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

Inheritance diagram for PETScWrappers::MPI::Vector:

Public Types
using	size_type = types::global_dof_index

using	value_type = PetscScalar

using	real_type = PetscReal

using	reference = internal::VectorReference

using	const_reference = const internal::VectorReference

Public Member Functions
	Vector ()

	Vector (const MPI_Comm communicator, const size_type n, const size_type locally_owned_size)

template<typename Number >
	Vector (const MPI_Comm communicator, const ::Vector< Number > &v, const size_type locally_owned_size)

	Vector (const IndexSet &local, const IndexSet &ghost, const MPI_Comm communicator)

	Vector (const IndexSet &local, const MPI_Comm communicator)

	Vector (const Vector &v)

virtual void	clear () override

Vector &	operator= (const Vector &v)

Vector &	operator= (const PetscScalar s)

template<typename number >
Vector &	operator= (const ::Vector< number > &v)

void	reinit (const MPI_Comm communicator, const size_type N, const size_type locally_owned_size, const bool omit_zeroing_entries=false)

void	reinit (const Vector &v, const bool omit_zeroing_entries=false)

void	reinit (const IndexSet &local, const IndexSet &ghost, const MPI_Comm communicator)

void	reinit (const IndexSet &local, const MPI_Comm communicator)

void	reinit (const std::shared_ptr< const Utilities::MPI::Partitioner > &partitioner, const bool make_ghosted=true)

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

bool	all_zero () const

	VectorBase ()

	VectorBase (const VectorBase &v)

	VectorBase (const Vec &v)

void	reinit (Vec v)

void	compress (const VectorOperation::values operation)

bool	operator== (const VectorBase &v) const

bool	operator!= (const VectorBase &v) const

size_type	size () const

size_type	local_size () const

size_type	locally_owned_size () const

std::pair< size_type, size_type >	local_range () const

bool	in_local_range (const size_type index) const

IndexSet	locally_owned_elements () const

bool	has_ghost_elements () const

const IndexSet &	ghost_elements () const

void	update_ghost_values () const

reference	operator() (const size_type index)

PetscScalar	operator() (const size_type index) const

reference	operator[] (const size_type index)

PetscScalar	operator[] (const size_type index) const

void	set (const std::vector< size_type > &indices, const std::vector< PetscScalar > &values)

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

template<typename ForwardIterator , typename OutputIterator >
void	extract_subvector_to (const ForwardIterator indices_begin, const ForwardIterator indices_end, OutputIterator values_begin) const

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

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

void	add (const size_type n_elements, const size_type indices, const PetscScalar values)

void	add (const PetscScalar s)

void	add (const PetscScalar a, const VectorBase &V)

void	add (const PetscScalar a, const VectorBase &V, const PetscScalar b, const VectorBase &W)

PetscScalar	operator* (const VectorBase &vec) const

real_type	norm_sqr () const

PetscScalar	mean_value () const

real_type	l1_norm () const

real_type	l2_norm () const

real_type	lp_norm (const real_type p) const

real_type	linfty_norm () const

PetscScalar	add_and_dot (const PetscScalar a, const VectorBase &V, const VectorBase &W)

real_type	min () const

real_type	max () const

bool	is_non_negative () const

VectorBase &	operator*= (const PetscScalar factor)

VectorBase &	operator/= (const PetscScalar factor)

VectorBase &	operator+= (const VectorBase &V)

VectorBase &	operator-= (const VectorBase &V)

void	sadd (const PetscScalar s, const VectorBase &V)

void	sadd (const PetscScalar s, const PetscScalar a, const VectorBase &V)

void	scale (const VectorBase &scaling_factors)

void	equ (const PetscScalar a, const VectorBase &V)

void	write_ascii (const PetscViewerFormat format=PETSC_VIEWER_DEFAULT)

void	swap (VectorBase &v)

	operator const Vec & () const

Vec &	petsc_vector ()

std::size_t	memory_consumption () const

MPI_Comm	get_mpi_communicator () const

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

Subscriptor functionality
Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.
void	subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

void	unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

unsigned int	n_subscriptions () const

template<typename StreamType >
void	list_subscribers (StreamType &stream) const

void	list_subscribers () const

Static Public Member Functions
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Protected Member Functions
virtual void	create_vector (const MPI_Comm comm, const size_type n, const size_type locally_owned_size)

virtual void	create_vector (const MPI_Comm comm, const size_type n, const size_type locally_owned_size, const IndexSet &ghostnodes)

void	do_set_add_operation (const size_type n_elements, const size_type indices, const PetscScalar values, const bool add_values)

void	determine_ghost_indices ()

Protected Attributes
Vec	vector

bool	ghosted

IndexSet	ghost_indices

VectorOperation::values	last_action

Private Types
using	map_value_type = decltype(counter_map)::value_type

using	map_iterator = decltype(counter_map)::iterator

Private Member Functions
void	check_no_subscribers () const noexcept

Private Attributes
std::atomic< unsigned int >	counter

std::map< std::string, unsigned int >	counter_map

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

const std::type_info *	object_info

Static Private Attributes
static std::mutex	mutex

Related Symbols
(Note that these are not member symbols.)
void	swap (Vector &u, Vector &v)

void	swap (VectorBase &u, VectorBase &v)

Detailed Description

Implementation of a parallel vector class based on PETSC and using MPI communication to synchronize distributed operations. All the functionality is actually in the base class, except for the calls to generate a parallel vector. This is possible since PETSc only works on an abstract vector type and internally distributes to functions that do the actual work depending on the actual vector type (much like using virtual functions). Only the functions creating a vector of specific type differ, and are implemented in this particular class.

Parallel communication model

The parallel functionality of PETSc is built on top of the Message Passing Interface (MPI). MPI's communication model is built on collective communications: if one process wants something from another, that other process has to be willing to accept this communication. A process cannot query data from another process by calling a remote function, without that other process expecting such a transaction. The consequence is that most of the operations in the base class of this class have to be called collectively. For example, if you want to compute the l2 norm of a parallel vector, all processes across which this vector is shared have to call the l2_norm function. If you don't do this, but instead only call the l2_norm function on one process, then the following happens: This one process will call one of the collective MPI functions and wait for all the other processes to join in on this. Since the other processes don't call this function, you will either get a time-out on the first process, or, worse, by the time the next a call to a PETSc function generates an MPI message on the other processes, you will get a cryptic message that only a subset of processes attempted a communication. These bugs can be very hard to figure out, unless you are well-acquainted with the communication model of MPI, and know which functions may generate MPI messages.

One particular case, where an MPI message may be generated unexpectedly is discussed below.

Accessing individual elements of a vector

PETSc does allow read access to individual elements of a vector, but in the distributed case only to elements that are stored locally. We implement this through calls like d=vec(i). However, if you access an element outside the locally stored range, an exception is generated.

In contrast to read access, PETSc (and the respective deal.II wrapper classes) allow to write (or add) to individual elements of vectors, even if they are stored on a different process. You can do this writing, for example, vec(i)=d or vec(i)+=d, or similar operations. There is one catch, however, that may lead to very confusing error messages: PETSc requires application programs to call the compress() function when they switch from adding, to elements to writing to elements. The reasoning is that all processes might accumulate addition operations to elements, even if multiple processes write to the same elements. By the time we call compress() the next time, all these additions are executed. However, if one process adds to an element, and another overwrites to it, the order of execution would yield non-deterministic behavior if we don't make sure that a synchronization with compress() happens in between.

In order to make sure these calls to compress() happen at the appropriate time, the deal.II wrappers keep a state variable that store which is the presently allowed operation: additions or writes. If it encounters an operation of the opposite kind, it calls compress() and flips the state. This can sometimes lead to very confusing behavior, in code that may for example look like this:

PETScWrappers::MPI::Vector vector;
...
// do some write operations on the vector
for (unsigned int i=0; i<vector.size(); ++i)
  vector(i) = i;
 
// do some additions to vector elements, but only for some elements
for (unsigned int i=0; i<vector.size(); ++i)
  if (some_condition(i) == true)
    vector(i) += 1;
 
// do another collective operation
const double norm = vector.l2_norm();

This code can run into trouble: by the time we see the first addition operation, we need to flush the overwrite buffers for the vector, and the deal.II library will do so by calling compress(). However, it will only do so for all processes that actually do an addition – if the condition is never true for one of the processes, then this one will not get to the actual compress() call, whereas all the other ones do. This gets us into trouble, since all the other processes hang in the call to flush the write buffers, while the one other process advances to the call to compute the l2 norm. At this time, you will get an error that some operation was attempted by only a subset of processes. This behavior may seem surprising, unless you know that write/addition operations on single elements may trigger this behavior.

The problem described here may be avoided by placing additional calls to compress(), or making sure that all processes do the same type of operations at the same time, for example by placing zero additions if necessary.

See also: vectors with ghost elements

Definition at line 158 of file petsc_vector.h.

Member Typedef Documentation

◆ size_type

using PETScWrappers::MPI::Vector::size_type = types::global_dof_index

Declare type for container size.

Definition at line 164 of file petsc_vector.h.

◆ value_type

using PETScWrappers::VectorBase::value_type = PetscScalar

inherited

Declare some of the standard types used in all containers. These types parallel those in the C++ standard libraries vector<...> class.

Definition at line 258 of file petsc_vector_base.h.

◆ real_type

using PETScWrappers::VectorBase::real_type = PetscReal

inherited

Definition at line 259 of file petsc_vector_base.h.

◆ reference

using PETScWrappers::VectorBase::reference = internal::VectorReference

inherited

Definition at line 261 of file petsc_vector_base.h.

◆ const_reference

using PETScWrappers::VectorBase::const_reference = const internal::VectorReference

inherited

Definition at line 262 of file petsc_vector_base.h.

◆ map_value_type

using Subscriptor::map_value_type = decltype(counter_map)::value_type

privateinherited

The data type used in counter_map.

Definition at line 230 of file subscriptor.h.

◆ map_iterator

using Subscriptor::map_iterator = decltype(counter_map)::iterator

privateinherited

The iterator type used in counter_map.

Definition at line 235 of file subscriptor.h.

Constructor & Destructor Documentation

◆ Vector() [1/6]

Vector< Number >::Vector ( )

Default constructor. Initialize the vector as empty.

Definition at line 31 of file petsc_parallel_vector.cc.

◆ Vector() [2/6]

Vector< Number >::Vector	(	const MPI_Comm	communicator,
		const size_type	n,
		const size_type	locally_owned_size
	)

explicit

Constructor. Set dimension to n and initialize all elements with zero.

locally_owned_size denotes the size of the chunk that shall be stored on the present process.

communicator denotes the MPI communicator over which the different parts of the vector shall communicate

The constructor is made explicit to avoid accidents like this: v=0;. Presumably, the user wants to set every element of the vector to zero, but instead, what happens is this call: v=Vector<number>(0);, i.e. the vector is replaced by one of length zero.

Definition at line 41 of file petsc_parallel_vector.cc.

◆ Vector() [3/6]

template<typename Number >

PETScWrappers::MPI::Vector::Vector	(	const MPI_Comm	communicator,
		const ::Vector< Number > &	v,
		const size_type	locally_owned_size
	)

explicit

Copy-constructor from deal.II vectors. Sets the dimension to that of the given vector, and copies all elements.

locally_owned_size denotes the size of the chunk that shall be stored on the present process.

communicator denotes the MPI communicator over which the different parts of the vector shall communicate

◆ Vector() [4/6]

Vector< Number >::Vector	(	const IndexSet &	local,
		const IndexSet &	ghost,
		const MPI_Comm	communicator
	)

Construct a new parallel ghosted PETSc vector from IndexSets.

Note that local must be ascending and 1:1, see IndexSet::is_ascending_and_one_to_one(). In particular, the DoFs in local need to be contiguous, meaning you can only create vectors from a DoFHandler with several finite element components if they are not reordered by component (use a PETScWrappers::BlockVector otherwise). The global size of the vector is determined by local.size(). The global indices in ghost are supplied as ghost indices so that they can be read locally.

Note that the ghost IndexSet may be empty and that any indices already contained in local are ignored during construction. That way, the ghost parameter can equal the set of locally relevant degrees of freedom, see step-32.

Note: This operation always creates a ghosted vector, which is considered read-only.

See also: vectors with ghost elements

Definition at line 50 of file petsc_parallel_vector.cc.

◆ Vector() [5/6]

Vector< Number >::Vector	(	const IndexSet &	local,
		const MPI_Comm	communicator
	)

explicit

Construct a new parallel PETSc vector without ghost elements from an IndexSet.

Note that local must be ascending and 1:1, see IndexSet::is_ascending_and_one_to_one(). In particular, the DoFs in local need to be contiguous, meaning you can only create vectors from a DoFHandler with several finite element components if they are not reordered by component (use a PETScWrappers::BlockVector otherwise).

Definition at line 86 of file petsc_parallel_vector.cc.

◆ Vector() [6/6]

Vector< Number >::Vector ( const Vector & v )

Copy constructor.

Definition at line 68 of file petsc_parallel_vector.cc.

Member Function Documentation

◆ clear()

void Vector< Number >::clear ( )

overridevirtual

Release all memory and return to a state just like after having called the default constructor.

Reimplemented from PETScWrappers::VectorBase.

Definition at line 138 of file petsc_parallel_vector.cc.

◆ operator=() [1/3]

Vector & Vector< Number >::operator= ( const Vector & v )

Copy the given vector. Resize the present vector if necessary. Also take over the MPI communicator of v.

Definition at line 96 of file petsc_parallel_vector.cc.

◆ operator=() [2/3]

Vector & PETScWrappers::MPI::Vector::operator= ( const PetscScalar s )

Set all components of the vector to the given number s. Simply pass this down to the base class, but we still need to declare this function to make the example given in the discussion about making the constructor explicit work.

◆ operator=() [3/3]

template<typename number >

Vector & PETScWrappers::MPI::Vector::operator= ( const ::Vector< number > & v )

Copy the values of a deal.II vector (as opposed to those of the PETSc vector wrapper class) into this object.

Contrary to the case of sequential vectors, this operators requires that the present vector already has the correct size, since we need to have a partition and a communicator present which we otherwise can't get from the source vector.

◆ reinit() [1/6]

void Vector< Number >::reinit	(	const MPI_Comm	communicator,
		const size_type	N,
		const size_type	locally_owned_size,
		const bool	omit_zeroing_entries = `false`
	)

Change the dimension of the vector to N. It is unspecified how resizing the vector affects the memory allocation of this object; i.e., it is not guaranteed that resizing it to a smaller size actually also reduces memory consumption, or if for efficiency the same amount of memory is used

locally_owned_size denotes how many of the N values shall be stored locally on the present process. for less data.

communicator denotes the MPI communicator henceforth to be used for this vector.

If omit_zeroing_entries is false, the vector is filled by zeros. Otherwise, the elements are left an unspecified state.

Definition at line 148 of file petsc_parallel_vector.cc.

◆ reinit() [2/6]

void Vector< Number >::reinit	(	const Vector &	v,
		const bool	omit_zeroing_entries = `false`
	)

Change the dimension to that of the vector v, and also take over the partitioning into local sizes as well as the MPI communicator. 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(), v.locally_owned_size(), omit_zeroing_entries).

Definition at line 189 of file petsc_parallel_vector.cc.

◆ reinit() [3/6]

void Vector< Number >::reinit	(	const IndexSet &	local,
		const IndexSet &	ghost,
		const MPI_Comm	communicator
	)

Reinit as a vector with ghost elements. See the constructor with same signature for more details.

See also: vectors with ghost elements

Definition at line 212 of file petsc_parallel_vector.cc.

◆ reinit() [4/6]

void Vector< Number >::reinit	(	const IndexSet &	local,
		const MPI_Comm	communicator
	)

Reinit as a vector without ghost elements. See constructor with same signature for more details.

See also: vectors with ghost elements

Definition at line 228 of file petsc_parallel_vector.cc.

◆ reinit() [5/6]

void Vector< Number >::reinit	(	const std::shared_ptr< const Utilities::MPI::Partitioner > &	partitioner,
		const bool	make_ghosted = `true`
	)

Initialize the vector given to the parallel partitioning described in partitioner.

You can decide whether your vector will contain ghost elements with make_ghosted.

Definition at line 239 of file petsc_parallel_vector.cc.

◆ print()

void Vector< Number >::print	(	std::ostream &	out,
		const unsigned int	precision = `3`,
		const bool	scientific = `true`,
		const bool	across = `true`
	)		const

Print to a stream. precision denotes the desired precision with which values shall be printed, scientific whether scientific notation shall be used. If across is true then the vector is printed in a line, while if false then the elements are printed on a separate line each.

Note: This function overloads the one in the base class to ensure that the right thing happens for parallel vectors that are distributed across processors.

Definition at line 357 of file petsc_parallel_vector.cc.

◆ all_zero()

bool Vector< Number >::all_zero ( ) const

Return whether the vector contains only elements with value zero. This is a collective operation. This function is expensive, because potentially all elements have to be checked.

Note: This function overloads the one in the base class to make this a collective operation.

Definition at line 341 of file petsc_parallel_vector.cc.

◆ create_vector() [1/2]

void Vector< Number >::create_vector	(	const MPI_Comm	comm,
		const size_type	n,
		const size_type	locally_owned_size
	)

protectedvirtual

Create a vector of length n. For this class, we create a parallel vector. n denotes the total size of the vector to be created. locally_owned_size denotes how many of these elements shall be stored locally.

Definition at line 262 of file petsc_parallel_vector.cc.

◆ create_vector() [2/2]

void Vector< Number >::create_vector	(	const MPI_Comm	comm,
		const size_type	n,
		const size_type	locally_owned_size,
		const IndexSet &	ghostnodes
	)

protectedvirtual

Create a vector of global length n, local size locally_owned_size and with the specified ghost indices. Note that you need to call update_ghost_values() before accessing those.

Definition at line 282 of file petsc_parallel_vector.cc.

◆ VectorBase() [1/3]

PETScWrappers::VectorBase::VectorBase ( )

Import VectorBase constructors, including from a PETSc Vec object.

Definition at line 268 of file petsc_vector_base.cc.

◆ VectorBase() [2/3]

PETScWrappers::VectorBase::VectorBase ( const VectorBase & v )

Import VectorBase constructors, including from a PETSc Vec object.

Definition at line 274 of file petsc_vector_base.cc.

◆ VectorBase() [3/3]

PETScWrappers::VectorBase::VectorBase ( const Vec & v )

explicit

Import VectorBase constructors, including from a PETSc Vec object.

Definition at line 280 of file petsc_vector_base.cc.

◆ reinit() [6/6]

void PETScWrappers::VectorBase::reinit ( Vec v )

This method associates the PETSc Vec to the instance of the class. This is particularly useful when performing PETSc to Deal.II operations since it allows to reuse the Deal.II VectorBase and the PETSc Vec without incurring in memory copies.

Definition at line 336 of file petsc_vector_base.cc.

◆ compress()

void PETScWrappers::VectorBase::compress ( const VectorOperation::values operation )

inherited

Compress the underlying representation of the PETSc object, i.e. flush the buffers of the vector object if it has any. This function is necessary after writing into a vector element-by-element and before anything else can be done on it.

See Compressing distributed objects for more information.

Definition at line 553 of file petsc_vector_base.cc.

◆ operator==()

bool PETScWrappers::VectorBase::operator== ( const VectorBase & v ) const

inherited

Test for equality. This function assumes that the present vector and the one to compare with have the same size already, since comparing vectors of different sizes makes not much sense anyway.

Definition at line 400 of file petsc_vector_base.cc.

◆ operator!=()

bool PETScWrappers::VectorBase::operator!= ( const VectorBase & v ) const

inherited

Test for inequality. This function assumes that the present vector and the one to compare with have the same size already, since comparing vectors of different sizes makes not much sense anyway.

Definition at line 414 of file petsc_vector_base.cc.

◆ size()

VectorBase::size_type PETScWrappers::VectorBase::size ( ) const

inherited

Return the global dimension of the vector.

Definition at line 428 of file petsc_vector_base.cc.

◆ local_size()

VectorBase::size_type PETScWrappers::VectorBase::local_size ( ) const

inherited

Return the local dimension of the vector, i.e. the number of elements stored on the present MPI process. For sequential vectors, this number is the same as size(), but for parallel vectors it may be smaller.

To figure out which elements exactly are stored locally, use local_range() or locally_owned_elements().

Deprecated:: use locally_owned_size() instead.

Definition at line 452 of file petsc_vector_base.cc.

◆ locally_owned_size()

VectorBase::size_type PETScWrappers::VectorBase::locally_owned_size ( ) const

inherited

Return the local dimension of the vector, i.e. the number of elements stored on the present MPI process. For sequential vectors, this number is the same as size(), but for parallel vectors it may be smaller.

To figure out which elements exactly are stored locally, use local_range() or locally_owned_elements().

Definition at line 440 of file petsc_vector_base.cc.

◆ local_range()

std::pair< VectorBase::size_type, VectorBase::size_type > PETScWrappers::VectorBase::local_range ( ) const

inherited

Return a pair of indices indicating which elements of this vector are stored locally. The first number is the index of the first element stored, the second the index of the one past the last one that is stored locally. If this is a sequential vector, then the result will be the pair (0,N), otherwise it will be a pair (i,i+n), where n=locally_owned_size().

Definition at line 464 of file petsc_vector_base.cc.

◆ in_local_range()

bool PETScWrappers::VectorBase::in_local_range ( const size_type index ) const

inherited

Return whether index is in the local range or not, see also local_range().

◆ locally_owned_elements()

IndexSet PETScWrappers::VectorBase::locally_owned_elements ( ) const

inherited

Return an index set that describes which elements of this vector are owned by the current processor. Note that this index set does not include elements this vector may store locally as ghost elements but that are in fact owned by another 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())

complete_index_set

IndexSet complete_index_set(const IndexSet::size_type N)

Definition index_set.h:1089

◆ has_ghost_elements()

bool PETScWrappers::VectorBase::has_ghost_elements ( ) const

inherited

Return if the vector contains ghost elements.

See also: vectors with ghost elements

◆ ghost_elements()

const IndexSet & PETScWrappers::VectorBase::ghost_elements ( ) const

inherited

Return the IndexSet of ghost elements.

◆ update_ghost_values()

void PETScWrappers::VectorBase::update_ghost_values ( ) const

inherited

Update ghosted elements.

◆ operator()() [1/2]

reference PETScWrappers::VectorBase::operator() ( const size_type index )

inherited

Provide access to a given element, both read and write.

◆ operator()() [2/2]

PetscScalar PETScWrappers::VectorBase::operator() ( const size_type index ) const

inherited

Provide read-only access to an element.

◆ operator[]() [1/2]

reference PETScWrappers::VectorBase::operator[] ( const size_type index )

inherited

Provide access to a given element, both read and write.

Exactly the same as operator().

◆ operator[]() [2/2]

PetscScalar PETScWrappers::VectorBase::operator[] ( const size_type index ) const

inherited

Provide read-only access to an element.

Exactly the same as operator().

◆ set()

void PETScWrappers::VectorBase::set	(	const std::vector< size_type > &	indices,
		const std::vector< PetscScalar > &	values
	)

inherited

A collective set operation: instead of setting individual elements of a vector, this function allows to set a whole set of elements at once. The indices of the elements to be set are stated in the first argument, the corresponding values in the second.

Definition at line 477 of file petsc_vector_base.cc.

◆ extract_subvector_to() [1/2]

void PETScWrappers::VectorBase::extract_subvector_to	(	const std::vector< size_type > &	indices,
		std::vector< PetscScalar > &	values
	)		const

inherited

Instead of getting individual elements of a vector via operator(), this function allows getting a whole set of elements at once. The indices of the elements to be read are stated in the first argument, the corresponding values are returned in the second.

If the current vector is called v, then this function is the equivalent to the code

for (unsigned int i=0; i<indices.size(); ++i)

values[i] = v[indices[i]];

Precondition: The sizes of the indices and values arrays must be identical.

◆ extract_subvector_to() [2/2]

template<typename ForwardIterator , typename OutputIterator >

void PETScWrappers::VectorBase::extract_subvector_to	(	const ForwardIterator	indices_begin,
		const ForwardIterator	indices_end,
		OutputIterator	values_begin
	)		const

inherited

Instead of getting individual elements of a vector via operator(), this function allows getting a whole set of elements at once. In contrast to the previous function, this function obtains the indices of the elements by dereferencing all elements of the iterator range provided by the first two arguments, and puts the vector values into memory locations obtained by dereferencing a range of iterators starting at the location pointed to by the third argument.

If the current vector is called v, then this function is the equivalent to the code

ForwardIterator indices_p = indices_begin;
OutputIterator  values_p  = values_begin;
while (indices_p != indices_end)
{
  *values_p = v[*indices_p];
  ++indices_p;
  ++values_p;
}

Precondition: It must be possible to write into as many memory locations starting at values_begin as there are iterators between indices_begin and indices_end.

◆ add() [1/6]

void PETScWrappers::VectorBase::add	(	const std::vector< size_type > &	indices,
		const std::vector< PetscScalar > &	values
	)

inherited

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

Definition at line 488 of file petsc_vector_base.cc.

◆ add() [2/6]

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

inherited

This is a second collective add operation. As a difference, this function takes a deal.II vector of values.

Definition at line 499 of file petsc_vector_base.cc.

◆ add() [3/6]

void PETScWrappers::VectorBase::add	(	const size_type	n_elements,
		const size_type *	indices,
		const PetscScalar *	values
	)

inherited

Take an address where n_elements are stored contiguously and add them into the vector. Handles all cases which are not covered by the other two add() functions above.

Definition at line 510 of file petsc_vector_base.cc.

◆ add() [4/6]

void PETScWrappers::VectorBase::add ( const PetscScalar s )

inherited

Addition of s to all components. Note that s is a scalar and not a vector.

Definition at line 921 of file petsc_vector_base.cc.

◆ add() [5/6]

void PETScWrappers::VectorBase::add	(	const PetscScalar	a,
		const VectorBase &	V
	)

inherited

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

Definition at line 933 of file petsc_vector_base.cc.

◆ add() [6/6]

void PETScWrappers::VectorBase::add	(	const PetscScalar	a,
		const VectorBase &	V,
		const PetscScalar	b,
		const VectorBase &	W
	)

inherited

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

Definition at line 945 of file petsc_vector_base.cc.

◆ operator*()

PetscScalar PETScWrappers::VectorBase::operator* ( const VectorBase & vec ) const

inherited

Return the scalar product of two vectors. The vectors must have the same size.

For complex valued vector, this gives \(\left(v^\ast,vec\right)\).

Definition at line 520 of file petsc_vector_base.cc.

◆ norm_sqr()

VectorBase::real_type PETScWrappers::VectorBase::norm_sqr ( ) const

inherited

Return the square of the \(l_2\)-norm.

Definition at line 612 of file petsc_vector_base.cc.

◆ mean_value()

PetscScalar PETScWrappers::VectorBase::mean_value ( ) const

inherited

Return the mean value of the elements of this vector.

Definition at line 621 of file petsc_vector_base.cc.

◆ l1_norm()

VectorBase::real_type PETScWrappers::VectorBase::l1_norm ( ) const

inherited

\(l_1\)-norm of the vector. The sum of the absolute values.

Note: In complex-valued PETSc priori to 3.7.0 this norm is implemented as the sum of absolute values of real and imaginary parts of elements of a complex vector.

Definition at line 672 of file petsc_vector_base.cc.

◆ l2_norm()

VectorBase::real_type PETScWrappers::VectorBase::l2_norm ( ) const

inherited

\(l_2\)-norm of the vector. The square root of the sum of the squares of the elements.

Definition at line 685 of file petsc_vector_base.cc.

◆ lp_norm()

VectorBase::real_type PETScWrappers::VectorBase::lp_norm ( const real_type p ) const

inherited

\(l_p\)-norm of the vector. The pth root of the sum of the pth powers of the absolute values of the elements.

Definition at line 698 of file petsc_vector_base.cc.

◆ linfty_norm()

VectorBase::real_type PETScWrappers::VectorBase::linfty_norm ( ) const

inherited

\(l_\infty\)-norm of the vector. Return the value of the vector element with the maximum absolute value.

Definition at line 740 of file petsc_vector_base.cc.

◆ add_and_dot()

PetscScalar PETScWrappers::VectorBase::add_and_dot	(	const PetscScalar	a,
		const VectorBase &	V,
		const VectorBase &	W
	)

inherited

Performs 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

this->add(a, V);

return_value = *this * W;

PETScWrappers::VectorBase::add

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

Definition petsc_vector_base.cc:488

The reason this function exists is for compatibility with deal.II's own vector classes which can implement this functionality with less memory transfer. However, for PETSc vectors such a combined operation is not natively supported and thus the cost is completely equivalent as calling the two methods separately.

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

Definition at line 542 of file petsc_vector_base.cc.

◆ min()

VectorBase::real_type PETScWrappers::VectorBase::min ( ) const

inherited

Return the value of the vector element with the largest negative value.

Deprecated:: This function has been deprecated to improve compatibility with other classes inheriting from VectorSpaceVector. If you need to use this functionality then use the PETSc function VecMin instead.

Definition at line 753 of file petsc_vector_base.cc.

◆ max()

VectorBase::real_type PETScWrappers::VectorBase::max ( ) const

inherited

Return the value of the vector element with the largest positive value.

Deprecated:: This function has been deprecated to improve compatibility with other classes inheriting from VectorSpaceVector. If you need to use this functionality then use the PETSc function VecMax instead.

Definition at line 766 of file petsc_vector_base.cc.

◆ is_non_negative()

bool PETScWrappers::VectorBase::is_non_negative ( ) const

inherited

Return true if the vector has no negative entries, i.e. all entries are zero or positive. This function is used, for example, to check whether refinement indicators are really all positive (or zero).

Deprecated:: This function has been deprecated to improve compatibility with other classes inheriting from VectorSpaceVector.

Definition at line 834 of file petsc_vector_base.cc.

◆ operator*=()

VectorBase & PETScWrappers::VectorBase::operator*= ( const PetscScalar factor )

inherited

Multiply the entire vector by a fixed factor.

Definition at line 866 of file petsc_vector_base.cc.

◆ operator/=()

VectorBase & PETScWrappers::VectorBase::operator/= ( const PetscScalar factor )

inherited

Divide the entire vector by a fixed factor.

Definition at line 880 of file petsc_vector_base.cc.

◆ operator+=()

VectorBase & PETScWrappers::VectorBase::operator+= ( const VectorBase & V )

inherited

Add the given vector to the present one.

Definition at line 897 of file petsc_vector_base.cc.

◆ operator-=()

VectorBase & PETScWrappers::VectorBase::operator-= ( const VectorBase & V )

inherited

Subtract the given vector from the present one.

Definition at line 909 of file petsc_vector_base.cc.

◆ sadd() [1/2]

void PETScWrappers::VectorBase::sadd	(	const PetscScalar	s,
		const VectorBase &	V
	)

inherited

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

Definition at line 964 of file petsc_vector_base.cc.

◆ sadd() [2/2]

void PETScWrappers::VectorBase::sadd	(	const PetscScalar	s,
		const PetscScalar	a,
		const VectorBase &	V
	)

inherited

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

Definition at line 976 of file petsc_vector_base.cc.

◆ scale()

void PETScWrappers::VectorBase::scale ( const VectorBase & scaling_factors )

inherited

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.

Definition at line 994 of file petsc_vector_base.cc.

◆ equ()

void PETScWrappers::VectorBase::equ	(	const PetscScalar	a,
		const VectorBase &	V
	)

inherited

Assignment *this = a*V.

Definition at line 1004 of file petsc_vector_base.cc.

◆ write_ascii()

void PETScWrappers::VectorBase::write_ascii ( const PetscViewerFormat format = PETSC_VIEWER_DEFAULT )

inherited

Prints the PETSc vector object values using PETSc internal vector viewer function VecView. The default format prints the vector's contents, including indices of vector elements. For other valid view formats, consult http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/VecView.html

Definition at line 1018 of file petsc_vector_base.cc.

◆ swap()

void PETScWrappers::VectorBase::swap ( VectorBase & v )

inherited

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.

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.

Definition at line 1083 of file petsc_vector_base.cc.

◆ operator const Vec &()

PETScWrappers::VectorBase::operator const Vec & ( ) const

inherited

Conversion operator to gain access to the underlying PETSc type. If you do this, you cut this class off some information it may need, so this conversion operator should only be used if you know what you do. In particular, it should only be used for read-only operations into the vector.

Definition at line 1095 of file petsc_vector_base.cc.

◆ petsc_vector()

Vec & PETScWrappers::VectorBase::petsc_vector ( )

inherited

Return a reference to the underlying PETSc type. It can be used to modify the underlying data, so use it only when you know what you are doing.

Definition at line 1102 of file petsc_vector_base.cc.

◆ memory_consumption()

std::size_t PETScWrappers::VectorBase::memory_consumption ( ) const

inherited

Estimate for the memory consumption (not implemented for this class).

Definition at line 1109 of file petsc_vector_base.cc.

◆ get_mpi_communicator()

MPI_Comm PETScWrappers::VectorBase::get_mpi_communicator ( ) const

inherited

Return the underlying MPI communicator.

◆ do_set_add_operation()

void PETScWrappers::VectorBase::do_set_add_operation	(	const size_type	n_elements,
		const size_type *	indices,
		const PetscScalar *	values,
		const bool	add_values
	)

protectedinherited

Collective set or add operation: This function is invoked by the collective set and add with the add_values flag set to the corresponding value.

Definition at line 1131 of file petsc_vector_base.cc.

◆ determine_ghost_indices()

void PETScWrappers::VectorBase::determine_ghost_indices ( )

protectedinherited

Determine ghost indices from the internal PETSc Vec

Definition at line 243 of file petsc_vector_base.cc.

◆ subscribe()

void Subscriptor::subscribe	(	std::atomic< bool > *const	validity,
		const std::string &	identifier = `""`
	)		const

inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 136 of file subscriptor.cc.

◆ unsubscribe()

void Subscriptor::unsubscribe	(	std::atomic< bool > *const	validity,
		const std::string &	identifier = `""`
	)		const

inherited

Unsubscribes a user from the object.

Note: The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file subscriptor.cc.

◆ n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const

inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

◆ list_subscribers() [1/2]

template<typename StreamType >

void Subscriptor::list_subscribers ( StreamType & stream ) const

inlineinherited

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

◆ list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

◆ serialize()

template<class Archive >

void Subscriptor::serialize	(	Archive &	ar,
		const unsigned int	version
	)

inlineinherited

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

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

◆ check_no_subscribers()

void Subscriptor::check_no_subscribers ( ) const

privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note: Since this function is just a consistency check it does nothing in release mode.; If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 53 of file subscriptor.cc.

Friends And Related Symbol Documentation

◆ swap() [1/2]

void swap	(	Vector &	u,
		Vector &	v
	)

Definition at line 426 of file petsc_vector.h.

◆ swap() [2/2]

void swap	(	VectorBase &	u,
		VectorBase &	v
	)

Definition at line 872 of file petsc_vector_base.h.

Member Data Documentation

◆ vector

Vec PETScWrappers::VectorBase::vector

protectedinherited

A generic vector object in PETSc. The actual type, a sequential vector, is set in the constructor.

Definition at line 816 of file petsc_vector_base.h.

◆ ghosted

bool PETScWrappers::VectorBase::ghosted

protectedinherited

Denotes if this vector has ghost indices associated with it. This means that at least one of the processes in a parallel program has at least one ghost index.

Definition at line 823 of file petsc_vector_base.h.

◆ ghost_indices

IndexSet PETScWrappers::VectorBase::ghost_indices

protectedinherited

This vector contains the global indices of the ghost values. The location in this vector denotes the local numbering, which is used in PETSc.

Definition at line 830 of file petsc_vector_base.h.

◆ last_action

VectorOperation::values PETScWrappers::VectorBase::last_action

mutableprotectedinherited

Store whether the last action was a write or add operation. This variable is mutable so that the accessor classes can write to it, even though the vector object they refer to is constant.

Definition at line 837 of file petsc_vector_base.h.

◆ counter

std::atomic<unsigned int> Subscriptor::counter

mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 219 of file subscriptor.h.

◆ counter_map

std::map<std::string, unsigned int> Subscriptor::counter_map

mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 225 of file subscriptor.h.

◆ validity_pointers

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

mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 241 of file subscriptor.h.

◆ object_info

const std::type_info* Subscriptor::object_info

mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 249 of file subscriptor.h.

◆ mutex

std::mutex Subscriptor::mutex

staticprivateinherited

A mutex used to ensure data consistency when printing out the list of subscribers.

Definition at line 271 of file subscriptor.h.

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

include/deal.II/lac/petsc_vector.h
source/lac/petsc_parallel_vector.cc

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Related Symbols

Detailed Description

Parallel communication model

Accessing individual elements of a vector

Member Typedef Documentation

◆ size_type

◆ value_type

◆ real_type

◆ reference

◆ const_reference

◆ map_value_type

◆ map_iterator

Constructor & Destructor Documentation

◆ Vector() [1/6]

◆ Vector() [2/6]

◆ Vector() [3/6]

◆ Vector() [4/6]

◆ Vector() [5/6]

◆ Vector() [6/6]

Member Function Documentation

◆ clear()

◆ operator=() [1/3]

◆ operator=() [2/3]

◆ operator=() [3/3]

◆ reinit() [1/6]

◆ reinit() [2/6]

◆ reinit() [3/6]

◆ reinit() [4/6]

◆ reinit() [5/6]

◆ print()

◆ all_zero()

◆ create_vector() [1/2]

◆ create_vector() [2/2]

◆ VectorBase() [1/3]

◆ VectorBase() [2/3]

◆ VectorBase() [3/3]

◆ reinit() [6/6]

◆ compress()

◆ operator==()

◆ operator!=()

◆ size()

◆ local_size()

◆ locally_owned_size()

◆ local_range()

◆ in_local_range()

◆ locally_owned_elements()

◆ has_ghost_elements()

◆ ghost_elements()

◆ update_ghost_values()

◆ operator()() [1/2]

◆ operator()() [2/2]

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ set()

◆ extract_subvector_to() [1/2]

◆ extract_subvector_to() [2/2]

◆ add() [1/6]

◆ add() [2/6]

◆ add() [3/6]

◆ add() [4/6]

◆ add() [5/6]

◆ add() [6/6]

◆ operator*()

◆ norm_sqr()

◆ mean_value()

◆ l1_norm()

◆ l2_norm()

◆ lp_norm()

◆ linfty_norm()

◆ add_and_dot()

◆ min()