libMesh
Public Types | Public Member Functions | Static Public Member Functions | Protected Types | Protected Member Functions | Static Protected Attributes | List of all members
libMesh::GhostingFunctor Class Referenceabstract

This abstract base class defines the interface by which library code and user code can report associations between elements. More...

#include <ghosting_functor.h>

Inheritance diagram for libMesh::GhostingFunctor:
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Public Types

typedef std::unordered_map< const Elem *, const CouplingMatrix * > map_type
 What elements do we care about and what variables do we care about on each element? More...
 

Public Member Functions

 GhostingFunctor ()
 Constructor. More...
 
virtual ~GhostingFunctor ()
 Virtual destructor; this is an abstract base class. More...
 
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
 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. More...
 
virtual void mesh_reinit ()
 GhostingFunctor subclasses which cache data will need to initialize that cache. More...
 
virtual void dofmap_reinit ()
 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. More...
 
virtual void redistribute ()
 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. More...
 
virtual void delete_remote_elements ()
 GhostingFunctor subclasses with relatively long-lasting caches may want to delete the no-longer-relevant parts of those caches after a redistribution is complete. More...
 

Static Public Member Functions

static std::string get_info ()
 Gets a string containing the reference information. More...
 
static void print_info (std::ostream &out=libMesh::out)
 Prints the reference information, by default to libMesh::out. More...
 
static unsigned int n_objects ()
 Prints the number of outstanding (created, but not yet destroyed) objects. More...
 
static void enable_print_counter_info ()
 Methods to enable/disable the reference counter output from print_info() More...
 
static void disable_print_counter_info ()
 

Protected Types

typedef std::map< std::string, std::pair< unsigned int, unsigned int > > Counts
 Data structure to log the information. More...
 

Protected Member Functions

void increment_constructor_count (const std::string &name)
 Increments the construction counter. More...
 
void increment_destructor_count (const std::string &name)
 Increments the destruction counter. More...
 

Static Protected Attributes

static Counts _counts
 Actually holds the data. More...
 
static Threads::atomic< unsigned int_n_objects
 The number of objects. More...
 
static Threads::spin_mutex _mutex
 Mutual exclusion object to enable thread-safe reference counting. More...
 
static bool _enable_print_counter = true
 Flag to control whether reference count information is printed when print_info is called. More...
 

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 a NULL (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.

Author
Roy H. Stogner
Date
2016

Definition at line 122 of file ghosting_functor.h.

Member Typedef Documentation

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 119 of file reference_counter.h.

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 140 of file ghosting_functor.h.

Constructor & Destructor Documentation

libMesh::GhostingFunctor::GhostingFunctor ( )

Constructor.

Empty in the base class.

Definition at line 129 of file ghosting_functor.h.

129 {}
virtual libMesh::GhostingFunctor::~GhostingFunctor ( )
virtual

Virtual destructor; this is an abstract base class.

Definition at line 134 of file ghosting_functor.h.

134 {}

Member Function Documentation

virtual void libMesh::GhostingFunctor::delete_remote_elements ( )
virtual

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 190 of file ghosting_functor.h.

Referenced by libMesh::MeshCommunication::delete_remote_elements().

190 {};
void libMesh::ReferenceCounter::disable_print_counter_info ( )
staticinherited

Definition at line 107 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter.

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

108 {
109  _enable_print_counter = false;
110  return;
111 }
static bool _enable_print_counter
Flag to control whether reference count information is printed when print_info is called...
virtual void libMesh::GhostingFunctor::dofmap_reinit ( )
virtual

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 171 of file ghosting_functor.h.

Referenced by libMesh::DofMap::distribute_dofs().

171 {};
void libMesh::ReferenceCounter::enable_print_counter_info ( )
staticinherited

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

Definition at line 101 of file reference_counter.C.

References libMesh::ReferenceCounter::_enable_print_counter.

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

102 {
103  _enable_print_counter = true;
104  return;
105 }
static bool _enable_print_counter
Flag to control whether reference count information is printed when print_info is called...
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().

48 {
49 #if defined(LIBMESH_ENABLE_REFERENCE_COUNTING) && defined(DEBUG)
50 
51  std::ostringstream oss;
52 
53  oss << '\n'
54  << " ---------------------------------------------------------------------------- \n"
55  << "| Reference count information |\n"
56  << " ---------------------------------------------------------------------------- \n";
57 
58  for (Counts::iterator it = _counts.begin();
59  it != _counts.end(); ++it)
60  {
61  const std::string name(it->first);
62  const unsigned int creations = it->second.first;
63  const unsigned int destructions = it->second.second;
64 
65  oss << "| " << name << " reference count information:\n"
66  << "| Creations: " << creations << '\n'
67  << "| Destructions: " << destructions << '\n';
68  }
69 
70  oss << " ---------------------------------------------------------------------------- \n";
71 
72  return oss.str();
73 
74 #else
75 
76  return "";
77 
78 #endif
79 }
std::string name(const ElemQuality q)
This function returns a string containing some name for q.
Definition: elem_quality.C:39
static Counts _counts
Actually holds the data.
void libMesh::ReferenceCounter::increment_constructor_count ( const std::string &  name)
protectedinherited

Increments the construction counter.

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

Definition at line 185 of file reference_counter.h.

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

Referenced by libMesh::ReferenceCounter::n_objects(), and libMesh::ReferenceCountedObject< RBParametrized >::ReferenceCountedObject().

186 {
187  Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
188  std::pair<unsigned int, unsigned int> & p = _counts[name];
189 
190  p.first++;
191 }
std::string name(const ElemQuality q)
This function returns a string containing some name for q.
Definition: elem_quality.C:39
spin_mutex spin_mtx
A convenient spin mutex object which can be used for obtaining locks.
Definition: threads.C:29
static Counts _counts
Actually holds the data.
void libMesh::ReferenceCounter::increment_destructor_count ( const std::string &  name)
protectedinherited

Increments the destruction counter.

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

Definition at line 198 of file reference_counter.h.

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

Referenced by libMesh::ReferenceCounter::n_objects(), and libMesh::ReferenceCountedObject< RBParametrized >::~ReferenceCountedObject().

199 {
200  Threads::spin_mutex::scoped_lock lock(Threads::spin_mtx);
201  std::pair<unsigned int, unsigned int> & p = _counts[name];
202 
203  p.second++;
204 }
std::string name(const ElemQuality q)
This function returns a string containing some name for q.
Definition: elem_quality.C:39
spin_mutex spin_mtx
A convenient spin mutex object which can be used for obtaining locks.
Definition: threads.C:29
static Counts _counts
Actually holds the data.
virtual void libMesh::GhostingFunctor::mesh_reinit ( )
virtual

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, libMesh::DefaultCoupling, and AugmentSparsityOnInterface.

Definition at line 163 of file ghosting_functor.h.

Referenced by libMesh::UnstructuredMesh::contract(), and libMesh::MeshBase::prepare_for_use().

163 {};
static unsigned int libMesh::ReferenceCounter::n_objects ( )
staticinherited
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.

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

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

Definition at line 88 of file reference_counter.C.

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

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

89 {
91  out_stream << ReferenceCounter::get_info();
92 }
static std::string get_info()
Gets a string containing the reference information.
static bool _enable_print_counter
Flag to control whether reference count information is printed when print_info is called...
virtual void libMesh::GhostingFunctor::redistribute ( )
virtual

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, libMesh::DefaultCoupling, and AugmentSparsityOnInterface.

Definition at line 183 of file ghosting_functor.h.

Referenced by libMesh::MeshCommunication::redistribute().

183 {};

Member Data Documentation

ReferenceCounter::Counts libMesh::ReferenceCounter::_counts
staticprotectedinherited
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 143 of file reference_counter.h.

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

Threads::spin_mutex libMesh::ReferenceCounter::_mutex
staticprotectedinherited

Mutual exclusion object to enable thread-safe reference counting.

Definition at line 137 of file reference_counter.h.

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 132 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: