Epetra_Map: A class for partitioning vectors and matrices. More...

#include <Epetra_Map.h>

Inheritance diagram for Epetra_Map:

Public Member Functions
	Epetra_Map (int NumGlobalElements, int IndexBase, const Epetra_Comm &Comm)
	Epetra_Map constructor for a Epetra-defined uniform linear distribution of elements. More...

	Epetra_Map (long long NumGlobalElements, int IndexBase, const Epetra_Comm &Comm)

	Epetra_Map (long long NumGlobalElements, long long IndexBase, const Epetra_Comm &Comm)

	Epetra_Map (int NumGlobalElements, int NumMyElements, int IndexBase, const Epetra_Comm &Comm)
	Epetra_Map constructor for a user-defined linear distribution of elements. More...

	Epetra_Map (long long NumGlobalElements, int NumMyElements, int IndexBase, const Epetra_Comm &Comm)

	Epetra_Map (long long NumGlobalElements, int NumMyElements, long long IndexBase, const Epetra_Comm &Comm)

	Epetra_Map (int NumGlobalElements, int NumMyElements, const int *MyGlobalElements, int IndexBase, const Epetra_Comm &Comm)
	Epetra_Map constructor for a user-defined arbitrary distribution of elements. More...

	Epetra_Map (long long NumGlobalElements, int NumMyElements, const long long *MyGlobalElements, int IndexBase, const Epetra_Comm &Comm)

	Epetra_Map (long long NumGlobalElements, int NumMyElements, const long long *MyGlobalElements, long long IndexBase, const Epetra_Comm &Comm)

	Epetra_Map (long long NumGlobal_Elements, int NumMy_Elements, const long long *myGlobalElements, int indexBase, const Epetra_Comm &comm, bool UserIsDistributedGlobal, long long UserMinAllGID, long long UserMaxAllGID)
	Epetra_Map constructor for a user-defined arbitrary distribution of elements, where the user provides all the globals. More...

	Epetra_Map (long long NumGlobal_Elements, int NumMy_Elements, const long long *myGlobalElements, long long indexBase, const Epetra_Comm &comm, bool UserIsDistributedGlobal, long long UserMinAllGID, long long UserMaxAllGID)

	Epetra_Map (int NumGlobal_Elements, int NumMy_Elements, const int *myGlobalElements, int indexBase, const Epetra_Comm &comm, bool UserIsDistributedGlobal, int UserMinAllGID, int UserMaxAllGID)

	Epetra_Map (const Epetra_Map &map)
	Epetra_Map copy constructor. More...

virtual	~Epetra_Map (void)
	Epetra_Map destructor. More...

Epetra_Map &	operator= (const Epetra_Map &map)
	Assignment Operator. More...

Epetra_Map *	RemoveEmptyProcesses () const
	Return a new BlockMap with processes with zero elements removed. More...

Epetra_Map *	ReplaceCommWithSubset (const Epetra_Comm *Comm) const
	Replace this Map's communicator with a subset communicator. More...

Public Member Functions inherited from Epetra_BlockMap
template<>
bool	GlobalIndicesIsType () const

template<>
bool	GlobalIndicesIsType () const

	Epetra_BlockMap (int NumGlobalElements, int ElementSize, int IndexBase, const Epetra_Comm &Comm)
	Epetra_BlockMap constructor for a Epetra-defined uniform linear distribution of constant size elements. More...

	Epetra_BlockMap (long long NumGlobalElements, int ElementSize, int IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (long long NumGlobalElements, int ElementSize, long long IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (int NumGlobalElements, int NumMyElements, int ElementSize, int IndexBase, const Epetra_Comm &Comm)
	Epetra_BlockMap constructor for a user-defined linear distribution of constant size elements. More...

	Epetra_BlockMap (long long NumGlobalElements, int NumMyElements, int ElementSize, int IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (long long NumGlobalElements, int NumMyElements, int ElementSize, long long IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (int NumGlobalElements, int NumMyElements, const int *MyGlobalElements, int ElementSize, int IndexBase, const Epetra_Comm &Comm)
	Epetra_BlockMap constructor for a user-defined arbitrary distribution of constant size elements. More...

	Epetra_BlockMap (long long NumGlobalElements, int NumMyElements, const long long *MyGlobalElements, int ElementSize, int IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (long long NumGlobalElements, int NumMyElements, const long long *MyGlobalElements, int ElementSize, long long IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (int NumGlobalElements, int NumMyElements, const int MyGlobalElements, const int ElementSizeList, int IndexBase, const Epetra_Comm &Comm)
	Epetra_BlockMap constructor for a user-defined arbitrary distribution of variable size elements. More...

	Epetra_BlockMap (long long NumGlobalElements, int NumMyElements, const long long MyGlobalElements, const int ElementSizeList, int IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (long long NumGlobalElements, int NumMyElements, const long long MyGlobalElements, const int ElementSizeList, long long IndexBase, const Epetra_Comm &Comm)

	Epetra_BlockMap (long long NumGlobal_Elements, int NumMy_Elements, const long long *myGlobalElements, int ElementSize, int indexBase, const Epetra_Comm &comm, bool UserIsDistributedGlobal, long long UserMinAllGID, long long UserMaxAllGID)
	Epetra_BlockMap constructor for a user-defined arbitrary distribution of constant size elements, where the user provides all the globals. More...

	Epetra_BlockMap (long long NumGlobal_Elements, int NumMy_Elements, const long long *myGlobalElements, int ElementSize, long long indexBase, const Epetra_Comm &comm, bool UserIsDistributedGlobal, long long UserMinAllGID, long long UserMaxAllGID)

	Epetra_BlockMap (int NumGlobal_Elements, int NumMy_Elements, const int *myGlobalElements, int ElementSize, int indexBase, const Epetra_Comm &comm, bool UserIsDistributedGlobal, int UserMinAllGID, int UserMaxAllGID)

	Epetra_BlockMap (const Epetra_BlockMap &map)
	Epetra_BlockMap copy constructor. More...

virtual	~Epetra_BlockMap (void)
	Epetra_BlockMap destructor. More...

int	RemoteIDList (int NumIDs, const int GIDList, int PIDList, int *LIDList) const
	Returns the processor IDs and corresponding local index value for a given list of global indices. More...

int	RemoteIDList (int NumIDs, const long long GIDList, int PIDList, int *LIDList) const

int	RemoteIDList (int NumIDs, const int GIDList, int PIDList, int LIDList, int SizeList) const
	Returns the processor IDs, corresponding local index value, and element size for a given list of global indices. More...

int	RemoteIDList (int NumIDs, const long long GIDList, int PIDList, int LIDList, int SizeList) const

int	LID (int GID) const
	Returns local ID of global ID, return -1 if not found on this processor. More...

int	LID (long long GID) const

int	GID (int LID) const
	Returns global ID of local ID, return IndexBase-1 if not found on this processor. More...

long long	GID64 (int LID) const

int	FindLocalElementID (int PointID, int &ElementID, int &ElementOffset) const
	Returns the LID of the element that contains the given local PointID, and the Offset of the point in that element. More...

bool	MyGID (int GID_in) const
	Returns true if the GID passed in belongs to the calling processor in this map, otherwise returns false. More...

bool	MyGID (long long GID_in) const

bool	MyLID (int lid) const
	Returns true if the LID passed in belongs to the calling processor in this map, otherwise returns false. More...

int	MinAllGID () const
	Returns the minimum global ID across the entire map. More...

long long	MinAllGID64 () const

int	MaxAllGID () const
	Returns the maximum global ID across the entire map. More...

long long	MaxAllGID64 () const

int	MinMyGID () const
	Returns the minimum global ID owned by this processor. More...

long long	MinMyGID64 () const

int	MaxMyGID () const
	Returns the maximum global ID owned by this processor. More...

long long	MaxMyGID64 () const

int	MinLID () const
	The minimum local index value on the calling processor. More...

int	MaxLID () const
	The maximum local index value on the calling processor. More...

int	NumGlobalElements () const
	Number of elements across all processors. More...

long long	NumGlobalElements64 () const

int	NumMyElements () const
	Number of elements on the calling processor. More...

int	MyGlobalElements (int *MyGlobalElementList) const
	Puts list of global elements on this processor into the user-provided array. More...

int	MyGlobalElements (long long *MyGlobalElementList) const

int	MyGlobalElementsPtr (int *&MyGlobalElementList) const

int	MyGlobalElementsPtr (long long *&MyGlobalElementList) const

int	ElementSize () const
	Returns the size of elements in the map; only valid if map has constant element size. More...

int	ElementSize (int LID) const
	Size of element for specified LID. More...

int	FirstPointInElement (int LID) const
	Returns the requested entry in the FirstPointInElementList; see FirstPointInElementList() for details. More...

int	IndexBase () const
	Index base for this map. More...

long long	IndexBase64 () const

int	NumGlobalPoints () const
	Number of global points for this map; equals the sum of all element sizes across all processors. More...

long long	NumGlobalPoints64 () const

int	NumMyPoints () const
	Number of local points for this map; equals the sum of all element sizes on the calling processor. More...

int	MinMyElementSize () const
	Minimum element size on the calling processor. More...

int	MaxMyElementSize () const
	Maximum element size on the calling processor. More...

int	MinElementSize () const
	Minimum element size across all processors. More...

int	MaxElementSize () const
	Maximum element size across all processors. More...

bool	UniqueGIDs () const
	Returns true if map GIDs are 1-to-1. More...

bool	GlobalIndicesInt () const
	Returns true if map create with int NumGlobalElements. More...

bool	GlobalIndicesLongLong () const
	Returns true if map create with long long NumGlobalElements. More...

template<typename int_type >
bool	GlobalIndicesIsType () const

bool	GlobalIndicesTypeValid () const

bool	GlobalIndicesTypeMatch (const Epetra_BlockMap &other) const

bool	ConstantElementSize () const
	Returns true if map has constant element size. More...

bool	SameBlockMapDataAs (const Epetra_BlockMap &Map) const
	Returns true if maps share same block map data underneath. More...

bool	SameAs (const Epetra_BlockMap &Map) const
	Returns true if this and Map are identical maps. More...

bool	PointSameAs (const Epetra_BlockMap &Map) const
	Returns true if this and Map have identical point-wise structure. More...

bool	LinearMap () const
	Returns true if the global ID space is contiguously divided (but not necessarily uniformly) across all processors. More...

bool	DistributedGlobal () const
	Returns true if map is defined across more than one processor. More...

int *	MyGlobalElements () const
	Pointer to internal array containing list of global IDs assigned to the calling processor. More...

long long *	MyGlobalElements64 () const

void	MyGlobalElements (const int &IntGIDs, const long long &LLGIDs) const

void	MyGlobalElements (int &IntGIDs, long long &LLGIDs)

int *	FirstPointInElementList () const
	Pointer to internal array containing a mapping between the local elements and the first local point number in each element. More...

int *	ElementSizeList () const
	List of the element sizes corresponding to the array MyGlobalElements(). More...

int *	PointToElementList () const
	For each local point, indicates the local element ID that the point belongs to. More...

int	ElementSizeList (int *ElementSizeList) const
	Same as ElementSizeList() except it fills the user array that is passed in. More...

int	FirstPointInElementList (int *FirstPointInElementList) const
	Same as FirstPointInElementList() except it fills the user array that is passed in. More...

int	PointToElementList (int *PointToElementList) const
	Same as PointToElementList() except it fills the user array that is passed in. More...

virtual void	Print (std::ostream &os) const
	Print object to an output stream. More...

const Epetra_Comm &	Comm () const
	Access function for Epetra_Comm communicator. More...

bool	IsOneToOne () const

Epetra_BlockMap &	operator= (const Epetra_BlockMap &map)
	Assignment Operator. More...

int	ReferenceCount () const
	Returns the reference count of BlockMapData. More...

const Epetra_BlockMapData *	DataPtr () const
	Returns a pointer to the BlockMapData instance this BlockMap uses. More...

Epetra_BlockMap *	RemoveEmptyProcesses () const
	Return a new BlockMap with processes with zero elements removed. More...

Epetra_BlockMap *	ReplaceCommWithSubset (const Epetra_Comm *Comm) const
	Replace this BlockMap's communicator with a subset communicator. More...

Public Member Functions inherited from Epetra_Object
	Epetra_Object (int TracebackModeIn=-1, bool set_label=true)
	Epetra_Object Constructor. More...

	Epetra_Object (const char *const Label, int TracebackModeIn=-1)
	Epetra_Object Constructor. More...

	Epetra_Object (const Epetra_Object &Object)
	Epetra_Object Copy Constructor. More...

virtual	~Epetra_Object ()
	Epetra_Object Destructor. More...

virtual void	SetLabel (const char *const Label)
	Epetra_Object Label definition using char *. More...

virtual const char *	Label () const
	Epetra_Object Label access funtion. More...

virtual int	ReportError (const std::string Message, int ErrorCode) const
	Error reporting method. More...

Additional Inherited Members
Static Public Member Functions inherited from Epetra_Object
static void	SetTracebackMode (int TracebackModeValue)
	Set the value of the Epetra_Object error traceback report mode. More...

static int	GetTracebackMode ()
	Get the value of the Epetra_Object error report mode. More...

static std::ostream &	GetTracebackStream ()
	Get the output stream for error reporting. More...

Static Public Attributes inherited from Epetra_Object
static int	TracebackMode

Protected Member Functions inherited from Epetra_BlockMap
void	CleanupData ()

Protected Member Functions inherited from Epetra_Object
std::string	toString (const int &x) const

std::string	toString (const long long &x) const

std::string	toString (const double &x) const

Protected Attributes inherited from Epetra_BlockMap
Epetra_BlockMapData *	BlockMapData_

Detailed Description

Epetra_Map: A class for partitioning vectors and matrices.

It is often the case that multiple matrix and vector objects have an identical distribution of elements on a parallel machine. The Epetra_Map class keep information that describes this distribution for matrices and vectors.

Epetra_Map allows the storage and retrieval of the following information. Depending on the constructor that is used, some of the information is defined by the user and some is determined by the constructor. Once a Epetra_Map is constructed any of the following attributes can be obtained by calling a query function that has the name as the attribute, e.g. to get the value of NumGlobalElements, you can call a function NumGlobalElements(). For attributes that are lists, the query functions return the list values in a user allocated array.

NumGlobalElements - The total number of elements across all processors. If this parameter and NumMyElements are both passed into the constructor, one of the three cases will apply:
1. If NumGlobalElements = NumMyElements (and not equal to zero) the map is defined to be a local replicated map. In this case, objects constructed using this map will be identically replicated across all processors in the communicator.
2. If NumGlobalElements = -1 and NumMyElements is passed in then NumGlobalElements will be computed as the sum of NumMyElements across all processors.
3. If neither of the above is true, NumGlobalElements will be checked against the sum of NumMyElements across all processors. An error is issued if the comparison is not equal.
NumMyElements - The number of elements owned by the calling processor.
MyGlobalElements - A list of length NumMyElements that contains the global element IDs of the elements owned by the calling processor.
IndexBase - The base integer value for indexed array references. Typically this is 0 for C/C++ and 1 for Fortran, but it can be set to any integer value.
Comm - The Epetra_Comm communicator. This communicator can in turn be queried for processor rank and size information.

In addition to the information above that is passed in to or created by the Epetra_Map constructor, the following attributes are computed and available via query to the user using the same scheme as above, e.g., use NumGlobalPoints() to get the value of NumGlobalPoints.

NumGlobalPoints - The total number of points across all processors.
NumMyPoints - The number of points on the calling processor.
MinAllGID - The minimum global index value across all processors.
MaxAllGID - The maximum global index value across all processors.
MinMyGID - The minimum global index value on the calling processor.
MaxMyGID - The maximum global index value on the calling processor.
MinLID - The minimum local index value on the calling processor.
MaxLID - The maximum local index value on the calling processor.

The following functions allow boolean tests for certain properties.

LinearMap() - Returns true if the elements are distributed linear across processors, i.e., processor 0 gets the first n/p elements, processor 1 gets the next n/p elements, etc. where n is the number of elements and p is the number of processors.
DistributedGlobal() - Returns true if the element space of the map spans more than one processor. This will be true in most cases, but will be false in serial cases and for objects that are created via the derived Epetra_LocalMap class.

Warning: An Epetra_Comm object is required for all Epetra_Map constructors.

Note: In the current implementation, Epetra_BlockMap is the base class for Epetra_Map.

Definition at line 127 of file Epetra_Map.h.

Constructor & Destructor Documentation

Epetra_Map::Epetra_Map	(	int	NumGlobalElements,
		int	IndexBase,
		const Epetra_Comm &	Comm
	)

Epetra_Map constructor for a Epetra-defined uniform linear distribution of elements.

Creates a map that distributes NumGlobalElements elements evenly across all processors in the Epetra_Comm communicator. If NumGlobalElements does not divide exactly into the number of processors, the first processors in the communicator get one extra element until the remainder is gone.

Parameters

In	NumGlobalElements - Number of elements to distribute.
In	IndexBase - Minimum index value used for arrays that use this map. Typically 0 for C/C++ and 1 for Fortran.
In	Comm - Epetra_Comm communicator containing information on the number of processors.

Returns: Pointer to a Epetra_Map object.

Definition at line 54 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobalElements,
		int	IndexBase,
		const Epetra_Comm &	Comm
	)

Definition at line 61 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobalElements,
		long long	IndexBase,
		const Epetra_Comm &	Comm
	)

Definition at line 67 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	int	NumGlobalElements,
		int	NumMyElements,
		int	IndexBase,
		const Epetra_Comm &	Comm
	)

Epetra_Map constructor for a user-defined linear distribution of elements.

Creates a map that puts NumMyElements on the calling processor. If NumGlobalElements=-1, the number of global elements will be the computed sum of NumMyElements across all processors in the Epetra_Comm communicator.

Parameters

In	NumGlobalElements - Number of elements to distribute. Must be either -1 or equal to the computed sum of NumMyElements across all processors in the Epetra_Comm communicator.
In	NumMyElements - Number of elements owned by the calling processor.
In	IndexBase - Minimum index value used for arrays that use this map. Typically 0 for C/C++ and 1 for Fortran.
In	Comm - Epetra_Comm communicator containing information on the number of processors.

Returns: Pointer to a Epetra_Map object.

Definition at line 76 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobalElements,
		int	NumMyElements,
		int	IndexBase,
		const Epetra_Comm &	Comm
	)

Definition at line 83 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobalElements,
		int	NumMyElements,
		long long	IndexBase,
		const Epetra_Comm &	Comm
	)

Definition at line 89 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	int	NumGlobalElements,
		int	NumMyElements,
		const int *	MyGlobalElements,
		int	IndexBase,
		const Epetra_Comm &	Comm
	)

Epetra_Map constructor for a user-defined arbitrary distribution of elements.

Creates a map that puts NumMyElements on the calling processor. The indices of the elements are determined from the list MyGlobalElements. If NumGlobalElements=-1, the number of global elements will be the computed sum of NumMyElements across all processors in the Epetra_Comm communicator.

Parameters

In	NumGlobalElements - Number of elements to distribute. Must be either -1 or equal to the computed sum of NumMyElements across all processors in the Epetra_Comm communicator.
In	NumMyElements - Number of elements owned by the calling processor.
In	MyGlobalElements - Integer array of length NumMyElements. The ith entry contains the global index value of the ith element on this processor. Index values are not required to be contiguous on a processor, or to be within the range of 0 to NumGlobalElements. As long as the index values are consistently defined and used, any set of NumGlobalElements distinct integer values is acceptable.
In	IndexBase - Minimum index value used for arrays that use this map. Typically 0 for C/C++ and 1 for Fortran.
In	Comm - Epetra_Comm communicator containing information on the number of processors.

Returns: Pointer to a Epetra_Map object.

Definition at line 98 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobalElements,
		int	NumMyElements,
		const long long *	MyGlobalElements,
		int	IndexBase,
		const Epetra_Comm &	Comm
	)

Definition at line 107 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobalElements,
		int	NumMyElements,
		const long long *	MyGlobalElements,
		long long	IndexBase,
		const Epetra_Comm &	Comm
	)

Definition at line 115 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobal_Elements,
		int	NumMy_Elements,
		const long long *	myGlobalElements,
		int	indexBase,
		const Epetra_Comm &	comm,
		bool	UserIsDistributedGlobal,
		long long	UserMinAllGID,
		long long	UserMaxAllGID
	)

Epetra_Map constructor for a user-defined arbitrary distribution of elements, where the user provides all the globals.

Warning: This method is intended for expert developer use only, and should never be called by user code.

Definition at line 138 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	long long	NumGlobal_Elements,
		int	NumMy_Elements,
		const long long *	myGlobalElements,
		long long	indexBase,
		const Epetra_Comm &	comm,
		bool	UserIsDistributedGlobal,
		long long	UserMinAllGID,
		long long	UserMaxAllGID
	)

Definition at line 147 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map	(	int	NumGlobal_Elements,
		int	NumMy_Elements,
		const int *	myGlobalElements,
		int	indexBase,
		const Epetra_Comm &	comm,
		bool	UserIsDistributedGlobal,
		int	UserMinAllGID,
		int	UserMaxAllGID
	)

Definition at line 127 of file Epetra_Map.cpp.

Epetra_Map::Epetra_Map ( const Epetra_Map & map )

Epetra_Map copy constructor.

Definition at line 159 of file Epetra_Map.cpp.

Epetra_Map::~Epetra_Map ( void )

virtual

Epetra_Map destructor.

Definition at line 165 of file Epetra_Map.cpp.

Member Function Documentation

Epetra_Map & Epetra_Map::operator= ( const Epetra_Map & map )

Assignment Operator.

Definition at line 170 of file Epetra_Map.cpp.

Epetra_Map * Epetra_Map::RemoveEmptyProcesses ( ) const

Return a new BlockMap with processes with zero elements removed.

Warning: This method is only for expert users. Understanding how to use this method correctly requires some familiarity with semantics of MPI communicators.; We make no promises of backwards compatibility for this method. It may go away or change at any time.

This method first computes a new communicator, which contains only those processes in this Map's communicator (the "original communicator") that have a nonzero number of elements in this BlockMap (the "original BlockMap"). It then returns a new BlockMap distributed over the new communicator. The new BlockMap represents the same distribution as the original BlockMap, except that processes containing zero elements are not included in the new BlockMap or its communicator. On processes not included in the new BlockMap or communicator, this method returns NULL.

The returned BlockMap always has a distinct communicator from this BlockMap's original communicator. The new communicator contains a subset of processes from the original communicator. Even if the number of processes in the new communicator equals the number of processes in the original communicator, the new communicator is distinct. (In an MPI implementation, the new communicator is created using MPI_Comm_split.)

This method must be called collectively on the original communicator. It leaves the original Map and communicator unchanged.

This method was intended for applications such as algebraic multigrid or other multilevel preconditioners. Construction of each level of the multilevel preconditioner typically requires constructing sparse matrices, which in turn requires all-reduces over all participating processes at that level. Matrix sizes at successively coarser levels shrink geometrically. At the coarsest levels, some processes might be left with zero rows of the matrix, or the multigrid implementation might "rebalance" (redistribute the matrix) and intentionally leave some processes with zero rows. Removing processes with zero rows makes the all-reduces and other communication operations cheaper.

Definition at line 179 of file Epetra_Map.cpp.

Epetra_Map * Epetra_Map::ReplaceCommWithSubset ( const Epetra_Comm * Comm ) const

Replace this Map's communicator with a subset communicator.

Warning: This method is only for expert users. Understanding how to use this method correctly requires some familiarity with semantics of MPI communicators.; We make no promises of backwards compatibility for this method. It may go away or change at any time.

Precondition: The input communicator's processes are a subset of this Map's current communicator's processes.; On processes which are not included in the input communicator, the input communicator is null.

This method must be called collectively on the original communicator. It leaves the original BlockMap and communicator unchanged.

Note: This method differs from removeEmptyProcesses(), in that it does not assume that excluded processes have zero entries. For example, one might wish to remove empty processes from the row Map of a CrsGraph using removeEmptyProcesses(), and then apply the resulting subset communicator to the column, domain, and range Maps of the same graph. For the latter three Maps, one would in general use this method instead of removeEmptyProcesses(), giving the new row Map's communicator to this method.

Definition at line 279 of file Epetra_Map.cpp.

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

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation