#include <ghosting_functor.h>

Inheritance diagram for libMesh::GhostingFunctor:

[legend]

Public Types
typedef std::unordered_map< const Elem , const CouplingMatrix >	map_type

Public Member Functions
	GhostingFunctor ()

virtual	~GhostingFunctor ()

virtual void	operator() (const MeshBase::const_element_iterator &range_begin, const MeshBase::const_element_iterator &range_end, processor_id_type p, map_type &coupled_elements)=0

virtual void	mesh_reinit ()

virtual void	dofmap_reinit ()

virtual void	redistribute ()

virtual void	delete_remote_elements ()

Static Public Member Functions
static std::string	get_info ()

static void	print_info (std::ostream &out=libMesh::out)

static unsigned int	n_objects ()

static void	enable_print_counter_info ()

static void	disable_print_counter_info ()

Protected Types
typedef std::map< std::string, std::pair< unsigned int, unsigned int > >	Counts

Protected Member Functions
void	increment_constructor_count (const std::string &name)

void	increment_destructor_count (const std::string &name)

Static Protected Attributes
static Counts	_counts

static Threads::atomic< unsigned int >	_n_objects

static Threads::spin_mutex	_mutex

static bool	_enable_print_counter = true

Detailed Description

This abstract base class defines the interface by which library code and user code can report associations between elements. These associations between elements may be used to keep copies of non-local elements retained on a distributed mesh, may be used to keep element degrees of freedom properly communicated on a distributed vector, and/or may be used to insert coupling entries between elements' degrees of freedom to a sparsity matrix.

We can think of three levels of "element dependencies". An element K1 has a coupling dependency on K2 if the dofs on K1 might (modulo the coupling matrix) need sparsity pattern entries for dofs on K2. An element K1 has an algebraic dependency on K2 if a processor which owns K1 might need to examine the solution dof values on K2. An element K1 has a geometric dependency on K2 if a processor which owns K1 might need to examine the geometry of K2. For any element K, we could call the set of coupling-ghosted ("coupled") elements C(K), call the set of algebraic-ghosted ("evaluable") elements E(K), and call the set of geometry-ghosted ("ghosted") elements G(K).

It should be safe to assume that, for any element K, C(K) implies E(K) implies G(K). These will be one-way implications in some problems and equality relations in others.

We can think of these as operators on sets of elements in the obvious way, e.g.: G({K}) = {G(Ki) for all Ki in {K}}.

The user should omit from their implementations relations which we already have enough information to understand implicitly. For instance, K is obviously in C(K), so a GhostingFunctor should never bother telling us so. We may have a PeriodicBoundary, a hanging node constraint equation, or a user-defined constraint equation which creates a dependency between two elements; if so then we don't need the user to also tell us about that relation (although a PeriodicBoundary use will cause the library to create its own PeriodicGhostingFunctor for internal use).

Users may only care about a subset of variables in distant evaluable elements, so we could imagine defining E_v(K) for each variable number v, in which case E(K) under our previous definition is the union of E_v(K) forall v, and this is what would be included in G(K) when deciding what to ghost, but our send_list would only include the subset of variables we need, so communication and memory use would be much reduced. However, for efficiency and API simplicity, we instead define the isomorphic operator E'(K) which gives a set of ordered pairs of elements and variable-number-sets, from which a consistent E(K) would be derived by ignoring the variable-number-sets.

For C(K), there are similar issues: e.g. we may want some discontinuous variables to couple only within their own element but other discontinuous variables to couple in a DG/FVM way. This could extend to more than one variable index: i.e. a dof for variable v1 in element K1 would depend on a dof for variable v2 in element K2 iff K2 is in C_v1_v2(K1). This would induce a consistent E_v(K) = union of C_w_v(K) forall variable indices w. Again, the equivalent API alternative we use here is for C'(K) to return a set of ordered pairs of elements and variable-number-pair-sets.

We return variable-stuff-sets as pointers to CouplingMatrix. That way, in the common case where the user cares about all variables and couple to all variables, all the functor needs to return for variable-number-sets and variable-number-pair-sets is nullptr (which as in other libMesh APIs will be interpreted and documented to mean the full set). In the common case where the user wants coupling between elements to match coupling within elements, the functor can return the same pointer as DofMap::_coupling_matrix. Even in the less common cases, the user can store common variable-number-sets and variable-number-pair sets as CouplingMatrix members of a functor object of their subclass, and setting up a few of those matrices then setting lots of those pointers is cheap.

The definition of the CouplingMatrix for a variable-dependent E' should be consistent with the requirements that would have been imposed had that matrix been used for a C'. In other words, if the returned CouplingMatrix CM has CM(i,j)==true for any i, then variable j will be evaluable on the algebraically ghosted element.

After a GhostingFunctor has been created, a reference to it can be passed to MeshBase::add_ghosting_functor to expand geometric ghosting, or to DofMap::add_algebraic_ghosting_functor to expand both algebraic and geometric ghosting, or to DofMap::add_coupling_functor to expand coupling along with both types of ghosting.

Note that when an element is specified in algebraic ghosting or coupling queries, only degrees of freedom for the variables supported on that element are thereby ghosted and/or coupled. Any unsupported variable dofs associated with the element's nodes (e.g. subdomain-restricted variables on a neighboring subdomain) will be unaffected.

Author: Roy H. Stogner

Date: 2016

Definition at line 136 of file ghosting_functor.h.

Member Typedef Documentation

◆ Counts

typedef std::map<std::string, std::pair<unsigned int, unsigned int> > libMesh::ReferenceCounter::Counts

protectedinherited

Data structure to log the information. The log is identified by the class name.

Definition at line 117 of file reference_counter.h.

◆ map_type

typedef std::unordered_map<const Elem*, const CouplingMatrix*> libMesh::GhostingFunctor::map_type

What elements do we care about and what variables do we care about on each element?

Definition at line 154 of file ghosting_functor.h.

Constructor & Destructor Documentation

◆ GhostingFunctor()

libMesh::GhostingFunctor::GhostingFunctor ( )

inline

Constructor. Empty in the base class.

Definition at line 143 of file ghosting_functor.h.

143 {}

◆ ~GhostingFunctor()

virtual libMesh::GhostingFunctor::~GhostingFunctor ( )

inlinevirtual

Virtual destructor; this is an abstract base class.

Definition at line 148 of file ghosting_functor.h.

148 {}

Member Function Documentation

◆ delete_remote_elements()

virtual void libMesh::GhostingFunctor::delete_remote_elements ( )

inlinevirtual

GhostingFunctor subclasses with relatively long-lasting caches may want to delete the no-longer-relevant parts of those caches after a redistribution is complete.

Reimplemented in libMesh::PointNeighborCoupling, and libMesh::DefaultCoupling.

Definition at line 204 of file ghosting_functor.h.

204 {};

◆ disable_print_counter_info()

void libMesh::ReferenceCounter::disable_print_counter_info ( )

staticinherited

Definition at line 106 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter.

Referenced by libMesh::LibMeshInit::LibMeshInit().

 {
   _enable_print_counter = false;
   return;
 }

◆ dofmap_reinit()

virtual void libMesh::GhostingFunctor::dofmap_reinit ( )

inlinevirtual

For algebraic ghosting or coupling functors we also call dofmap_reinit() later, after dofs have been distributed on the new mesh but before the functors have been queried for send_list or sparsity pattern calculations.

Definition at line 185 of file ghosting_functor.h.

185 {};

◆ enable_print_counter_info()

void libMesh::ReferenceCounter::enable_print_counter_info ( )

staticinherited

Methods to enable/disable the reference counter output from print_info()

Definition at line 100 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter.

 {
   _enable_print_counter = true;
   return;
 }

◆ get_info()

std::string libMesh::ReferenceCounter::get_info ( )

staticinherited

Gets a string containing the reference information.

Definition at line 47 of file reference_counter.C.

References libMesh::ReferenceCounter::_counts, and libMesh::Quality::name().

Referenced by libMesh::ReferenceCounter::print_info().

 {
 #if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)
 
   std::ostringstream oss;
 
   oss << '\n'
       << " ---------------------------------------------------------------------------- \n"
       << "| Reference count information                                                |\n"
       << " ---------------------------------------------------------------------------- \n";
 
   for (const auto & pr : _counts)
     {
       const std::string name(pr.first);
       const unsigned int creations    = pr.second.first;
       const unsigned int destructions = pr.second.second;
 
       oss << "| " << name << " reference count information:\n"
           << "|  Creations:    " << creations    << '\n'
           << "|  Destructions: " << destructions << '\n';
     }
 
   oss << " ---------------------------------------------------------------------------- \n";
 
   return oss.str();
 
 #else
 
   return "";
 
 #endif
 }

◆ increment_constructor_count()

void libMesh::ReferenceCounter::increment_constructor_count ( const std::string & name )

inlineprotectedinherited

Increments the construction counter. Should be called in the constructor of any derived class that will be reference counted.

Definition at line 181 of file reference_counter.h.

References libMesh::ReferenceCounter::_counts, libMesh::Quality::name(), and libMesh::Threads::spin_mtx.

Referenced by libMesh::ReferenceCountedObject< RBParametrized >::ReferenceCountedObject().

 {
   Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
   std::pair<unsigned int, unsigned int> & p = _counts[name];
 
   p.first++;
 }

◆ increment_destructor_count()

void libMesh::ReferenceCounter::increment_destructor_count ( const std::string & name )

inlineprotectedinherited

Increments the destruction counter. Should be called in the destructor of any derived class that will be reference counted.

Definition at line 194 of file reference_counter.h.

References libMesh::ReferenceCounter::_counts, libMesh::Quality::name(), and libMesh::Threads::spin_mtx.

Referenced by libMesh::ReferenceCountedObject< RBParametrized >::~ReferenceCountedObject().

 {
   Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
   std::pair<unsigned int, unsigned int> & p = _counts[name];
 
   p.second++;
 }

◆ mesh_reinit()

virtual void libMesh::GhostingFunctor::mesh_reinit ( )

inlinevirtual

GhostingFunctor subclasses which cache data will need to initialize that cache. We call mesh_reinit() whenever the relevant Mesh has changed, but before remote elements on a distributed mesh are deleted.

Reimplemented in libMesh::PointNeighborCoupling, and libMesh::DefaultCoupling.

Definition at line 177 of file ghosting_functor.h.

177 {};

◆ n_objects()

static unsigned int libMesh::ReferenceCounter::n_objects ( )

inlinestaticinherited

Prints the number of outstanding (created, but not yet destroyed) objects.

Definition at line 83 of file reference_counter.h.

References libMesh::ReferenceCounter::_n_objects.

84 { return _n_objects; }

libMesh::ReferenceCounter::_n_objects

static Threads::atomic< unsigned int > _n_objects

Definition: reference_counter.h:130

◆ operator()()

virtual void libMesh::GhostingFunctor::operator()	(	const MeshBase::const_element_iterator &	range_begin,
		const MeshBase::const_element_iterator &	range_end,
		processor_id_type	p,
		map_type &	coupled_elements
	)

pure virtual

For the specified range of active elements, what other elements currently living (whether local or ghosted) on this processor need to be coupled/ghosted to accommodate them? Don't bother to return any results which already have processor_id p.

This API is new, and we should replace "ignoring those on processor p" with "ignoring those which match a predicate functor" eventually.

Implemented in libMesh::DefaultCoupling, libMesh::PointNeighborCoupling, libMesh::SiblingCoupling, and libMesh::GhostPointNeighbors.

◆ print_info()

void libMesh::ReferenceCounter::print_info ( std::ostream & out = libMesh::out )

staticinherited

Prints the reference information, by default to libMesh::out.

Definition at line 87 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter, and libMesh::ReferenceCounter::get_info().

 {
   if (_enable_print_counter)
     out_stream << ReferenceCounter::get_info();
 }

◆ redistribute()

virtual void libMesh::GhostingFunctor::redistribute ( )

inlinevirtual

GhostingFunctor subclasses with relatively long-lasting caches may want to redistribute those caches whenever the relevant Mesh is redistributed; we will give them an opportunity when that happens. At the point in the code where this is called, element processor ids have been set to their new destinations, and those elements have been copied to their new destinations, but the elements have not yet been deleted by the processors which previously held them..

Reimplemented in libMesh::PointNeighborCoupling, and libMesh::DefaultCoupling.

Definition at line 197 of file ghosting_functor.h.

197 {};

Member Data Documentation

◆ _counts

ReferenceCounter::Counts libMesh::ReferenceCounter::_counts

staticprotectedinherited

Actually holds the data.

Definition at line 122 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::get_info(), libMesh::ReferenceCounter::increment_constructor_count(), and libMesh::ReferenceCounter::increment_destructor_count().

◆ _enable_print_counter

bool libMesh::ReferenceCounter::_enable_print_counter = true

staticprotectedinherited

Flag to control whether reference count information is printed when print_info is called.

Definition at line 141 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::disable_print_counter_info(), libMesh::ReferenceCounter::enable_print_counter_info(), and libMesh::ReferenceCounter::print_info().

◆ _mutex

Threads::spin_mutex libMesh::ReferenceCounter::_mutex

staticprotectedinherited

Mutual exclusion object to enable thread-safe reference counting.

Definition at line 135 of file reference_counter.h.

◆ _n_objects

Threads::atomic< unsigned int > libMesh::ReferenceCounter::_n_objects

staticprotectedinherited

The number of objects. Print the reference count information when the number returns to 0.

Definition at line 130 of file reference_counter.h.

Referenced by libMesh::ReferenceCounter::n_objects(), libMesh::ReferenceCounter::ReferenceCounter(), and libMesh::ReferenceCounter::~ReferenceCounter().

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

ghosting_functor.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Types

Protected Member Functions

Static Protected Attributes

Detailed Description

Member Typedef Documentation

◆ Counts

◆ map_type

Constructor & Destructor Documentation

◆ GhostingFunctor()

◆ ~GhostingFunctor()

Member Function Documentation

◆ delete_remote_elements()

◆ disable_print_counter_info()

◆ dofmap_reinit()

◆ enable_print_counter_info()

◆ get_info()

◆ increment_constructor_count()

◆ increment_destructor_count()

◆ mesh_reinit()

◆ n_objects()

◆ operator()()

◆ print_info()

◆ redistribute()

Member Data Documentation

◆ _counts

◆ _enable_print_counter

◆ _mutex

◆ _n_objects