Reference documentation for deal.II version Git 409ee4b167 2020-08-14 09:46:12 -0400
LinearAlgebra::distributed::BlockVector< Number > Class Template Reference

#include <deal.II/lac/la_parallel_block_vector.h>

Inheritance diagram for LinearAlgebra::distributed::BlockVector< Number >:
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## Public Types

using BaseClass = BlockVectorBase< Vector< Number > >

using BlockType = typename BaseClass::BlockType

using value_type = typename BaseClass::value_type

using real_type = typename BaseClass::real_type

using pointer = typename BaseClass::pointer

using const_pointer = typename BaseClass::const_pointer

using reference = typename BaseClass::reference

using const_reference = typename BaseClass::const_reference

using size_type = typename BaseClass::size_type

using iterator = typename BaseClass::iterator

using const_iterator = typename BaseClass::const_iterator

Public Types inherited from BlockVectorBase< Vector< Number > >
using BlockType = Vector< Number >

using value_type = typename BlockType::value_type

using pointer = value_type *

using const_pointer = const value_type *

using iterator = ::internal::BlockVectorIterators::Iterator< BlockVectorBase, false >

using const_iterator = ::internal::BlockVectorIterators::Iterator< BlockVectorBase, true >

using reference = typename BlockType::reference

using const_reference = typename BlockType::const_reference

using size_type = types::global_dof_index

using real_type = typename BlockType::real_type

Public Types inherited from LinearAlgebra::VectorSpaceVector< Number >
using value_type = Number

using size_type = types::global_dof_index

using real_type = typename numbers::NumberTraits< Number >::real_type

## Public Member Functions

1: Basic operations
BlockVector (const size_type num_blocks=0, const size_type block_size=0)

BlockVector (const BlockVector< Number > &V)

template<typename OtherNumber >
BlockVector (const BlockVector< OtherNumber > &v)

BlockVector (const std::vector< size_type > &block_sizes)

BlockVector (const std::vector< IndexSet > &local_ranges, const std::vector< IndexSet > &ghost_indices, const MPI_Comm communicator)

BlockVector (const std::vector< IndexSet > &local_ranges, const MPI_Comm communicator)

virtual ~BlockVector () override=default

virtual BlockVectoroperator= (const value_type s) override

BlockVectoroperator= (const BlockVector &V)

template<class Number2 >
BlockVectoroperator= (const BlockVector< Number2 > &V)

BlockVectoroperator= (const Vector< Number > &V)

BlockVector< Number > & operator= (const PETScWrappers::MPI::BlockVector &petsc_vec)

BlockVector< Number > & operator= (const TrilinosWrappers::MPI::BlockVector &trilinos_vec)

void reinit (const size_type num_blocks, const size_type block_size=0, const bool omit_zeroing_entries=false)

void reinit (const std::vector< size_type > &N, const bool omit_zeroing_entries=false)

template<typename Number2 >
void reinit (const BlockVector< Number2 > &V, const bool omit_zeroing_entries=false)

virtual void compress (::VectorOperation::values operation) override

void update_ghost_values () const

void zero_out_ghosts () const

bool has_ghost_elements () const

template<typename OtherNumber >
void add (const std::vector< size_type > &indices, const ::Vector< OtherNumber > &values)

void sadd (const Number s, const BlockVector< Number > &V)

virtual bool all_zero () const override

virtual Number mean_value () const override

real_type lp_norm (const real_type p) const

void swap (BlockVector< Number > &v)

2: Implementation of VectorSpaceVector
virtual void reinit (const VectorSpaceVector< Number > &V, const bool omit_zeroing_entries=false) override

virtual BlockVector< Number > & operator*= (const Number factor) override

virtual BlockVector< Number > & operator/= (const Number factor) override

virtual BlockVector< Number > & operator+= (const VectorSpaceVector< Number > &V) override

virtual BlockVector< Number > & operator-= (const VectorSpaceVector< Number > &V) override

virtual void import (const LinearAlgebra::ReadWriteVector< Number > &V, VectorOperation::values operation, std::shared_ptr< const CommunicationPatternBase > communication_pattern=std::shared_ptr< const CommunicationPatternBase >()) override

virtual Number operator* (const VectorSpaceVector< Number > &V) const override

template<typename FullMatrixType >
void multivector_inner_product (FullMatrixType &matrix, const BlockVector< Number > &V, const bool symmetric=false) const

template<typename FullMatrixType >
Number multivector_inner_product_with_metric (const FullMatrixType &matrix, const BlockVector< Number > &V, const bool symmetric=false) const

template<typename FullMatrixType >
void mmult (BlockVector< Number > &V, const FullMatrixType &matrix, const Number s=Number(0.), const Number b=Number(1.)) const

virtual void add (const Number a) override

virtual void add (const Number a, const VectorSpaceVector< Number > &V) override

virtual void add (const Number a, const VectorSpaceVector< Number > &V, const Number b, const VectorSpaceVector< Number > &W) override

virtual void add (const std::vector< size_type > &indices, const std::vector< Number > &values)

virtual void sadd (const Number s, const Number a, const VectorSpaceVector< Number > &V) override

virtual void scale (const VectorSpaceVector< Number > &scaling_factors) override

virtual void equ (const Number a, const VectorSpaceVector< Number > &V) override

virtual real_type l1_norm () const override

virtual real_type l2_norm () const override

real_type norm_sqr () const

virtual real_type linfty_norm () const override

virtual Number add_and_dot (const Number a, const VectorSpaceVector< Number > &V, const VectorSpaceVector< Number > &W) override

virtual size_type size () const override

virtual ::IndexSet locally_owned_elements () const override

virtual void print (std::ostream &out, const unsigned int precision=3, const bool scientific=true, const bool across=true) const override

virtual std::size_t memory_consumption () const override

Public Member Functions inherited from BlockVectorBase< Vector< Number > >
BlockVectorBase ()=default

BlockVectorBase (const BlockVectorBase &)=default

BlockVectorBase (BlockVectorBase &&) noexcept=default

void collect_sizes ()

void compress (::VectorOperation::values operation)

BlockTypeblock (const unsigned int i)

const BlockTypeblock (const unsigned int i) const

const BlockIndicesget_block_indices () const

unsigned int n_blocks () const

std::size_t size () const

IndexSet locally_owned_elements () const

iterator begin ()

const_iterator begin () const

iterator end ()

const_iterator end () const

value_type operator() (const size_type i) const

reference operator() (const size_type i)

value_type operator[] (const size_type i) const

reference operator[] (const size_type i)

void extract_subvector_to (const std::vector< size_type > &indices, std::vector< OtherNumber > &values) const

void extract_subvector_to (ForwardIterator indices_begin, const ForwardIterator indices_end, OutputIterator values_begin) const

BlockVectorBaseoperator= (const value_type s)

BlockVectorBaseoperator= (const BlockVectorBase &V)

BlockVectorBaseoperator= (BlockVectorBase &&)=default

BlockVectorBaseoperator= (const BlockVectorBase< VectorType2 > &V)

BlockVectorBaseoperator= (const Vector< Number > &v)

bool operator== (const BlockVectorBase< VectorType2 > &v) const

value_type operator* (const BlockVectorBase &V) const

real_type norm_sqr () const

value_type mean_value () const

real_type l1_norm () const

real_type l2_norm () const

real_type linfty_norm () const

value_type add_and_dot (const value_type a, const BlockVectorBase &V, const BlockVectorBase &W)

bool in_local_range (const size_type global_index) const

bool all_zero () const

bool is_non_negative () const

BlockVectorBaseoperator+= (const BlockVectorBase &V)

BlockVectorBaseoperator-= (const BlockVectorBase &V)

void add (const std::vector< size_type > &indices, const std::vector< Number > &values)

void add (const std::vector< size_type > &indices, const Vector< Number > &values)

void add (const size_type n_elements, const size_type *indices, const Number *values)

void add (const value_type a, const BlockVectorBase &V)

void add (const value_type a, const BlockVectorBase &V, const value_type b, const BlockVectorBase &W)

void sadd (const value_type s, const BlockVectorBase &V)

void sadd (const value_type s, const value_type a, const BlockVectorBase &V)

void sadd (const value_type s, const value_type a, const BlockVectorBase &V, const value_type b, const BlockVectorBase &W)

void sadd (const value_type s, const value_type a, const BlockVectorBase &V, const value_type b, const BlockVectorBase &W, const value_type c, const BlockVectorBase &X)

BlockVectorBaseoperator*= (const value_type factor)

BlockVectorBaseoperator/= (const value_type factor)

void scale (const BlockVector2 &v)

void equ (const value_type a, const BlockVector2 &V)

void update_ghost_values () const

std::size_t memory_consumption () const

Public Member Functions inherited from Subscriptor
Subscriptor ()

Subscriptor (const Subscriptor &)

Subscriptor (Subscriptor &&) noexcept

virtual ~Subscriptor ()

Subscriptoroperator= (const Subscriptor &)

Subscriptoroperator= (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)

Public Member Functions inherited from LinearAlgebra::VectorSpaceVector< Number >
virtual VectorSpaceVector< Number > & operator= (const Number s)=0

virtual void compress (VectorOperation::values)

virtual ~VectorSpaceVector ()=default

## Static Public Member Functions

static ::ExceptionBaseExcVectorTypeNotCompatible ()

static ::ExceptionBaseExcIteratorRangeDoesNotMatchVectorSize ()

Static Public Member Functions inherited from Subscriptor
static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)

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

## Static Public Attributes

static constexpr unsigned int communication_block_size = 20

Protected Attributes inherited from BlockVectorBase< Vector< Number > >
std::vector< Vector< Number > > components

BlockIndices block_indices

## Detailed Description

### template<typename Number> class LinearAlgebra::distributed::BlockVector< Number >

An implementation of block vectors based on distributed deal.II vectors. While the base class provides for most of the interface, this class handles the actual allocation of vectors and provides functions that are specific to the underlying vector type.

Note
Instantiations for this template are provided for <float> and <double>; others can be generated in application programs (see the section on Template instantiations in the manual).
Block (linear algebra)

Definition at line 84 of file la_parallel_block_vector.h.

## ◆ BaseClass

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::BaseClass = BlockVectorBase >

Definition at line 105 of file la_parallel_block_vector.h.

## ◆ BlockType

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::BlockType = typename BaseClass::BlockType

Typedef the type of the underlying vector.

Definition at line 110 of file la_parallel_block_vector.h.

## ◆ value_type

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::value_type = typename BaseClass::value_type

Import the alias from the base class.

Definition at line 115 of file la_parallel_block_vector.h.

## ◆ real_type

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::real_type = typename BaseClass::real_type

Definition at line 116 of file la_parallel_block_vector.h.

## ◆ pointer

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::pointer = typename BaseClass::pointer

Definition at line 117 of file la_parallel_block_vector.h.

## ◆ const_pointer

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::const_pointer = typename BaseClass::const_pointer

Definition at line 118 of file la_parallel_block_vector.h.

## ◆ reference

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::reference = typename BaseClass::reference

Definition at line 119 of file la_parallel_block_vector.h.

## ◆ const_reference

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::const_reference = typename BaseClass::const_reference

Definition at line 120 of file la_parallel_block_vector.h.

## ◆ size_type

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::size_type = typename BaseClass::size_type

Definition at line 121 of file la_parallel_block_vector.h.

## ◆ iterator

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::iterator = typename BaseClass::iterator

Definition at line 122 of file la_parallel_block_vector.h.

## ◆ const_iterator

template<typename Number>
 using LinearAlgebra::distributed::BlockVector< Number >::const_iterator = typename BaseClass::const_iterator

Definition at line 123 of file la_parallel_block_vector.h.

## ◆ BlockVector() [1/6]

template<typename Number>
 LinearAlgebra::distributed::BlockVector< Number >::BlockVector ( const size_type num_blocks = 0, const size_type block_size = 0 )
explicit

Constructor. There are three ways to use this constructor. First, without any arguments, it generates an object with no blocks. Given one argument, it initializes num_blocks blocks, but these blocks have size zero. The third variant finally initializes all blocks to the same size block_size.

Confer the other constructor further down if you intend to use blocks of different sizes.

## ◆ BlockVector() [2/6]

template<typename Number>
 LinearAlgebra::distributed::BlockVector< Number >::BlockVector ( const BlockVector< Number > & V )

Copy-Constructor. Dimension set to that of V, all components are copied from V

## ◆ BlockVector() [3/6]

template<typename Number>
template<typename OtherNumber >
 LinearAlgebra::distributed::BlockVector< Number >::BlockVector ( const BlockVector< OtherNumber > & v )
explicit

Copy constructor taking a BlockVector of another data type. This will fail if there is no conversion path from OtherNumber to Number. Note that you may lose accuracy when copying to a BlockVector with data elements with less accuracy.

Older versions of gcc did not honor the explicit keyword on template constructors. In such cases, it is easy to accidentally write code that can be very inefficient, since the compiler starts performing hidden conversions. To avoid this, this function is disabled if we have detected a broken compiler during configuration.

## ◆ BlockVector() [4/6]

template<typename Number>
 LinearAlgebra::distributed::BlockVector< Number >::BlockVector ( const std::vector< size_type > & block_sizes )

Constructor. Set the number of blocks to block_sizes.size() and initialize each block with block_sizes[i] zero elements.

## ◆ BlockVector() [5/6]

template<typename Number>
 LinearAlgebra::distributed::BlockVector< Number >::BlockVector ( const std::vector< IndexSet > & local_ranges, const std::vector< IndexSet > & ghost_indices, const MPI_Comm communicator )

Construct a block vector with an IndexSet for the local range and ghost entries for each block.

## ◆ BlockVector() [6/6]

template<typename Number>
 LinearAlgebra::distributed::BlockVector< Number >::BlockVector ( const std::vector< IndexSet > & local_ranges, const MPI_Comm communicator )

Same as above but the ghost indices are assumed to be empty.

## ◆ ~BlockVector()

template<typename Number>
 virtual LinearAlgebra::distributed::BlockVector< Number >::~BlockVector ( )
overridevirtualdefault

Destructor.

Note
We need to explicitly provide a destructor, otherwise the linker may think it is unused and discards it, although required in a different section. The Intel compiler is prone to this behavior.

## ◆ operator=() [1/6]

template<typename Number>
 virtual BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator= ( const value_type s )
overridevirtual

Copy operator: fill all components of the vector with the given scalar value.

## ◆ operator=() [2/6]

template<typename Number>
 BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator= ( const BlockVector< Number > & V )

Copy operator for arguments of the same type. Resize the present vector if necessary.

## ◆ operator=() [3/6]

template<typename Number>
template<class Number2 >
 BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator= ( const BlockVector< Number2 > & V )

Copy operator for template arguments of different types. Resize the present vector if necessary.

## ◆ operator=() [4/6]

template<typename Number>
 BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator= ( const Vector< Number > & V )

Copy a regular vector into a block vector.

## ◆ operator=() [5/6]

template<typename Number>
 BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator= ( const PETScWrappers::MPI::BlockVector< Number > & petsc_vec )

Copy the content of a PETSc vector into the calling vector. This function assumes that the vectors layouts have already been initialized to match.

This operator is only available if deal.II was configured with PETSc.

## ◆ operator=() [6/6]

template<typename Number>
 BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator= ( const TrilinosWrappers::MPI::BlockVector< Number > & trilinos_vec )

Copy the content of a Trilinos vector into the calling vector. This function assumes that the vectors layouts have already been initialized to match.

This operator is only available if deal.II was configured with Trilinos.

## ◆ reinit() [1/4]

template<typename Number>
 void LinearAlgebra::distributed::BlockVector< Number >::reinit ( const size_type num_blocks, const size_type block_size = 0, const bool omit_zeroing_entries = false )

Reinitialize the BlockVector to contain num_blocks blocks of size block_size each.

If the second argument is left at its default value, then the block vector allocates the specified number of blocks but leaves them at zero size. You then need to later reinitialize the individual blocks, and call collect_sizes() to update the block system's knowledge of its individual block's sizes.

If omit_zeroing_entries==false, the vector is filled with zeros.

## ◆ reinit() [2/4]

template<typename Number>
 void LinearAlgebra::distributed::BlockVector< Number >::reinit ( const std::vector< size_type > & N, const bool omit_zeroing_entries = false )

Reinitialize the BlockVector such that it contains block_sizes.size() blocks. Each block is reinitialized to dimension block_sizes[i].

If the number of blocks is the same as before this function was called, all vectors remain the same and reinit() is called for each vector.

If omit_zeroing_entries==false, the vector is filled with zeros.

Note that you must call this (or the other reinit() functions) function, rather than calling the reinit() functions of an individual block, to allow the block vector to update its caches of vector sizes. If you call reinit() on one of the blocks, then subsequent actions on this object may yield unpredictable results since they may be routed to the wrong block.

## ◆ reinit() [3/4]

template<typename Number>
template<typename Number2 >
 void LinearAlgebra::distributed::BlockVector< Number >::reinit ( const BlockVector< Number2 > & V, const bool omit_zeroing_entries = false )

Change the dimension to that of the vector V. The same applies as for the other reinit() function.

The elements of V are not copied, i.e. this function is the same as calling reinit (V.size(), omit_zeroing_entries).

Note that you must call this (or the other reinit() functions) function, rather than calling the reinit() functions of an individual block, to allow the block vector to update its caches of vector sizes. If you call reinit() of one of the blocks, then subsequent actions of this object may yield unpredictable results since they may be routed to the wrong block.

## ◆ compress()

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::compress ( ::VectorOperation::values operation )
overridevirtual

This function copies the data that has accumulated in the data buffer for ghost indices to the owning processor. For the meaning of the argument operation, see the entry on Compressing distributed vectors and matrices in the glossary.

There are two variants for this function. If called with argument VectorOperation::add adds all the data accumulated in ghost elements to the respective elements on the owning processor and clears the ghost array afterwards. If called with argument VectorOperation::insert, a set operation is performed. Since setting elements in a vector with ghost elements is ambiguous (as one can set both the element on the ghost site as well as the owning site), this operation makes the assumption that all data is set correctly on the owning processor. Upon call of compress(VectorOperation::insert), all ghost entries are therefore simply zeroed out (using zero_ghost_values()). In debug mode, a check is performed that makes sure that the data set is actually consistent between processors, i.e., whenever a non-zero ghost element is found, it is compared to the value on the owning processor and an exception is thrown if these elements do not agree.

## ◆ update_ghost_values()

template<typename Number>
 void LinearAlgebra::distributed::BlockVector< Number >::update_ghost_values ( ) const

Fills the data field for ghost indices with the values stored in the respective positions of the owning processor. This function is needed before reading from ghosts. The function is const even though ghost data is changed. This is needed to allow functions with a const vector to perform the data exchange without creating temporaries.

## ◆ zero_out_ghosts()

template<typename Number>
 void LinearAlgebra::distributed::BlockVector< Number >::zero_out_ghosts ( ) const

This method zeros the entries on ghost dofs, but does not touch locally owned DoFs.

After calling this method, read access to ghost elements of the vector is forbidden and an exception is thrown. Only write access to ghost elements is allowed in this state.

## ◆ has_ghost_elements()

template<typename Number>
 bool LinearAlgebra::distributed::BlockVector< Number >::has_ghost_elements ( ) const

Return if this Vector contains ghost elements.

template<typename Number>
template<typename OtherNumber >
 void LinearAlgebra::distributed::BlockVector< Number >::add ( const std::vector< size_type > & indices, const ::Vector< OtherNumber > & values )

This is a collective add operation that adds a whole set of values stored in values to the vector components specified by indices.

template<typename Number>
 void LinearAlgebra::distributed::BlockVector< Number >::sadd ( const Number s, const BlockVector< Number > & V )

Scaling and simple vector addition, i.e. *this = s*(*this)+V.

## ◆ all_zero()

template<typename Number>
 virtual bool LinearAlgebra::distributed::BlockVector< Number >::all_zero ( ) const
overridevirtual

Return whether the vector contains only elements with value zero. This function is mainly for internal consistency checks and should seldom be used when not in debug mode since it uses quite some time.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ mean_value()

template<typename Number>
 virtual Number LinearAlgebra::distributed::BlockVector< Number >::mean_value ( ) const
overridevirtual

Compute the mean value of all the entries in the vector.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ lp_norm()

template<typename Number>
 real_type LinearAlgebra::distributed::BlockVector< Number >::lp_norm ( const real_type p ) const

$$l_p$$-norm of the vector. The pth root of the sum of the pth powers of the absolute values of the elements.

## ◆ swap()

template<typename Number>
 void LinearAlgebra::distributed::BlockVector< Number >::swap ( BlockVector< Number > & v )

Swap the contents of this vector and the other vector v. One could do this operation with a temporary variable and copying over the data elements, but this function is significantly more efficient since it only swaps the pointers to the data of the two vectors and therefore does not need to allocate temporary storage and move data around.

Limitation: right now this function only works if both vectors have the same number of blocks. If needed, the numbers of blocks should be exchanged, too.

This function is analogous to the swap() function of all C++ standard containers. Also, there is a global function swap(u,v) that simply calls u.swap(v), again in analogy to standard functions.

## ◆ reinit() [4/4]

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::reinit ( const VectorSpaceVector< Number > & V, const bool omit_zeroing_entries = false )
overridevirtual

Change the dimension to that of the vector V. The elements of V are not copied.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ operator*=()

template<typename Number>
 virtual BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator*= ( const Number factor )
overridevirtual

Multiply the entire vector by a fixed factor.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ operator/=()

template<typename Number>
 virtual BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator/= ( const Number factor )
overridevirtual

Divide the entire vector by a fixed factor.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ operator+=()

template<typename Number>
 virtual BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator+= ( const VectorSpaceVector< Number > & V )
overridevirtual

Add the vector V to the present one.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ operator-=()

template<typename Number>
 virtual BlockVector& LinearAlgebra::distributed::BlockVector< Number >::operator-= ( const VectorSpaceVector< Number > & V )
overridevirtual

Subtract the vector V from the present one.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ import()

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::import ( const LinearAlgebra::ReadWriteVector< Number > & V, VectorOperation::values operation, std::shared_ptr< const CommunicationPatternBase > communication_pattern = std::shared_ptr< const CommunicationPatternBase >() )
overridevirtual

Import all the elements present in the vector's IndexSet from the input vector V. VectorOperation::values operation is used to decide if the elements in V should be added to the current vector or replace the current elements. The last parameter can be used if the same communication pattern is used multiple times. This can be used to improve performance.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ operator*()

template<typename Number>
 virtual Number LinearAlgebra::distributed::BlockVector< Number >::operator* ( const VectorSpaceVector< Number > & V ) const
overridevirtual

Return the scalar product of two vectors.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ multivector_inner_product()

template<typename Number>
template<typename FullMatrixType >
 void LinearAlgebra::distributed::BlockVector< Number >::multivector_inner_product ( FullMatrixType & matrix, const BlockVector< Number > & V, const bool symmetric = false ) const

Calculate the scalar product between each block of this vector and V and store the result in a full matrix matrix. This function computes the result by forming $$A_{ij}=U_i \cdot V_j$$ where $$U_i$$ and $$V_j$$ indicate the $$i$$th block (not element!) of $$U$$ and the $$j$$th block of $$V$$, respectively. If symmetric is true, it is assumed that inner product results in a square symmetric matrix and almost half of the scalar products can be avoided.

Obviously, this function can only be used if all blocks of both vectors are of the same size.

Note
Internally, a single global reduction will be called to accumulate scalar product between locally owned degrees of freedom.

## ◆ multivector_inner_product_with_metric()

template<typename Number>
template<typename FullMatrixType >
 Number LinearAlgebra::distributed::BlockVector< Number >::multivector_inner_product_with_metric ( const FullMatrixType & matrix, const BlockVector< Number > & V, const bool symmetric = false ) const

Calculate the scalar product between each block of this vector and V using a metric tensor matrix. This function computes the result of $$\sum_{ij} A^{ij} U_i \cdot V_j$$ where $$U_i$$ and $$V_j$$ indicate the $$i$$th block (not element) of $$U$$ and the $$j$$th block of $$V$$, respectively. If symmetric is true, it is assumed that $$U_i \cdot V_j$$ and $$A^{ij}$$ are symmetric matrices and almost half of the scalar products can be avoided.

Obviously, this function can only be used if all blocks of both vectors are of the same size.

Note
Internally, a single global reduction will be called to accumulate the scalar product between locally owned degrees of freedom.

## ◆ mmult()

template<typename Number>
template<typename FullMatrixType >
 void LinearAlgebra::distributed::BlockVector< Number >::mmult ( BlockVector< Number > & V, const FullMatrixType & matrix, const Number s = Number(0.), const Number b = Number(1.) ) const

Set each block of this vector as follows: $$V^i = s V^i + b \sum_{j} U_j A^{ji}$$ where $$V^i$$ and $$U_j$$ indicate the $$i$$th block (not element) of $$V$$ and the $$j$$th block of $$U$$, respectively.

Obviously, this function can only be used if all blocks of both vectors are of the same size.

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::add ( const Number a )
overridevirtual

Add a to all components. Note that a is a scalar not a vector.

Implements LinearAlgebra::VectorSpaceVector< Number >.

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::add ( const Number a, const VectorSpaceVector< Number > & V )
overridevirtual

Simple addition of a multiple of a vector, i.e. *this += a*V.

Implements LinearAlgebra::VectorSpaceVector< Number >.

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::add ( const Number a, const VectorSpaceVector< Number > & V, const Number b, const VectorSpaceVector< Number > & W )
overridevirtual

Multiple addition of scaled vectors, i.e. *this += a*V+b*W.

Implements LinearAlgebra::VectorSpaceVector< Number >.

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::add ( const std::vector< size_type > & indices, const std::vector< Number > & values )
virtual

A collective add operation: This function adds a whole set of values stored in values to the vector components specified by indices.

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::sadd ( const Number s, const Number a, const VectorSpaceVector< Number > & V )
overridevirtual

Scaling and simple addition of a multiple of a vector, i.e. *this = s*(*this)+a*V.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ scale()

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::scale ( const VectorSpaceVector< Number > & scaling_factors )
overridevirtual

Scale each element of this vector by the corresponding element in the argument. This function is mostly meant to simulate multiplication (and immediate re-assignment) by a diagonal scaling matrix.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ equ()

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::equ ( const Number a, const VectorSpaceVector< Number > & V )
overridevirtual

Assignment *this = a*V.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ l1_norm()

template<typename Number>
 virtual real_type LinearAlgebra::distributed::BlockVector< Number >::l1_norm ( ) const
overridevirtual

Return the l1 norm of the vector (i.e., the sum of the absolute values of all entries among all processors).

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ l2_norm()

template<typename Number>
 virtual real_type LinearAlgebra::distributed::BlockVector< Number >::l2_norm ( ) const
overridevirtual

Return the $$l_2$$ norm of the vector (i.e., the square root of the sum of the square of all entries among all processors).

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ norm_sqr()

template<typename Number>
 real_type LinearAlgebra::distributed::BlockVector< Number >::norm_sqr ( ) const

Return the square of the $$l_2$$ norm of the vector.

## ◆ linfty_norm()

template<typename Number>
 virtual real_type LinearAlgebra::distributed::BlockVector< Number >::linfty_norm ( ) const
overridevirtual

Return the maximum norm of the vector (i.e., the maximum absolute value among all entries and among all processors).

Implements LinearAlgebra::VectorSpaceVector< Number >.

template<typename Number>
 virtual Number LinearAlgebra::distributed::BlockVector< Number >::add_and_dot ( const Number a, const VectorSpaceVector< Number > & V, const VectorSpaceVector< Number > & W )
overridevirtual

Perform a combined operation of a vector addition and a subsequent inner product, returning the value of the inner product. In other words, the result of this function is the same as if the user called

return_value = *this * W;

The reason this function exists is that this operation involves less memory transfer than calling the two functions separately. This method only needs to load three vectors, this, V, W, whereas calling separate methods means to load the calling vector this twice. Since most vector operations are memory transfer limited, this reduces the time by 25% (or 50% if W equals this).

For complex-valued vectors, the scalar product in the second step is implemented as $$\left<v,w\right>=\sum_i v_i \bar{w_i}$$.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ size()

template<typename Number>
 virtual size_type LinearAlgebra::distributed::BlockVector< Number >::size ( ) const
overridevirtual

Return the global size of the vector, equal to the sum of the number of locally owned indices among all processors.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ locally_owned_elements()

template<typename Number>
 virtual ::IndexSet LinearAlgebra::distributed::BlockVector< Number >::locally_owned_elements ( ) const
overridevirtual

Return an index set that describes which elements of this vector are owned by the current processor. As a consequence, the index sets returned on different processors if this is a distributed vector will form disjoint sets that add up to the complete index set. Obviously, if a vector is created on only one processor, then the result would satisfy

vec.locally_owned_elements() == complete_index_set(vec.size())

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ print()

template<typename Number>
 virtual void LinearAlgebra::distributed::BlockVector< Number >::print ( std::ostream & out, const unsigned int precision = 3, const bool scientific = true, const bool across = true ) const
overridevirtual

Print the vector to the output stream out.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ memory_consumption()

template<typename Number>
 virtual std::size_t LinearAlgebra::distributed::BlockVector< Number >::memory_consumption ( ) const
overridevirtual

Return the memory consumption of this class in bytes.

Implements LinearAlgebra::VectorSpaceVector< Number >.

## ◆ communication_block_size

template<typename Number>
 constexpr unsigned int LinearAlgebra::distributed::BlockVector< Number >::communication_block_size = 20
static

The chunks size to split communication in update_ghost_values() and compress() calls.

Most common MPI implementations will get slow when too many messages/requests are outstanding. Even when messages are small, say 1 kB only, we should collect enough data with communication_block_size to cover typical infiniband latencies which are around a few microseconds. Sending 20 kB at a throughput of 5 GB/s takes 4 microseconds, so we should arrive at the bandwidth dominated regime then which is good enough.

Definition at line 100 of file la_parallel_block_vector.h.

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