t  memory_consumption () const 
template<typename StreamType >  
void  print_memory_consumption (StreamType &out) const 
void  print (std::ostream &out) const 
template<int spacedim>  
static bool  is_supported (const FiniteElement< dim, spacedim > &fe) 
Additional Inherited Members  
Static Public Member Functions inherited from Subscriptor  
static ::ExceptionBase &  ExcInUse (int arg1, std::string arg2, std::string arg3) 
static ::ExceptionBase &  ExcNoSubscriber (std::string arg1, std::string arg2) 
This class collects all the data that is stored for the matrix free implementation. The storage scheme is tailored towards several loops performed with the same data, i.e., typically doing many matrixvector products or residual computations on the same mesh. The class is used in step37 and step48.
This class does not implement any operations involving finite element basis functions, i.e., regarding the operation performed on the cells. For these operations, the class FEEvaluation is designed to use the data collected in this class.
The stored data can be subdivided into three main components:
Besides the initialization routines, this class implements only a single operation, namely a loop over all cells (cell_loop()). This loop is scheduled in such a way that cells that share degrees of freedom are not worked on simultaneously, which implies that it is possible to write to vectors (or matrices) in parallel without having to explicitly synchronize access to these vectors and matrices. This class does not implement any shape values, all it does is to cache the respective data. To implement finite element operations, use the class FEEvaluation (or some of the related classes).
This class traverses the cells in a different order than the usual Triangulation class in deal.II, in order to be flexible with respect to parallelization in shared memory and vectorization.
Vectorization is implemented by merging several topological cells into one socalled macro cell. This enables the application of all cellrelated operations for several cells with one CPU instruction and is one of the main features of this framework.
For details on usage of this class, see the description of FEEvaluation or the matrixfree module.
Definition at line 117 of file matrix_free.h.
using MatrixFree< dim, Number, VectorizedArrayType >::value_type = Number 
An alias for the underlying number type specified by the template argument.
Definition at line 128 of file matrix_free.h.

strong 
This class defines the type of data access for face integrals in loop () that is passed on to the update_ghost_values
and compress
functions of the parallel vectors, with the purpose of being able to reduce the amount of data that must be exchanged. The data exchange is a real bottleneck in particular for highdegree DG methods, therefore a more restrictive way of exchange is clearly beneficial. Note that this selection applies to FEFaceEvaluation objects assigned to the exterior side of cells accessing FaceToCellTopology::exterior_cells
only; all interior objects are available in any case.
Enumerator  

none  The loop does not involve any FEFaceEvaluation access into neighbors, as is the case with only boundary integrals (but no interior face integrals) or when doing mass matrices in a MatrixFree::cell_loop() like setup. 
values  The loop does only involve FEFaceEvaluation access into neighbors by function values, such as 
values_all_faces  Same as above. To be used if data has to be accessed from exterior faces if FEFaceEvaluation was reinitialized by providing the cell batch number and a face number. This configuration is useful in the context of cellcentric loops.

gradients  The loop does involve FEFaceEvaluation access into neighbors by function values and gradients, but no second derivatives, such as 
gradients_all_faces  Same as above. To be used if data has to be accessed from exterior faces if FEFaceEvaluation was reinitialized by providing the cell batch number and a face number. This configuration is useful in the context of cellcentric loops.

unspecified  General setup where the user does not want to make a restriction. This is typically more expensive than the other options, but also the most conservative one because the full data of elements behind the faces to be computed locally will be exchanged. 
Definition at line 707 of file matrix_free.h.
MatrixFree< dim, Number, VectorizedArrayType >::MatrixFree  (  ) 
Default empty constructor. Does nothing.
MatrixFree< dim, Number, VectorizedArrayType >::MatrixFree  (  const MatrixFree< dim, Number, VectorizedArrayType > &  other  ) 
Copy constructor, calls copy_from

overridedefault 
Destructor.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const Mapping< dim > &  mapping, 
const DoFHandlerType &  dof_handler,  
const AffineConstraints< number2 > &  constraint,  
const QuadratureType &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Extracts the information needed to perform loops over cells. The DoFHandler and AffineConstraints objects describe the layout of degrees of freedom, the DoFHandler and the mapping describe the transformations from unit to real cell, and the finite element underlying the DoFHandler together with the quadrature formula describe the local operations. Note that the finite element underlying the DoFHandler must either be scalar or contain several copies of the same element. Mixing several different elements into one FESystem is not allowed. In that case, use the initialization function with several DoFHandler arguments.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const DoFHandlerType &  dof_handler, 
const AffineConstraints< number2 > &  constraint,  
const QuadratureType &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Initializes the data structures. Same as above, but using a \(Q_1\) mapping.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const Mapping< dim > &  mapping, 
const DoFHandlerType &  dof_handler,  
const AffineConstraints< number2 > &  constraint,  
const IndexSet &  locally_owned_dofs,  
const QuadratureType &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Same as above.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const Mapping< dim > &  mapping, 
const std::vector< const DoFHandlerType *> &  dof_handler,  
const std::vector< const AffineConstraints< number2 > *> &  constraint,  
const std::vector< QuadratureType > &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Extracts the information needed to perform loops over cells. The DoFHandler and AffineConstraints objects describe the layout of degrees of freedom, the DoFHandler and the mapping describe the transformations from unit to real cell, and the finite element underlying the DoFHandler together with the quadrature formula describe the local operations. As opposed to the scalar case treated with the other initialization functions, this function allows for problems with two or more different finite elements. The DoFHandlers to each element must be passed as pointers to the initialization function. Alternatively, a system of several components may also be represented by a single DoFHandler with an FESystem element. The prerequisite for this case is that each base element of the FESystem must be compatible with the present class, such as the FE_Q or FE_DGQ classes.
This function also allows for using several quadrature formulas, e.g. when the description contains independent integrations of elements of different degrees. However, the number of different quadrature formulas can be sets independently from the number of DoFHandlers, when several elements are always integrated with the same quadrature formula.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const std::vector< const DoFHandlerType *> &  dof_handler, 
const std::vector< const AffineConstraints< number2 > *> &  constraint,  
const std::vector< QuadratureType > &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Initializes the data structures. Same as above, but using a \(Q_1\) mapping.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const Mapping< dim > &  mapping, 
const std::vector< const DoFHandlerType *> &  dof_handler,  
const std::vector< const AffineConstraints< number2 > *> &  constraint,  
const std::vector< IndexSet > &  locally_owned_set,  
const std::vector< QuadratureType > &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Same as above.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const Mapping< dim > &  mapping, 
const std::vector< const DoFHandlerType *> &  dof_handler,  
const std::vector< const AffineConstraints< number2 > *> &  constraint,  
const QuadratureType &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Initializes the data structures. Same as before, but now the index set description of the locally owned range of degrees of freedom is taken from the DoFHandler. Moreover, only a single quadrature formula is used, as might be necessary when several components in a vectorvalued problem are integrated together based on the same quadrature formula.
void MatrixFree< dim, Number, VectorizedArrayType >::reinit  (  const std::vector< const DoFHandlerType *> &  dof_handler, 
const std::vector< const AffineConstraints< number2 > *> &  constraint,  
const QuadratureType &  quad,  
const AdditionalData &  additional_data = AdditionalData() 

) 
Initializes the data structures. Same as above, but using a \(Q_1\) mapping.
void MatrixFree< dim, Number, VectorizedArrayType >::copy_from  (  const MatrixFree< dim, Number, VectorizedArrayType > &  matrix_free_base  ) 
Copy function. Creates a deep copy of all data structures. It is usually enough to keep the data for different operations once, so this function should not be needed very often.
void MatrixFree< dim, Number, VectorizedArrayType >::clear  (  ) 
Clear all data fields and brings the class into a condition similar to after having called the default constructor.
void MatrixFree< dim, Number, VectorizedArrayType >::cell_loop  (  const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &  cell_operation, 
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false 

)  const 
This method runs the loop over all cells (in parallel) and performs the MPI data exchange on the source vector and destination vector.
cell_operation  std::function with the signature cell_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) where the first argument passes the data of the calling class and the last argument defines the range of cells which should be worked on (typically more than one cell should be worked on in order to reduce overheads). One can pass a pointer to an object in this place if it has an operator() with the correct set of arguments since such a pointer can be converted to the function object. 
dst  Destination vector holding the result. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::compress() at the end of the call internally. For other vectors, including parallel Trilinos or PETSc vectors, no such call is issued. Note that Trilinos/Epetra or PETSc vectors do currently not work in parallel because the present class uses MPIlocal index addressing, as opposed to the global addressing implied by those external libraries. 
src  Input vector. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::update_ghost_values() at the start of the call internally to make sure all necessary data is locally available. Note, however, that the vector is reset to its original state at the end of the loop, i.e., if the vector was not ghosted upon entry of the loop, it will not be ghosted upon finishing the loop. 
zero_dst_vector  If this flag is set to true , the vector dst will be set to zero inside the loop. Use this case in case you perform a typical vmult() operation on a matrix object, as it will typically be faster than calling dst = 0; before the loop separately. This is because the vector entries are set to zero only on subranges of the vector, making sure that the vector entries stay in caches as much as possible. 
void MatrixFree< dim, Number, VectorizedArrayType >::cell_loop  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const  cell_operation, 
const CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false 

)  const 
This is the second variant to run the loop over all cells, now providing a function pointer to a member function of class CLASS
. This method obviates the need to define a lambda function or to call std::bind to bind the class into the given function in case the local function needs to access data in the class (i.e., it is a nonstatic member function).
cell_operation  Pointer to member function of CLASS with the signature cell_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) where the first argument passes the data of the calling class and the last argument defines the range of cells which should be worked on (typically more than one cell should be worked on in order to reduce overheads). 
owning_class  The object which provides the cell_operation call. To be compatible with this interface, the class must allow to call owning_class>cell_operation(...) . 
dst  Destination vector holding the result. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::compress() at the end of the call internally. For other vectors, including parallel Trilinos or PETSc vectors, no such call is issued. Note that Trilinos/Epetra or PETSc vectors do currently not work in parallel because the present class uses MPIlocal index addressing, as opposed to the global addressing implied by those external libraries. 
src  Input vector. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::update_ghost_values() at the start of the call internally to make sure all necessary data is locally available. Note, however, that the vector is reset to its original state at the end of the loop, i.e., if the vector was not ghosted upon entry of the loop, it will not be ghosted upon finishing the loop. 
zero_dst_vector  If this flag is set to true , the vector dst will be set to zero inside the loop. Use this case in case you perform a typical vmult() operation on a matrix object, as it will typically be faster than calling dst = 0; before the loop separately. This is because the vector entries are set to zero only on subranges of the vector, making sure that the vector entries stay in caches as much as possible. 
void MatrixFree< dim, Number, VectorizedArrayType >::cell_loop  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)  cell_operation, 
CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false 

)  const 
Same as above, but for class member functions which are nonconst.
void MatrixFree< dim, Number, VectorizedArrayType >::cell_loop  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const  cell_operation, 
const CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const std::function< void(const unsigned int, const unsigned int)> &  operation_before_loop,  
const std::function< void(const unsigned int, const unsigned int)> &  operation_after_loop,  
const unsigned int  dof_handler_index_pre_post = 0 

)  const 
This function is similar to the cell_loop with an std::function object to specify to operation to be performed on cells, but adds two additional functors to execute some additional work before and after the cell integrals are computed.
The two additional functors work on a range of degrees of freedom, expressed in terms of the degreeoffreedom numbering of the selected DoFHandler dof_handler_index_pre_post
in MPIlocal indices. The arguments to the functors represent a range of degrees of freedom at a granularity of internal::MatrixFreeFunctions::DoFInfo::chunk_size_zero_vector entries (except for the last chunk which is set to the number of locally owned entries) in the form [first, last)
. The idea of these functors is to bring operations on vectors closer to the point where they accessed in a matrixfree loop, with the goal to increase cache hits by temporal locality. This loop guarantees that the operation_before_loop
hits all relevant unknowns before they are first touched in the cell_operation (including the MPI data exchange), allowing to execute some vector update that the src
vector depends upon. The operation_after_loop
is similar
cell_operation
(including the MPI data exchange), allowing e.g. to compute some vector operations that depend on the result of the current cell loop in dst
or want to modify src
. The efficiency of caching depends on the numbering of the degrees of freedom because of the granularity of the ranges.cell_operation  Pointer to member function of CLASS with the signature cell_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) where the first argument passes the data of the calling class and the last argument defines the range of cells which should be worked on (typically more than one cell should be worked on in order to reduce overheads). 
owning_class  The object which provides the cell_operation call. To be compatible with this interface, the class must allow to call owning_class>cell_operation(...) . 
dst  Destination vector holding the result. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::compress() at the end of the call internally. For other vectors, including parallel Trilinos or PETSc vectors, no such call is issued. Note that Trilinos/Epetra or PETSc vectors do currently not work in parallel because the present class uses MPIlocal index addressing, as opposed to the global addressing implied by those external libraries. 
src  Input vector. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::update_ghost_values() at the start of the call internally to make sure all necessary data is locally available. Note, however, that the vector is reset to its original state at the end of the loop, i.e., if the vector was not ghosted upon entry of the loop, it will not be ghosted upon finishing the loop. 
operation_before_loop  This functor can be used to perform an operation on entries of the src and dst vectors (or other vectors) before the operation on cells first touches a particular DoF according to the general description in the text above. This function is passed a range of the locally owned degrees of freedom on the selected dof_handler_index_pre_post (in MPIlocal numbering). 
operation_after_loop  This functor can be used to perform an operation on entries of the src and dst vectors (or other vectors) after the operation on cells last touches a particular DoF according to the general description in the text above. This function is passed a range of the locally owned degrees of freedom on the selected dof_handler_index_pre_post (in MPIlocal numbering). 
dof_handler_index_pre_post  Since MatrixFree can be initialized with a vector of DoFHandler objects, each of them will in general have vector sizes and thus different ranges returned to operation_before_loop and operation_after_loop . Use this variable to specify which one of the DoFHandler objects the index range should be associated to. Defaults to the dof_handler_index 0. 
operation_before_loop
and operation_after_loop
is currently only implemented for the MPIonly case. In case threading is enabled, the complete operation_before_loop
is scheduled before the parallel loop, and operation_after_loop
is scheduled strictly afterwards, due to the complicated dependencies. void MatrixFree< dim, Number, VectorizedArrayType >::cell_loop  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)  cell_operation, 
CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const std::function< void(const unsigned int, const unsigned int)> &  operation_before_loop,  
const std::function< void(const unsigned int, const unsigned int)> &  operation_after_loop,  
const unsigned int  dof_handler_index_pre_post = 0 

)  const 
Same as above, but for class member functions which are nonconst.
void MatrixFree< dim, Number, VectorizedArrayType >::cell_loop  (  const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &  cell_operation, 
OutVector &  dst,  
const InVector &  src,  
const std::function< void(const unsigned int, const unsigned int)> &  operation_before_loop,  
const std::function< void(const unsigned int, const unsigned int)> &  operation_after_loop,  
const unsigned int  dof_handler_index_pre_post = 0 

)  const 
Same as above, but taking an std::function
as the cell_operation
rather than a class member function.
void MatrixFree< dim, Number, VectorizedArrayType >::loop  (  const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &  cell_operation, 
const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &  face_operation,  
const std::function< void(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)> &  boundary_operation,  
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false , 

const DataAccessOnFaces  dst_vector_face_access = DataAccessOnFaces::unspecified , 

const DataAccessOnFaces  src_vector_face_access = DataAccessOnFaces::unspecified 

)  const 
This method runs a loop over all cells (in parallel) and performs the MPI data exchange on the source vector and destination vector. As opposed to the other variants that only runs a function on cells, this method also takes as arguments a function for the interior faces and for the boundary faces, respectively.
cell_operation  std::function with the signature cell_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) where the first argument passes the data of the calling class and the last argument defines the range of cells which should be worked on (typically more than one cell should be worked on in order to reduce overheads). One can pass a pointer to an object in this place if it has an operator() with the correct set of arguments since such a pointer can be converted to the function object. 
face_operation  std::function with the signature face_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) in analogy to cell_operation , but now the part associated to the work on interior faces. Note that the MatrixFree framework treats periodic faces as interior ones, so they will be assigned their correct neighbor after applying periodicity constraints within the face_operation calls. 
boundary_operation  std::function with the signature boundary_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) in analogy to cell_operation and face_operation , but now the part associated to the work on boundary faces. Boundary faces are separated by their boundary_id and it is possible to query that id using MatrixFree::get_boundary_id(). Note that both interior and faces use the same numbering, and faces in the interior are assigned lower numbers than the boundary faces. 
dst  Destination vector holding the result. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::compress() at the end of the call internally. 
src  Input vector. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::update_ghost_values() at the start of the call internally to make sure all necessary data is locally available. Note, however, that the vector is reset to its original state at the end of the loop, i.e., if the vector was not ghosted upon entry of the loop, it will not be ghosted upon finishing the loop. 
zero_dst_vector  If this flag is set to true , the vector dst will be set to zero inside the loop. Use this case in case you perform a typical vmult() operation on a matrix object, as it will typically be faster than calling dst = 0; before the loop separately. This is because the vector entries are set to zero only on subranges of the vector, making sure that the vector entries stay in caches as much as possible. 
dst_vector_face_access  Set the type of access into the vector dst that will happen inside the body of the face_operation function. As explained in the description of the DataAccessOnFaces struct, the purpose of this selection is to reduce the amount of data that must be exchanged over the MPI network (or via memcpy if within the shared memory region of a node) to gain performance. Note that there is no way to communicate this setting with the FEFaceEvaluation class, therefore this selection must be made at this site in addition to what is implemented inside the face_operation function. As a consequence, there is also no way to check that the setting passed to this call is consistent with what is later done by FEFaceEvaluation , and it is the user's responsibility to ensure correctness of data. 
src_vector_face_access  Set the type of access into the vector src that will happen inside the body of the face_operation function, in analogy to dst_vector_face_access . 
void MatrixFree< dim, Number, VectorizedArrayType >::loop  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const  cell_operation, 
void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const  face_operation,  
void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const  boundary_operation,  
const CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false , 

const DataAccessOnFaces  dst_vector_face_access = DataAccessOnFaces::unspecified , 

const DataAccessOnFaces  src_vector_face_access = DataAccessOnFaces::unspecified 

)  const 
This is the second variant to run the loop over all cells, interior faces, and boundary faces, now providing three function pointers to member functions of class CLASS
with the signature operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int>&)const
. This method obviates the need to define a lambda function or to call std::bind to bind the class into the given function in case the local function needs to access data in the class (i.e., it is a nonstatic member function).
cell_operation  Pointer to member function of CLASS with the signature cell_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) where the first argument passes the data of the calling class and the last argument defines the range of cells which should be worked on (typically more than one cell should be worked on in order to reduce overheads). Note that the loop will typically split the cell_range into smaller pieces and work on cell_operation , face_operation , and boundary_operation alternately, in order to increase the potential reuse of vector entries in caches. 
face_operation  Pointer to member function of CLASS with the signature face_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) in analogy to cell_operation , but now the part associated to the work on interior faces. Note that the MatrixFree framework treats periodic faces as interior ones, so they will be assigned their correct neighbor after applying periodicity constraints within the face_operation calls. 
boundary_operation  Pointer to member function of CLASS with the signature boundary_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) in analogy to cell_operation and face_operation , but now the part associated to the work on boundary faces. Boundary faces are separated by their boundary_id and it is possible to query that id using MatrixFree::get_boundary_id(). Note that both interior and faces use the same numbering, and faces in the interior are assigned lower numbers than the boundary faces. 
owning_class  The object which provides the cell_operation call. To be compatible with this interface, the class must allow to call owning_class>cell_operation(...) , owning_class>face_operation(...) , and owning_class>boundary_operation(...) . 
dst  Destination vector holding the result. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::compress() at the end of the call internally. 
src  Input vector. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::update_ghost_values() at the start of the call internally to make sure all necessary data is locally available. Note, however, that the vector is reset to its original state at the end of the loop, i.e., if the vector was not ghosted upon entry of the loop, it will not be ghosted upon finishing the loop. 
zero_dst_vector  If this flag is set to true , the vector dst will be set to zero inside the loop. Use this case in case you perform a typical vmult() operation on a matrix object, as it will typically be faster than calling dst = 0; before the loop separately. This is because the vector entries are set to zero only on subranges of the vector, making sure that the vector entries stay in caches as much as possible. 
dst_vector_face_access  Set the type of access into the vector dst that will happen inside the body of the face_operation function. As explained in the description of the DataAccessOnFaces struct, the purpose of this selection is to reduce the amount of data that must be exchanged over the MPI network (or via memcpy if within the shared memory region of a node) to gain performance. Note that there is no way to communicate this setting with the FEFaceEvaluation class, therefore this selection must be made at this site in addition to what is implemented inside the face_operation function. As a consequence, there is also no way to check that the setting passed to this call is consistent with what is later done by FEFaceEvaluation , and it is the user's responsibility to ensure correctness of data. 
src_vector_face_access  Set the type of access into the vector src that will happen inside the body of the face_operation function, in analogy to dst_vector_face_access . 
void MatrixFree< dim, Number, VectorizedArrayType >::loop  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)  cell_operation, 
void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)  face_operation,  
void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)  boundary_operation,  
CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false , 

const DataAccessOnFaces  dst_vector_face_access = DataAccessOnFaces::unspecified , 

const DataAccessOnFaces  src_vector_face_access = DataAccessOnFaces::unspecified 

)  const 
Same as above, but for class member functions which are nonconst.
void MatrixFree< dim, Number, VectorizedArrayType >::loop_cell_centric  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &) const  cell_operation, 
const CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false , 

const DataAccessOnFaces  src_vector_face_access = DataAccessOnFaces::unspecified 

)  const 
This method runs the loop over all cells (in parallel) similarly as cell_loop() does. However, this function is intended to be used for the case if face and boundary integrals should be also evaluated. In contrast to loop(), the user provides only a single function that should contain the cell integral over a cell (or batch of cells when vectorizing) and the face and boundary integrals over all its faces. This is referred to in the literature as elementcentric loop
or cellcentric loop
.
To be able to evaluate all face integrals (with values or gradients from the neighboring cells), all ghost values from neighboring cells are updated. Use FEFaceEvalution::reinit(cell, face_no) to access quantities on arbitrary faces of a cell and the respective neighbors.
cell_operation  Pointer to member function of CLASS with the signature cell_operation (const MatrixFree<dim,Number> &, OutVector &, InVector &, std::pair<unsigned int,unsigned int> &) where the first argument passes the data of the calling class and the last argument defines the range of cells which should be worked on (typically more than one cell is passed in from the loop in order to reduce overheads). 
owning_class  The object which provides the cell_operation call. To be compatible with this interface, the class must allow to call owning_class>cell_operation(...) . 
dst  Destination vector holding the result. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::compress() at the end of the call internally. 
src  Input vector. If the vector is of type LinearAlgebra::distributed::Vector (or composite objects thereof such as LinearAlgebra::distributed::BlockVector), the loop calls LinearAlgebra::distributed::Vector::update_ghost_values() at the start of the call internally to make sure all necessary data is locally available. Note, however, that the vector is reset to its original state at the end of the loop, i.e., if the vector was not ghosted upon entry of the loop, it will not be ghosted upon finishing the loop. 
zero_dst_vector  If this flag is set to true , the vector dst will be set to zero inside the loop. Use this case in case you perform a typical vmult() operation on a matrix object, as it will typically be faster than calling dst = 0; before the loop separately. This is because the vector entries are set to zero only on subranges of the vector, making sure that the vector entries stay in caches as much as possible. 
src_vector_face_access  Set the type of access into the vector src that will happen inside the body of the cell_operation function during face integrals. As explained in the description of the DataAccessOnFaces struct, the purpose of this selection is to reduce the amount of data that must be exchanged over the MPI network (or via memcpy if within the shared memory region of a node) to gain performance. Note that there is no way to communicate this setting with the FEFaceEvaluation class, therefore this selection must be made at this site in addition to what is implemented inside the face_operation function. As a consequence, there is also no way to check that the setting passed to this call is consistent with what is later done by FEFaceEvaluation , and it is the user's responsibility to ensure correctness of data. 
void MatrixFree< dim, Number, VectorizedArrayType >::loop_cell_centric  (  void(CLASS::*)(const MatrixFree< dim, Number, VectorizedArrayType > &, OutVector &, const InVector &, const std::pair< unsigned int, unsigned int > &)  cell_operation, 
CLASS *  owning_class,  
OutVector &  dst,  
const InVector &  src,  
const bool  zero_dst_vector = false , 

const DataAccessOnFaces  src_vector_face_access = DataAccessOnFaces::unspecified 

)  const 
Same as above, but for the class member function which is nonconst.
std::pair<unsigned int, unsigned int> MatrixFree< dim, Number, VectorizedArrayType >::create_cell_subrange_hp  (  const std::pair< unsigned int, unsigned int > &  range, 
const unsigned int  fe_degree,  
const unsigned int  dof_handler_index = 0 

)  const 
In the hp adaptive case, a subrange of cells as computed during the cell loop might contain elements of different degrees. Use this function to compute what the subrange for an individual finite element degree is. The finite element degree is associated to the vector component given in the function call.
std::pair<unsigned int, unsigned int> MatrixFree< dim, Number, VectorizedArrayType >::create_cell_subrange_hp_by_index  (  const std::pair< unsigned int, unsigned int > &  range, 
const unsigned int  fe_index,  
const unsigned int  dof_handler_index = 0 

)  const 
In the hp adaptive case, a subrange of cells as computed during the cell loop might contain elements of different degrees. Use this function to compute what the subrange for a given index the hp finite element, as opposed to the finite element degree in the other function.
void MatrixFree< dim, Number, VectorizedArrayType >::initialize_dof_vector  (  VectorType &  vec, 
const unsigned int  dof_handler_index = 0 

)  const 
Initialize function for a general vector. The length of the vector is equal to the total number of degrees in the DoFHandler. If the vector is of class LinearAlgebra::distributed::Vector<Number>, the ghost entries are set accordingly. For vectorvalued problems with several DoFHandlers underlying this class, the parameter vector_component
defines which component is to be used.
For the vectors used with MatrixFree and in FEEvaluation, a vector needs to hold all locally active DoFs and also some of the locally relevant DoFs. The selection of DoFs is such that one can read all degrees of freedom on all locally relevant elements (locally active) plus the degrees of freedom that constraints expand into from the locally owned cells. However, not all locally relevant DoFs are stored because most of them would never be accessed in matrixvector products and result in too much data sent around which impacts the performance.
void MatrixFree< dim, Number, VectorizedArrayType >::initialize_dof_vector  (  LinearAlgebra::distributed::Vector< Number2 > &  vec, 
const unsigned int  dof_handler_index = 0 

)  const 
Initialize function for a distributed vector. The length of the vector is equal to the total number of degrees in the DoFHandler. If the vector is of class LinearAlgebra::distributed::Vector<Number>, the ghost entries are set accordingly. For vectorvalued problems with several DoFHandlers underlying this class, the parameter vector_component
defines which component is to be used.
For the vectors used with MatrixFree and in FEEvaluation, a vector needs to hold all locally active DoFs and also some of the locally relevant DoFs. The selection of DoFs is such that one can read all degrees of freedom on all locally relevant elements (locally active) plus the degrees of freedom that constraints expand into from the locally owned cells. However, not all locally relevant DoFs are stored because most of them would never be accessed in matrixvector products and result in too much data sent around which impacts the performance.
const std::shared_ptr<const Utilities::MPI::Partitioner>& MatrixFree< dim, Number, VectorizedArrayType >::get_vector_partitioner  (  const unsigned int  dof_handler_index = 0  )  const 
Return the partitioner that represents the locally owned data and the ghost indices where access is needed to for the cell loop. The partitioner is constructed from the locally owned dofs and ghost dofs given by the respective fields. If you want to have specific information about these objects, you can query them with the respective access functions. If you just want to initialize a (parallel) vector, you should usually prefer this data structure as the data exchange information can be reused from one vector to another.
const IndexSet& MatrixFree< dim, Number, VectorizedArrayType >::get_locally_owned_set  (  const unsigned int  dof_handler_index = 0  )  const 
Return the set of cells that are oned by the processor.
const IndexSet& MatrixFree< dim, Number, VectorizedArrayType >::get_ghost_set  (  const unsigned int  dof_handler_index = 0  )  const 
Return the set of ghost cells needed but not owned by the processor.
const std::vector<unsigned int>& MatrixFree< dim, Number, VectorizedArrayType >::get_constrained_dofs  (  const unsigned int  dof_handler_index = 0  )  const 
Return a list of all degrees of freedom that are constrained. The list is returned in MPIlocal index space for the locally owned range of the vector, not in global MPI index space that spans all MPI processors. To get numbers in global index space, call get_vector_partitioner()>local_to_global
on an entry of the vector. In addition, it only returns the indices for degrees of freedom that are owned locally, not for ghosts.
void MatrixFree< dim, Number, VectorizedArrayType >::renumber_dofs  (  std::vector< types::global_dof_index > &  renumbering, 
const unsigned int  dof_handler_index = 0 

) 
Computes a renumbering of degrees of freedom that better fits with the data layout in MatrixFree according to the given layout of data. Note that this function does not rearrange the information stored in this class, but rather creates a renumbering for consumption of DoFHandler::renumber_dofs. To have any effect a MatrixFree object must be set up again using the renumbered DoFHandler and AffineConstraints. Note that if a DoFHandler calls DoFHandler::renumber_dofs, all information in MatrixFree becomes invalid.

static 
Return whether a given FiniteElement fe
is supported by this class.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_components  (  )  const 
Return the number of different DoFHandlers specified at initialization.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_base_elements  (  const unsigned int  dof_handler_index  )  const 
For the finite element underlying the DoFHandler specified by dof_handler_index
, return the number of base elements.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_physical_cells  (  )  const 
Return the number of cells this structure is based on. If you are using a usual DoFHandler, it corresponds to the number of (locally owned) active cells. Note that most data structures in this class do not directly act on this number but rather on n_cell_batches() which gives the number of cells as seen when lumping several cells together with vectorization.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_macro_cells  (  )  const 
Return the number of cell batches that this structure works on. The batches are formed by application of vectorization over several cells in general. The cell range in cell_loop
runs from zero to n_cell_batches() (exclusive), so this is the appropriate size if you want to store arrays of data for all cells to be worked on. This number is approximately n_physical_cells()/VectorizedArray::n_array_elements
(depending on how many cell chunks that do not get filled up completely).
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_cell_batches  (  )  const 
Return the number of cell batches that this structure works on. The batches are formed by application of vectorization over several cells in general. The cell range in cell_loop
runs from zero to n_cell_batches() (exclusive), so this is the appropriate size if you want to store arrays of data for all cells to be worked on. This number is approximately n_physical_cells()/VectorizedArray::n_array_elements
(depending on how many cell chunks that do not get filled up completely).
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_ghost_cell_batches  (  )  const 
Return the number of additional cell batches that this structure keeps for face integration. Note that not all cells that are ghosted in the triangulation are kept in this data structure, but only the ones which are necessary for evaluating face integrals from both sides.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_inner_face_batches  (  )  const 
Return the number of interior face batches that this structure works on. The batches are formed by application of vectorization over several faces in general. The face range in loop
runs from zero to n_inner_face_batches() (exclusive), so this is the appropriate size if you want to store arrays of data for all interior faces to be worked on.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_boundary_face_batches  (  )  const 
Return the number of boundary face batches that this structure works on. The batches are formed by application of vectorization over several faces in general. The face range in loop
runs from n_inner_face_batches() to n_inner_face_batches()+n_boundary_face_batches() (exclusive), so if you need to store arrays that hold data for all boundary faces but not the interior ones, this number gives the appropriate size.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_ghost_inner_face_batches  (  )  const 
Return the number of faces that are not processed locally but belong to locally owned faces.
types::boundary_id MatrixFree< dim, Number, VectorizedArrayType >::get_boundary_id  (  const unsigned int  macro_face  )  const 
In order to apply different operators to different parts of the boundary, this method can be used to query the boundary id of a given face in the faces' own sorting by lanes in a VectorizedArray. Only valid for an index indicating a boundary face.
std::array<types::boundary_id, VectorizedArrayType::n_array_elements> MatrixFree< dim, Number, VectorizedArrayType >::get_faces_by_cells_boundary_id  (  const unsigned int  macro_cell, 
const unsigned int  face_number  
)  const 
Return the boundary ids for the faces within a cell, using the cells' sorting by lanes in the VectorizedArray.
const DoFHandlerType& MatrixFree< dim, Number, VectorizedArrayType >::get_dof_handler  (  const unsigned int  dof_handler_index = 0  )  const 
Return the DoFHandler with the index as given to the respective std::vector
argument in the reinit() function. Note that if you want to call this function with a template parameter different than the default one, you will need to use the template
before the function call, i.e., you will have something like matrix_free.template get_dof_handler<hp::DoFHandler<dim>>()
.
DoFHandler<dim>::cell_iterator MatrixFree< dim, Number, VectorizedArrayType >::get_cell_iterator  (  const unsigned int  macro_cell_number, 
const unsigned int  vector_number,  
const unsigned int  dof_handler_index = 0 

)  const 
Return the cell iterator in deal.II speak to a given cell in the renumbering of this structure.
Note that the cell iterators in deal.II go through cells differently to what the cell loop of this class does. This is because several cells are worked on together (vectorization), and since cells with neighbors on different MPI processors need to be accessed at a certain time when accessing remote data and overlapping communication with computation.
std::pair<int, int> MatrixFree< dim, Number, VectorizedArrayType >::get_cell_level_and_index  (  const unsigned int  macro_cell_number, 
const unsigned int  vector_number  
)  const 
This returns the level and index for the cell that would be returned by get_cell_iterator() for the same arguments macro_cell_number
and vector_number
.
std::pair<typename DoFHandler<dim>::cell_iterator, unsigned int> MatrixFree< dim, Number, VectorizedArrayType >::get_face_iterator  (  const unsigned int  face_batch_number, 
const unsigned int  vector_number,  
const bool  interior = true , 

const unsigned int  fe_component = 0 

)  const 
Return the cell iterator in deal.II speak to a interior/exterior cell of given face in the renumbering of this structure. The second element of the pair is the face number so that the face iterator can be accessed: pair.first()>face(pair.second() );
Note that the face iterators in deal.II go through cells differently to what the face/boundary loop of this class does. This is because several faces are worked on together (vectorization), and since faces with neighbor cells on different MPI processors need to be accessed at a certain time when accessing remote data and overlapping communication with computation.
hp::DoFHandler<dim>::active_cell_iterator MatrixFree< dim, Number, VectorizedArrayType >::get_hp_cell_iterator  (  const unsigned int  macro_cell_number, 
const unsigned int  vector_number,  
const unsigned int  dof_handler_index = 0 

)  const 
This returns the cell iterator in deal.II speak to a given cell in the renumbering of this structure. This function returns an exception in case the structure was not constructed based on an hp::DoFHandler.
Note that the cell iterators in deal.II go through cells differently to what the cell loop of this class does. This is because several cells are worked on together (vectorization), and since cells with neighbors on different MPI processors need to be accessed at a certain time when accessing remote data and overlapping communication with computation.
bool MatrixFree< dim, Number, VectorizedArrayType >::at_irregular_cell  (  const unsigned int  macro_cell_number  )  const 
Since this class uses vectorized data types with usually more than one value in the data field, a situation might occur when some components of the vector type do not correspond to an actual cell in the mesh. When using only this class, one usually does not need to bother about that fact since the values are padded with zeros. However, when this class is mixed with deal.II access to cells, care needs to be taken. This function returns true
if not all vectorization_length
cells for the given macro_cell
are real cells. To find out how many cells are actually used, use the function n_active_entries_per_cell_batch
.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_components_filled  (  const unsigned int  cell_batch_number  )  const 
This query returns how many cells over the length of vectorization data types correspond to actual cells in the mesh. For most given cell_batch_number
, this is just vectorization_length
many, but there might be one or a few meshes (where the numbers do not add up) where there are less such components filled, indicated by the function at_irregular_cell
.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_active_entries_per_cell_batch  (  const unsigned int  cell_batch_number  )  const 
This query returns how many cells over the length of vectorization data types correspond to actual cells in the mesh. For most given cell batches in n_cell_batches(), this is just vectorization_length
many, but there might be one or a few meshes (where the numbers do not add up) where there are less such components filled, indicated by the function at_irregular_cell
.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_active_entries_per_face_batch  (  const unsigned int  face_batch_number  )  const 
Use this function to find out how many faces over the length of vectorization data types correspond to real faces (both interior and boundary faces, as those use the same indexing but with different ranges) in the mesh. For most given indices in n_inner_faces_batches() and n_boundary_face_batches(), this is just vectorization_length
many, but there might be one or a few meshes (where the numbers do not add up) where there are less such lanes filled.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::get_dofs_per_cell  (  const unsigned int  dof_handler_index = 0 , 
const unsigned int  hp_active_fe_index = 0 

)  const 
Return the number of degrees of freedom per cell for a given hp index.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::get_n_q_points  (  const unsigned int  quad_index = 0 , 
const unsigned int  hp_active_fe_index = 0 

)  const 
Return the number of quadrature points per cell for a given hp index.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::get_dofs_per_face  (  const unsigned int  dof_handler_index = 0 , 
const unsigned int  hp_active_fe_index = 0 

)  const 
Return the number of degrees of freedom on each face of the cell for given hp index.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::get_n_q_points_face  (  const unsigned int  quad_index = 0 , 
const unsigned int  hp_active_fe_index = 0 

)  const 
Return the number of quadrature points on each face of the cell for given hp index.
const Quadrature<dim>& MatrixFree< dim, Number, VectorizedArrayType >::get_quadrature  (  const unsigned int  quad_index = 0 , 
const unsigned int  hp_active_fe_index = 0 

)  const 
Return the quadrature rule for given hp index.
const Quadrature<dim  1>& MatrixFree< dim, Number, VectorizedArrayType >::get_face_quadrature  (  const unsigned int  quad_index = 0 , 
const unsigned int  hp_active_fe_index = 0 

)  const 
Return the quadrature rule for given hp index.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::get_cell_category  (  const unsigned int  macro_cell  )  const 
Return the category the current batch of cells was assigned to. Categories run between the given values in the field AdditionalData::cell_vectorization_category for nonhp DoFHandler types and return the active FE index in the hpadaptive case.
std::pair<unsigned int, unsigned int> MatrixFree< dim, Number, VectorizedArrayType >::get_face_category  (  const unsigned int  macro_face  )  const 
Return the category on the cells on the two sides of the current batch of faces.
bool MatrixFree< dim, Number, VectorizedArrayType >::indices_initialized  (  )  const 
Queries whether or not the indexation has been set.
bool MatrixFree< dim, Number, VectorizedArrayType >::mapping_initialized  (  )  const 
Queries whether or not the geometryrelated information for the cells has been set.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::get_mg_level  (  )  const 
Return the level of the mesh to be worked on. Returns numbers::invalid_unsigned_int if working on active cells.
std::size_t MatrixFree< dim, Number, VectorizedArrayType >::memory_consumption  (  )  const 
Return an approximation of the memory consumption of this class in bytes.
void MatrixFree< dim, Number, VectorizedArrayType >::print_memory_consumption  (  StreamType &  out  )  const 
Prints a detailed summary of memory consumption in the different structures of this class to the given output stream.
void MatrixFree< dim, Number, VectorizedArrayType >::print  (  std::ostream &  out  )  const 
Prints a summary of this class to the given output stream. It is focused on the indices, and does not print all the data stored.
const internal::MatrixFreeFunctions::TaskInfo& MatrixFree< dim, Number, VectorizedArrayType >::get_task_info  (  )  const 
Return information on task graph.
const internal::MatrixFreeFunctions::DoFInfo& MatrixFree< dim, Number, VectorizedArrayType >::get_dof_info  (  const unsigned int  dof_handler_index_component = 0  )  const 
Return information on indexation degrees of freedom.
unsigned int MatrixFree< dim, Number, VectorizedArrayType >::n_constraint_pool_entries  (  )  const 
Return the number of weights in the constraint pool.
const Number* MatrixFree< dim, Number, VectorizedArrayType >::constraint_pool_begin  (  const unsigned int  pool_index  )  const 
Return a pointer to the first number in the constraint pool data with index pool_index
(to be used together with constraint_pool_end()
).
const Number* MatrixFree< dim, Number, VectorizedArrayType >::constraint_pool_end  (  const unsigned int  pool_index  )  const 
Return a pointer to one past the last number in the constraint pool data with index pool_index
(to be used together with constraint_pool_begin()
).
const internal::MatrixFreeFunctions::ShapeInfo<VectorizedArrayType>& MatrixFree< dim, Number, VectorizedArrayType >::get_shape_info  (  const unsigned int  dof_handler_index_component = 0 , 
const unsigned int  quad_index = 0 , 

const unsigned int  fe_base_element = 0 , 

const unsigned int  hp_active_fe_index = 0 , 

const unsigned int  hp_active_quad_index = 0 

)  const 
Return the unit cell information for given hp index.
const internal::MatrixFreeFunctions::FaceToCellTopology< VectorizedArrayType::n_array_elements>& MatrixFree< dim, Number, VectorizedArrayType >::get_face_info  (  const unsigned int  face_batch_number  )  const 
Return the connectivity information of a face.
const Table<3, unsigned int>& MatrixFree< dim, Number, VectorizedArrayType >::get_cell_and_face_to_plain_faces  (  )  const 
Return the table that translates a triple of the macro cell number, the index of a face within a cell and the index within the cell batch of vectorization into the index within the faces array.
AlignedVector<VectorizedArrayType>* MatrixFree< dim, Number, VectorizedArrayType >::acquire_scratch_data  (  )  const 
Obtains a scratch data object for internal use. Make sure to release it afterwards by passing the pointer you obtain from this object to the release_scratch_data() function. This interface is used by FEEvaluation objects for storing their data structures.
The organization of the internal data structure is a threadlocal storage of a list of vectors. Multiple threads will each get a separate storage field and separate vectors, ensuring thread safety. The mechanism to acquire and release objects is similar to the mechanisms used for the local contributions of WorkStream, see the WorkStream paper.
void MatrixFree< dim, Number, VectorizedArrayType >::release_scratch_data  (  const AlignedVector< VectorizedArrayType > *  memory  )  const 
Makes the object of the scratchpad available again.
AlignedVector<Number>* MatrixFree< dim, Number, VectorizedArrayType >::acquire_scratch_data_non_threadsafe  (  )  const 
Obtains a scratch data object for internal use. Make sure to release it afterwards by passing the pointer you obtain from this object to the release_scratch_data_non_threadsafe() function. Note that, as opposed to acquire_scratch_data(), this method can only be called by a single thread at a time, but opposed to the acquire_scratch_data() it is also possible that the thread releasing the scratch data can be different than the one that acquired it.
void MatrixFree< dim, Number, VectorizedArrayType >::release_scratch_data_non_threadsafe  (  const AlignedVector< Number > *  memory  )  const 
Makes the object of the scratch data available again.

private 
This is the actual reinit function that sets up the indices for the DoFHandler case.

private 
Same as before but for hp::DoFHandler instead of generic DoFHandler type.

private 
Initializes the fields in DoFInfo together with the constraint pool that holds all different weights in the constraints (not part of DoFInfo because several DoFInfo classes can have the same weights which consequently only need to be stored once).

private 
Initializes the DoFHandlers based on a DoFHandler<dim> argument.

private 
Initializes the DoFHandlers based on a hp::DoFHandler<dim> argument.

private 
Setup connectivity graph with information on the dependencies between block due to shared faces.

related 
Compute the quadrature point index in the local cell of a given thread.
Definition at line 630 of file cuda_matrix_free.h.

related 
Return the quadrature point index local of a given thread. The index is only unique for a given MPI process.
Definition at line 650 of file cuda_matrix_free.h.

related 
Return the quadrature point associated with a given thread.
Definition at line 669 of file cuda_matrix_free.h.

static 
The dimension set by the template argument dim
.
Definition at line 134 of file matrix_free.h.

private 
Pointers to the DoFHandlers underlying the current problem.
Definition at line 2050 of file matrix_free.h.

private 
Contains the information about degrees of freedom on the individual cells and constraints.
Definition at line 2056 of file matrix_free.h.

private 
Contains the weights for constraints stored in DoFInfo. Filled into a separate field since several vector components might share similar weights, which reduces memory consumption. Moreover, it obviates template arguments on DoFInfo and keeps it a plain field of indices only.
Definition at line 2064 of file matrix_free.h.

private 
Contains an indicator to the start of the ith index in the constraint pool data.
Definition at line 2070 of file matrix_free.h.

private 
Holds information on transformation of cells from reference cell to real cell that is needed for evaluating integrals.
Definition at line 2077 of file matrix_free.h.

private 
Contains shape value information on the unit cell.
Definition at line 2083 of file matrix_free.h.

private 
Describes how the cells are gone through. With the cell level (first index in this field) and the index within the level, one can reconstruct a deal.II cell iterator and use all the traditional things deal.II offers to do with cell iterators.
Definition at line 2091 of file matrix_free.h.

private 
For discontinuous Galerkin, the cell_level_index includes cells that are not on the local processor but that are needed to evaluate the cell integrals. In cell_level_index_end_local, we store the number of local cells.
Definition at line 2100 of file matrix_free.h.

private 
Stores the basic layout of the cells and faces to be treated, including the task layout for the shared memory parallelization and possible overlaps between communications and computations with MPI.
Definition at line 2107 of file matrix_free.h.

private 
Vector holding face information. Only initialized if build_face_info=true.
Definition at line 2114 of file matrix_free.h.

private 
Stores whether indices have been initialized.
Definition at line 2119 of file matrix_free.h.

private 
Stores whether indices have been initialized.
Definition at line 2124 of file matrix_free.h.

mutableprivate 
Scratchpad memory for use in evaluation. We allow more than one evaluation object to attach to this field (this, the outer std::vector), so we need to keep tracked of whether a certain data field is already used (first part of pair) and keep a list of objects.
Definition at line 2135 of file matrix_free.h.

mutableprivate 
Scratchpad memory for use in evaluation and other contexts, nonthread safe variant.
Definition at line 2142 of file matrix_free.h.

private 
Stored the level of the mesh to be worked on.
Definition at line 2147 of file matrix_free.h.