Reference documentation for deal.II version 9.4.1
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BlockInfo Class Reference

A small class collecting the different BlockIndices involved in global, multilevel and local computations. More...

#include <deal.II/dofs/block_info.h>

Inheritance diagram for BlockInfo:
[legend]

## Public Member Functions

template<int dim, int spacedim>
void initialize (const DoFHandler< dim, spacedim > &, bool levels_only=false, bool active_only=false)
Fill the object with values describing block structure of the DoFHandler. More...

template<int dim, int spacedim>
void initialize_local (const DoFHandler< dim, spacedim > &)
Initialize block structure on cells and compute renumbering between cell dofs and block cell dofs. More...

const BlockIndicesglobal () const

const BlockIndiceslocal () const

const BlockIndiceslevel (unsigned int level) const

types::global_dof_index renumber (const unsigned int i) const

unsigned int n_base_elements () const

unsigned int base_element (const unsigned int i) const

template<class OS >
void print (OS &stream) const

std::size_t memory_consumption () const

template<class Archive >
void serialize (Archive &ar, const unsigned int)

## Private Attributes

BlockIndices bi_global
The block structure of the global system. More...

std::vector< BlockIndiceslevels
The multilevel block structure. More...

BlockIndices bi_local
The block structure of the cell systems. More...

std::vector< unsigned intbase_elements

std::vector< types::global_dof_indexlocal_renumbering

## Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

std::atomic< unsigned intcounter

std::map< std::string, unsigned intcounter_map

std::vector< std::atomic< bool > * > validity_pointers

const std::type_info * object_info

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

using map_value_type = decltype(counter_map)::value_type

using map_iterator = decltype(counter_map)::iterator

static std::mutex mutex

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)

void check_no_subscribers () const noexcept

## Detailed Description

A small class collecting the different BlockIndices involved in global, multilevel and local computations.

Once a DoFHandler has been initialized with an FESystem, a data object of type BlockInfo (accessed by DoFHandler::block_info() ) is filled, which reflects the block structure of the degrees of freedom.

BlockInfo consists of several BlockIndices objects. The member global() reflects the block structure of the system on the active cell level, usually referred to as the global system. As soon as DoFHandler::distribute_dofs() has been called, the function BlockIndices::block_size() in global() will return the correct sizes of each block. After DoFRenumbering::block_wise(), BlockIndices::block_start() will return the start index for each of the blocks.

When a DoFHandler with levels is used, the same structure is automatically generated for each level. The level blocks can be accessed through level().

Finally, there are local() BlockIndices, which describe the block structure on a single cell. This is used for instance by MeshWorker::Assembler::MatrixLocalBlocksToGlobalBlocks. The local indices are not filled automatically, since they change the behavior of the MeshWorker::Assembler classes relying on BlockInfo. They must be initialized by hand through initialize_local().

### Usage

The most common usage for this object is initializing vectors as in the following code:

dof_handler.distribute_dofs(fe_system);
dof_handler.distribute_mg_dofs(fe_system);
BlockVector<double> solution(dof_handler.block_info().global());
MGLevelObject<BlockVector<double> > mg_vector(0, triangulation.n_levels()-1);
for (unsigned int i = 0; i < triangulation.n_levels(); ++i)
{
mg_vector[i].reinit(dof_handler.block_info().level(i));
}
void block_wise(DoFHandler< dim, spacedim > &dof_handler)
const ::parallel::distributed::Triangulation< dim, spacedim > * triangulation

In this example, solution obtains the block structure needed to represent a finite element function on the DoFHandler. Similarly, all levels of mg_vector will have the block structure needed on that level.

Todo:
Extend the functions local() and renumber() to allow for hp-capablilites.

Definition at line 93 of file block_info.h.

## ◆ initialize()

template<int dim, int spacedim>
 void BlockInfo::initialize ( const DoFHandler< dim, spacedim > & dof, bool levels_only = false, bool active_only = false )

Fill the object with values describing block structure of the DoFHandler.

By default, this function will attempt to initialize whatever is possible. If active dofs have been assigned int the DoFHandler argument, they BlockIndices for those will be generated. The same for level dofs.

This default behavior can be overridden by the two parameters, which can switch off active dofs or level dofs.

This function will also clear the local() indices.

Definition at line 30 of file block_info.cc.

## ◆ initialize_local()

template<int dim, int spacedim>
 void BlockInfo::initialize_local ( const DoFHandler< dim, spacedim > & dof )

Initialize block structure on cells and compute renumbering between cell dofs and block cell dofs.

Definition at line 62 of file block_info.cc.

## ◆ global()

 const BlockIndices & BlockInfo::global ( ) const
inline

Access the BlockIndices structure of the global system.

Definition at line 220 of file block_info.h.

## ◆ local()

 const BlockIndices & BlockInfo::local ( ) const
inline

Access BlockIndices for the local system on a cell.

Definition at line 227 of file block_info.h.

## ◆ level()

 const BlockIndices & BlockInfo::level ( unsigned int level ) const
inline

Access the BlockIndices structure of a level in the multilevel hierarchy.

Definition at line 234 of file block_info.h.

## ◆ renumber()

 types::global_dof_index BlockInfo::renumber ( const unsigned int i ) const
inline

Return the index after local renumbering.

The input of this function is an index between zero and the number of dofs per cell, numbered in local block ordering, that is first all indices of the first system block, then all of the second block and so forth. The function then outputs the index in the standard local numbering of DoFAccessor.

Definition at line 242 of file block_info.h.

## ◆ n_base_elements()

 unsigned int BlockInfo::n_base_elements ( ) const
inline

The number of base elements.

Definition at line 259 of file block_info.h.

## ◆ base_element()

 unsigned int BlockInfo::base_element ( const unsigned int i ) const
inline

Return the base element of this index.

Definition at line 250 of file block_info.h.

## ◆ print()

template<class OS >
 void BlockInfo::print ( OS & stream ) const
inline

Write a summary of the block structure to the stream.

Definition at line 268 of file block_info.h.

## ◆ memory_consumption()

 std::size_t BlockInfo::memory_consumption ( ) const
inline

Determine an estimate for the memory consumption (in bytes) of this object.

Definition at line 300 of file block_info.h.

## ◆ serialize()

template<class Archive >
 void BlockInfo::serialize ( Archive & ar, const unsigned int )

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

Definition at line 311 of file block_info.h.

## ◆ bi_global

 BlockIndices BlockInfo::bi_global
private

The block structure of the global system.

Definition at line 192 of file block_info.h.

## ◆ levels

 std::vector BlockInfo::levels
private

The multilevel block structure.

Definition at line 196 of file block_info.h.

## ◆ bi_local

 BlockIndices BlockInfo::bi_local
private

The block structure of the cell systems.

Definition at line 201 of file block_info.h.

## ◆ base_elements

 std::vector BlockInfo::base_elements
private

The base element associated with each block.

Definition at line 206 of file block_info.h.

## ◆ local_renumbering

 std::vector BlockInfo::local_renumbering
private

A vector containing the renumbering from the standard order of degrees of freedom on a cell to a component wise ordering. Filled by initialize().

Definition at line 212 of file block_info.h.

The documentation for this class was generated from the following files: