Abstract interface for distributed-memory communication. More...

#include <Teuchos_Comm.hpp>

Inheritance diagram for Teuchos::Comm< OrdinalType >:

Public Member Functions
virtual int	getTag () const =0
	The current tag. More...

Destructor
virtual	~Comm ()
	Destructor, declared virtual for safety of derived classes. More...

Query functions
virtual int	getRank () const =0
	Returns the rank of this process. More...

virtual int	getSize () const =0
	Returns the number of processes that make up this communicator. More...

Collective Operations
virtual void	barrier () const =0
	Pause every process in `*this` communicator until all the processes reach this point. More...

virtual void	broadcast (const int rootRank, const Ordinal bytes, char buffer[]) const =0
	Broadcast values from the root process to the slave processes. More...

virtual void	gather (const Ordinal sendBytes, const char sendBuffer[], const Ordinal recvBytes, char recvBuffer[], const int root) const =0
	Gather values from all processes to the root process. More...

virtual void	gatherAll (const Ordinal sendBytes, const char sendBuffer[], const Ordinal recvBytes, char recvBuffer[]) const =0
	Gather values from each process to collect on all processes. More...

virtual void	reduceAll (const ValueTypeReductionOp< Ordinal, char > &reductOp, const Ordinal bytes, const char sendBuffer[], char globalReducts[]) const =0
	Global reduction. More...

virtual void	scan (const ValueTypeReductionOp< Ordinal, char > &reductOp, const Ordinal bytes, const char sendBuffer[], char scanReducts[]) const =0
	Scan reduction. More...

Blocking Point-to-Point Operations
virtual void	send (const Ordinal bytes, const char sendBuffer[], const int destRank) const =0
	Possibly blocking send of data from this process to another process. More...

virtual void	send (const Ordinal bytes, const char sendBuffer[], const int destRank, const int tag) const =0
	Variant of send() that takes a tag. More...

virtual void	ssend (const Ordinal bytes, const char sendBuffer[], const int destRank) const =0
	Always blocking send of data from this process to another process. More...

virtual void	ssend (const Ordinal bytes, const char sendBuffer[], const int destRank, const int tag) const =0
	Variant of ssend() that takes a message tag. More...

virtual int	receive (const int sourceRank, const Ordinal bytes, char recvBuffer[]) const =0
	Blocking receive of data from this process to another process. More...

virtual void	readySend (const ArrayView< const char > &sendBuffer, const int destRank) const =0
	Ready send of data from this process to another process. More...

virtual void	readySend (const Ordinal bytes, const char sendBuffer[], const int destRank, const int tag) const =0
	Variant of readySend() that accepts a message tag. More...

Non-blocking Point-to-Point Operations
virtual RCP< CommRequest < Ordinal > >	isend (const ArrayView< const char > &sendBuffer, const int destRank) const =0
	Non-blocking send. More...

virtual RCP< CommRequest < Ordinal > >	isend (const ArrayView< const char > &sendBuffer, const int destRank, const int tag) const =0
	Variant of isend() that takes a tag. More...

virtual RCP< CommRequest < Ordinal > >	ireceive (const ArrayView< char > &recvBuffer, const int sourceRank) const =0
	Non-blocking receive. More...

virtual RCP< CommRequest < Ordinal > >	ireceive (const ArrayView< char > &recvBuffer, const int sourceRank, const int tag) const =0
	Variant of ireceive that takes a tag. More...

virtual void	waitAll (const ArrayView< RCP< CommRequest< Ordinal > > > &requests) const =0
	Wait on a set of communication requests. More...

virtual void	waitAll (const ArrayView< RCP< CommRequest< Ordinal > > > &requests, const ArrayView< RCP< CommStatus< Ordinal > > > &statuses) const =0
	Wait on communication requests, and return their statuses. More...

virtual RCP< CommStatus < Ordinal > >	wait (const Ptr< RCP< CommRequest< Ordinal > > > &request) const =0
	Wait on a single communication request, and return its status. More...

Subcommunicator Operations
virtual RCP< Comm >	duplicate () const =0
	Duplicate this communicator. More...

virtual RCP< Comm >	split (const int color, const int key) const =0
	Split a communicator into subcommunicators based on color and key. More...

virtual RCP< Comm >	createSubcommunicator (const ArrayView< const int > &ranks) const =0
	Create a subcommunicator containing the specified processes. More...

Public Member Functions inherited from Teuchos::Describable
virtual std::string	description () const
	Return a simple one-line description of this object. More...

virtual void	describe (FancyOStream &out, const EVerbosityLevel verbLevel=verbLevel_default) const
	Print the object with some verbosity level to a FancyOStream. More...

void	describe (std::ostream &out, const EVerbosityLevel verbLevel=verbLevel_default) const
	Version of describe() that takes an std::ostream instead of a FancyOStream. More...

virtual	~Describable ()
	Destructor (marked virtual for memory safety of derived classes). More...

Public Member Functions inherited from Teuchos::LabeledObject
	LabeledObject ()
	Construct with an empty label. More...

virtual	~LabeledObject ()

virtual void	setObjectLabel (const std::string &objectLabel)
	Set the object label (see LabeledObject). More...

virtual std::string	getObjectLabel () const
	Get the object label (see LabeledObject). More...

Related Functions
(Note that these are not member functions.)
enum	EReductionType { REDUCE_SUM, REDUCE_MIN, REDUCE_MAX, REDUCE_AND, REDUCE_BOR }
	Predefined reduction operations that Teuchos::Comm understands. More...

template<typename Ordinal >
int	rank (const Comm< Ordinal > &comm)
	Get the process rank. More...

template<typename Ordinal >
int	size (const Comm< Ordinal > &comm)
	Get the number of processes in the communicator. More...

template<typename Ordinal >
void	barrier (const Comm< Ordinal > &comm)
	Barrier. More...

template<typename Ordinal , typename Packet >
void	broadcast (const Comm< Ordinal > &comm, const int rootRank, const Ordinal count, Packet buffer[])
	Broadcast array of objects that use value semantics. More...

template<typename Ordinal , typename Packet >
void	broadcast (const Comm< Ordinal > &comm, const int rootRank, const ArrayView< Packet > &buffer)
	Broadcast array of objects that use value semantics. More...

template<typename Ordinal , typename Packet >
void	broadcast (const Comm< Ordinal > &comm, const int rootRank, Packet *object)
	Broadcast single object that use value semantics. More...

template<typename Ordinal , typename Packet >
void	broadcast (const Comm< Ordinal > &comm, const int rootRank, const Ptr< Packet > &object)
	Broadcast single object that use value semantics. More...

template<typename Ordinal , typename Packet >
void	broadcast (const Comm< Ordinal > &comm, const Serializer< Ordinal, Packet > &serializer, const int rootRank, const Ordinal count, Packet *const buffer[])
	Broadcast array of objects that use reference semantics. More...

template<typename Ordinal , typename Packet >
void	broadcast (const Comm< Ordinal > &comm, const Serializer< Ordinal, Packet > &serializer, const int rootRank, const ArrayView< const Ptr< Packet > > &buffer)
	Broadcast array of objects that use reference semantics. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	broadcast (const Comm< Ordinal > &comm, const Serializer &serializer, const int rootRank, const Ordinal count, Packet buffer[])
	Broadcast array of objects that use value semantics using customized serializer. More...

template<typename Ordinal , typename Packet >
void	gather (const Packet sendBuf[], const Ordinal sendCount, Packet recvBuf[], const Ordinal recvCount, const int root, const Comm< Ordinal > &comm)
	Gather values from each process to the root process. More...

template<typename Ordinal , typename Packet >
void	gatherv (const Packet sendBuf[], const Ordinal sendCount, Packet recvBuf[], const Ordinal recvCounts[], const Ordinal displs[], const int root, const Comm< Ordinal > &comm)
	Gather arrays of possibly different lengths from each process to the root process. More...

template<typename Ordinal , typename Packet >
void	gatherAll (const Comm< Ordinal > &comm, const Ordinal sendCount, const Packet sendBuffer[], const Ordinal recvCount, Packet recvBuffer[])
	Gather array of objects that use value semantics from every process to every process. More...

template<typename Ordinal , typename Packet >
void	gatherAll (const Comm< Ordinal > &comm, const Serializer< Ordinal, Packet > &serializer, const Ordinal sendCount, const Packet const sendBuffer[], const Ordinal recvCount, Packet const recvBuffer[])
	Gather array of objects that use reference semantics from every process to every process. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	gatherAll (const Comm< Ordinal > &comm, const Serializer &serializer, const Ordinal sendCount, const Packet sendBuffer[], const Ordinal recvCount, Packet recvBuffer[])
	Gather array of objects that use value semantics from every process to every process using customized serializer. More...

template<typename Ordinal , typename Packet >
void	scatter (const Packet sendBuf[], const Ordinal sendCount, Packet recvBuf[], const Ordinal recvCount, const Ordinal root, const Comm< Ordinal > &comm)
	Wrapper for MPI_Scatter; scatter collective. More...

template<typename Ordinal , typename Packet >
void	reduce (const Packet sendBuf[], Packet recvBuf[], const Ordinal count, const EReductionType reductType, const Ordinal root, const Comm< Ordinal > &comm)
	Wrapper for MPI_Reduce; reduction to one process, using a built-in reduction operator selected by enum. More...

template<typename Ordinal , typename Packet >
void	reduceAll (const Comm< Ordinal > &comm, const ValueTypeReductionOp< Ordinal, Packet > &reductOp, const Ordinal count, const Packet sendBuffer[], Packet globalReducts[])
	Wrapper for MPI_Allreduce that takes a custom reduction operator. More...

template<typename Ordinal , typename Packet >
void	reduceAll (const Comm< Ordinal > &comm, const EReductionType reductType, const Ordinal count, const Packet sendBuffer[], Packet globalReducts[])
	Collective reduce all of array of objects using value semantics using a pre-defined reduction type. More...

template<typename Ordinal , typename Packet >
void	reduceAll (const Comm< Ordinal > &comm, const EReductionType reductType, const Packet &send, const Ptr< Packet > &globalReduct)
	Collective reduce all for single object using value semantics using a pre-defined reduction type. More...

template<typename Ordinal , typename Packet >
void	reduceAll (const Comm< Ordinal > &comm, const Serializer< Ordinal, Packet > &serializer, const ReferenceTypeReductionOp< Ordinal, Packet > &reductOp, const Ordinal count, const Packet const sendBuffer[], Packet const globalReducts[])
	Collective reduce all for array of objects using reference semantics. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	reduceAll (const Comm< Ordinal > &comm, const Serializer &serializer, const ValueTypeReductionOp< Ordinal, Packet > &reductOp, const Ordinal count, const Packet sendBuffer[], Packet globalReducts[])
	Collective reduce all of array of objects using value semantics using a user-defined reduction operator and customized serializer. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	reduceAll (const Comm< Ordinal > &comm, const Serializer &serializer, const EReductionType reductType, const Ordinal count, const Packet sendBuffer[], Packet globalReducts[])
	Collective reduce all of array of objects using value semantics using a pre-defined reduction type and customized serializer. More...

template<typename Ordinal , typename Packet >
void	scan (const Comm< Ordinal > &comm, const ValueTypeReductionOp< Ordinal, Packet > &reductOp, const Ordinal count, const Packet sendBuffer[], Packet scanReducts[])
	Scan/Reduce array of objects that use value semantics using a user-defined reduction operator. More...

template<typename Ordinal , typename Packet >
void	scan (const Comm< Ordinal > &comm, const EReductionType reductType, const Ordinal count, const Packet sendBuffer[], Packet scanReducts[])
	Scan/Reduce array of objects using value semantics using a predefined reduction type. More...

template<typename Ordinal , typename Packet >
void	scan (const Comm< Ordinal > &comm, const EReductionType reductType, const Packet &send, const Ptr< Packet > &scanReduct)
	Scan/Reduce single object using value semantics using a predefined reduction type. More...

template<typename Ordinal , typename Packet >
void	scan (const Comm< Ordinal > &comm, const Serializer< Ordinal, Packet > &serializer, const ReferenceTypeReductionOp< Ordinal, Packet > &reductOp, const Ordinal count, const Packet const sendBuffer[], Packet const scanReducts[])
	Scan/Reduce array of objects that use reference semantics using a user-defined reduction operator. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	scan (const Comm< Ordinal > &comm, const Serializer &serializer, const ValueTypeReductionOp< Ordinal, Packet > &reductOp, const Ordinal count, const Packet sendBuffer[], Packet scanReducts[])
	Scan/Reduce array of objects that use value semantics using a user-defined reduction operator and customized serializer. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	scan (const Comm< Ordinal > &comm, const Serializer &serializer, const EReductionType reductType, const Ordinal count, const Packet sendBuffer[], Packet scanReducts[])
	Scan/Reduce array of objects using value semantics using a predefined reduction type and customized serializer. More...

template<typename Ordinal , typename Packet >
void	send (const Comm< Ordinal > &comm, const Ordinal count, const Packet sendBuffer[], const int destRank)
	Send objects that use values semantics to another process. More...

template<typename Ordinal , typename Packet >
void	ssend (const Comm< Ordinal > &comm, const Ordinal count, const Packet sendBuffer[], const int destRank)
	Synchronously send objects that use values semantics to another process. More...

template<typename Ordinal , typename Packet >
void	send (const Comm< Ordinal > &comm, const Packet &send, const int destRank)
	Send a single object that use values semantics to another process. More...

template<typename Ordinal , typename Packet >
void	ssend (const Comm< Ordinal > &comm, const Packet &send, const int destRank)
	Synchronously send a single object that use values semantics to another process. More...

template<typename Ordinal , typename Packet >
void	send (const Comm< Ordinal > &comm, const Serializer< Ordinal, Packet > &serializer, const Ordinal count, const Packet *const sendBuffer[], const int destRank)
	Send objects that use reference semantics to another process. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	send (const Comm< Ordinal > &comm, const Serializer &serializer, const Ordinal count, const Packet sendBuffer[], const int destRank)
	Send objects that use values semantics to another process using customized serializer. More...

template<typename Ordinal , typename Packet >
int	receive (const Comm< Ordinal > &comm, const int sourceRank, const Ordinal count, Packet recvBuffer[])
	Receive objects that use values semantics from another process. More...

template<typename Ordinal , typename Packet >
int	receive (const Comm< Ordinal > &comm, const int sourceRank, Packet *recv)
	Receive a single object that use values semantics from another process. More...

template<typename Ordinal , typename Packet >
int	receive (const Comm< Ordinal > &comm, const Serializer< Ordinal, Packet > &serializer, const int sourceRank, const Ordinal count, Packet *const recvBuffer[])
	Receive objects that use reference semantics from another process. More...

template<typename Ordinal , typename Packet , typename Serializer >
int	receive (const Comm< Ordinal > &comm, const Serializer &serializer, const int sourceRank, const Ordinal count, Packet recvBuffer[])
	Receive objects that use values semantics from another process using customized serializer. More...

template<typename Ordinal , typename Packet >
void	readySend (const Comm< Ordinal > &comm, const ArrayView< const Packet > &sendBuffer, const int destRank)
	Ready-Send an array of objects that use values semantics to another process. More...

template<typename Ordinal , typename Packet >
void	readySend (const Comm< Ordinal > &comm, const Packet &send, const int destRank)
	Ready-Send a single object that use values semantics to another process. More...

template<typename Ordinal , typename Packet , typename Serializer >
void	readySend (const Comm< Ordinal > &comm, const Serializer &serializer, const ArrayView< const Packet > &sendBuffer, const int destRank)
	Ready-Send an array of objects that use values semantics to another process using customized serializer. More...

template<typename Ordinal , typename Packet >
RCP< CommRequest< Ordinal > >	isend (const Comm< Ordinal > &comm, const ArrayRCP< const Packet > &sendBuffer, const int destRank)
	Send objects that use values semantics to another process. More...

template<typename Ordinal , typename Packet >
RCP< CommRequest< Ordinal > >	isend (const Comm< Ordinal > &comm, const RCP< const Packet > &send, const int destRank)
	Send a single object that use values semantics to another process. More...

template<typename Ordinal , typename Packet , typename Serializer >
RCP< CommRequest< Ordinal > >	isend (const Comm< Ordinal > &comm, const Serializer &serializer, const ArrayRCP< const Packet > &sendBuffer, const int destRank)
	Send objects that use values semantics to another process using customized serializer. More...

template<typename Ordinal , typename Packet >
RCP< CommRequest< Ordinal > >	ireceive (const Comm< Ordinal > &comm, const ArrayRCP< Packet > &recvBuffer, const int sourceRank)
	Receive one or more objects (that use values semantics) from another process. More...

template<typename Ordinal , typename Packet >
RCP< CommRequest< Ordinal > >	ireceive (const Comm< Ordinal > &comm, const RCP< Packet > &recv, const int sourceRank)
	Receive one object (that uses values semantics) from another process. More...

template<typename Ordinal , typename Packet , typename Serializer >
RCP< CommRequest< Ordinal > >	ireceive (const Comm< Ordinal > &comm, const Serializer &serializer, const ArrayRCP< Packet > &recvBuffer, const int sourceRank)
	Send objects that use values semantics to another process using customized serializer. More...

template<typename Ordinal >
void	waitAll (const Comm< Ordinal > &comm, const ArrayView< RCP< CommRequest< Ordinal > > > &requests)
	Wait for an array of Teuchos::CommRequest objects. More...

template<typename Ordinal >
void	waitAll (const Comm< Ordinal > &comm, const ArrayView< RCP< CommRequest< Ordinal > > > &requests, const ArrayView< RCP< CommStatus< Ordinal > > > &statuses)
	Wait on one or more communication requests, and return their statuses. More...

template<typename Ordinal >
RCP< CommStatus< Ordinal > >	wait (const Comm< Ordinal > &comm, const Ptr< RCP< CommRequest< Ordinal > > > &request)
	Wait on a single communication request, and return its status. More...

Related Functions inherited from Teuchos::Describable
DescribableStreamManipulatorState	describe (const Describable &describable, const EVerbosityLevel verbLevel=Describable::verbLevel_default)
	Describable output stream manipulator. More...

std::ostream &	operator<< (std::ostream &os, const DescribableStreamManipulatorState &d)
	Output stream operator for Describable manipulator. More...

Additional Inherited Members
Static Public Attributes inherited from Teuchos::Describable
static const EVerbosityLevel	verbLevel_default = VERB_DEFAULT
	Default value for the `verbLevel` argument of describe(). More...

Detailed Description

template<class OrdinalType>
class Teuchos::Comm< OrdinalType >

Abstract interface for distributed-memory communication.

Template Parameters

Ordinal Type of indices used for communication.

What is Comm?

This class is Teuchos' interface to distributed-memory communication between one or more parallel processes. It presents an interface very much like that of MPI (the Message Passing Interface). Teuchos provides two implementations of Comm:

An MPI (Message Passing Interface) implementation, MpiComm
A "serial" implementation, SerialComm, that only has one process

Comm is an abstract interface. You cannot create a Comm directly. You have to create one of the subclasses. The normal way to handle a Comm is to pass it around using RCP (a reference-counted "smart" pointer). For example:

// Make a Comm.  This one happens to wrap MPI_COMM_WORLD.
RCP<const Comm<int> > comm = rcp (new MpiComm (MPI_COMM_WORLD));
// Equivalent of MPI_Comm_rank
const int myRank = comm->getRank ();
// Equivalent of MPI_Comm_size
const int numProcs = comm->getSize ();
// Equivalent of MPI_Comm_barrier
comm->barrier ();

Comm's communication methods that actually send or receive data accept that data as an array of char. You should never call these methods directly. Instead, you should use the nonmember "helper" functions in Teuchos_CommHelpers.hpp. These methods are templated on the Packet type, that is, the type of data you want to send or receive. See the example below.

Treat <tt>RCP<const Comm<int> ></tt> like an opaque handle

You should consider an RCP<const Comm<int> > as equivalent to the MPI_Comm opaque handle, except that the RCP also does reference counting to ensure memory safety when using the same communicator in different parts of the code. That is, copying the RCP does not create a new communicator; the following two codes do about the same thing, except with a different syntax (and reference counting in the second code).

Raw MPI_Comm handles:

MPI_Comm comm = ...;
// sameComm is THE SAME COMMUNICATOR as comm.
MPI_Comm sameComm = comm;

Reference-counted pointers to Comm:

RCP<const Comm<int> > comm = ...;
// *sameComm is THE SAME COMMUNICATOR as *comm.
RCP<const Comm<int> > sameComm = comm;

If you want to make a "new communicator" rather than just "copy the handle," you should call the duplicate() method. This has the same behavior as MPI_Comm_dup (which see).

The "reference counting" feature means that the subclass of Comm will take care of freeing the underlying MPI_Comm (and any other data structures it may use) by calling MPI_Comm_free if necessary, once the reference count of the RCP goes to zero.

Warning: Do not pass around subclasses of Comm by value! Comm or its subclasses by themselves do not have handle semantics. Their copy constructors likely do not behave as you would expect if the classes had handle semantics.

How do I make a Comm?

Comm works whether or not you have build Trilinos with MPI support. If you want to make a "default" Comm that is the equivalent of MPI_COMM_WORLD, but you don't know if your Trilinos with MPI enabled, you may use GlobalMPISession to call MPI_Init if necessary, and DefaultComm to "get a default communicator." For example: int main (int argc, char* argv[]) { using Teuchos::Comm; using Teuchos::DefaultComm; using Teuchos::RCP;

// This replaces the call to MPI_Init. If you didn't // build with MPI, this doesn't call MPI functions. Teuchos::GlobalMPISesssion session (&argc, &argv, NULL); // comm is the equivalent of MPI_COMM_WORLD. RCP<const Comm<int> > comm = DefaultComm<int>::getComm ();

// ... use comm in your code as you would use MPI_COMM_WORLD ...

// We don't need to call MPI_Finalize, since the // destructor of GlobalMPISession does that for us. return EXIT_SUCCESS; } This code works whether or not you built Trilinos with MPI support. It is not necessary to use GlobalMPISession, but it's useful so you don't have to remember to call MPI_Finalize. If you don't want to use GlobalMPISession, you can still call DefaultComm<int>::getComm(), though you must have called MPI_Init first if you build Trilinos with MPI support. Furthermore, if you know MPI is present, you don't need to use DefaultComm. You may simply pass MPI_COMM_WORLD directly to MpiComm, like this:

RCP<const Comm<int> > comm = rcp (new MpiComm (MPI_COMM_WORLD));

You may also pass an arbitrary MPI_Comm directly into MpiComm's constructor, though you are responsible for freeing it after use (via MPI_Comm_free) if necessary. You may automate the freeing of your MPI_Comm by using OpaqueWrapper (which see).

How do I use Comm?

As we mentioned above, for communication of data with Comm, you you should use the nonmember "helper" functions in Teuchos_CommHelpers.hpp. These methods are templated on the Packet type, that is, the type of data you want to send or receive. For example, suppose you have two processes (with ranks 0 and 1, respectively), and you want to send an array of 10 double from Process 0 to Process 1. Both processes have defined RCP<const Comm<int> > comm as above. Here is the code on Process 0:

const int count = 10; // Send 10 doubles
double values[10] = ...;
const int destinationRank = 1; // Send to Process 1
// You may be able to omit the template arguments of 'send' here.
Teuchos::send<int, double> (*comm, 10, values, destinationRank);

Here is the code on Process 1:

const int count = 10; // Receive 10 doubles
double values[10]; // Will be overwritten by receive
const int sourceRank = 0; // Receive from Process 0
// You may be able to omit the template arguments of 'receive' here.
Teuchos::receive<int, double> (*comm, sourceRank, 10, values);

Please refer to the documentation in Teuchos_CommHelpers.hpp for more details.

Former documentation

This interface is templated on the ordinal type but only deals with buffers of untyped data represented as arrays char type. All reduction operations that are initiated by the concreate communicator object are performed by user-defined ReductOpBase objects. It is the responsibility of the ReductOpBase object to know what the currect data type is, to perform casts or serializations/unserializations to and from char[] buffers, and to know how to reduce the objects correctly. It is strictly up to the client to correctly convert data types to char[] arrays but there is a great deal of helper code to make this easy and safe.

Definition at line 85 of file Teuchos_Comm.hpp.

Constructor & Destructor Documentation

template<class OrdinalType>

virtual Teuchos::Comm< OrdinalType >::~Comm ( )

inlinevirtual

Destructor, declared virtual for safety of derived classes.

Definition at line 323 of file Teuchos_Comm.hpp.

Member Function Documentation

template<class OrdinalType>

virtual int Teuchos::Comm< OrdinalType >::getTag ( ) const

pure virtual

The current tag.

Warning: This method is ONLY for use by Teuchos developers. Users should not depend on the interface of this method. It may change or disappear at any time without warning.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual int Teuchos::Comm< OrdinalType >::getRank ( ) const

pure virtual

Returns the rank of this process.

Postconditions:

0 <= return && return < this->getSize()

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual int Teuchos::Comm< OrdinalType >::getSize ( ) const

pure virtual

Returns the number of processes that make up this communicator.

Postconditions:

return > 0

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::barrier ( ) const

pure virtual

Pause every process in *this communicator until all the processes reach this point.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::broadcast	(	const int	rootRank,
		const Ordinal	bytes,
		char	buffer[]
	)		const

pure virtual

Broadcast values from the root process to the slave processes.

Parameters

rootRank	[in] The rank of the root process.
count	[in] The number of bytes in `buffer[]`.
buffer	[in/out] Array (length `bytes`) of packed data. Must be set on input on the root processes with rank `root`. On output, each processs, including the root process contains the data.

Preconditions:

0 <= rootRank && rootRank < this->getSize()

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::gather	(	const Ordinal	sendBytes,
		const char	sendBuffer[],
		const Ordinal	recvBytes,
		char	recvBuffer[],
		const int	root
	)		const

pure virtual

Gather values from all processes to the root process.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::gatherAll	(	const Ordinal	sendBytes,
		const char	sendBuffer[],
		const Ordinal	recvBytes,
		char	recvBuffer[]
	)		const

pure virtual

Gather values from each process to collect on all processes.

Parameters

sendBytes	[in] Number of entires in `sendBuffer[]` on input.
sendBuffer	[in] Array (length `sendBytes`) of data being sent from each process.
recvBytes	[in] Number of entires in `recvBuffer[]` which must be equal to `sendBytes*this->getSize()`. This field is just here for debug checking.
recvBuffer	[out] Array (length `recvBytes`) of all of the entires sent from each processes. Specifically, `recvBuffer[sendBytes*j+i]`, for `j=0...this->getSize()-1` and `i=0...sendBytes-1`, is the entry `sendBuffer[i]` from process with rank `j`.

Preconditions:

recvBytes==sendBytes*this->getSize()

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::reduceAll	(	const ValueTypeReductionOp< Ordinal, char > &	reductOp,
		const Ordinal	bytes,
		const char	sendBuffer[],
		char	globalReducts[]
	)		const

pure virtual

Global reduction.

Parameters

reductOp	[in] The user-defined reduction operation
bytes	[in] The length of the buffers `sendBuffer[]` and `globalReducts[]`.
sendBuffer	[in] Array (length `bytes`) of the data contributed from each process.
globalReducts	[out] Array (length `bytes`) of the global reduction from each process.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::scan	(	const ValueTypeReductionOp< Ordinal, char > &	reductOp,
		const Ordinal	bytes,
		const char	sendBuffer[],
		char	scanReducts[]
	)		const

pure virtual

Scan reduction.

Parameters

reductOp	[in] The user-defined reduction operation
bytes	[in] The length of the buffers `sendBuffer[]` and `scanReducts[]`.
sendBuffer	[in] Array (length `bytes`) of the data contributed from each process.
scanReducts	[out] Array (length `bytes`) of the reduction up to and including this process.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::send	(	const Ordinal	bytes,
		const char	sendBuffer[],
		const int	destRank
	)		const

pure virtual

Possibly blocking send of data from this process to another process.

This routine does not return until you can reuse the send buffer. Whether this routine blocks depends on whether the MPI implementation buffers.

Parameters

bytes	[in] The number of bytes of data being passed between processes.
sendBuffer	[in] Array (length `bytes`) of data being sent from this process. This buffer can be immediately destroyed or reused as soon as the function exits (that is why this function is "blocking").
destRank	[in] The rank of the process to receive the data.

Preconditions:

0 <= destRank && destRank < this->getSize()
destRank != this->getRank()

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::send	(	const Ordinal	bytes,
		const char	sendBuffer[],
		const int	destRank,
		const int	tag
	)		const

pure virtual

Variant of send() that takes a tag.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::ssend	(	const Ordinal	bytes,
		const char	sendBuffer[],
		const int	destRank
	)		const

pure virtual

Always blocking send of data from this process to another process.

This routine blocks until the matching receive posts. After it returns, you are allowed to reuse the send buffer.

Parameters

bytes	[in] The number of bytes of data being passed between processes.
sendBuffer	[in] Array (length `bytes`) of data being sent from this process. This buffer can be immediately destroyed or reused as soon as the function exits (that is why this function is "blocking").
destRank	[in] The rank of the process to receive the data.

Preconditions:

0 <= destRank && destRank < this->getSize()
destRank != this->getRank()

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::ssend	(	const Ordinal	bytes,
		const char	sendBuffer[],
		const int	destRank,
		const int	tag
	)		const

pure virtual

Variant of ssend() that takes a message tag.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual int Teuchos::Comm< OrdinalType >::receive	(	const int	sourceRank,
		const Ordinal	bytes,
		char	recvBuffer[]
	)		const

pure virtual

Blocking receive of data from this process to another process.

Parameters

sourceRank	[in] The rank of the process to receive the data from. If `sourceRank < 0` then data will be received from any process.
bytes	[in] The number of bytes of data being passed between processes.
recvBuffer	[out] Array (length `bytes`) of data being received from this process. This buffer can be immediately used to access the data as soon as the function exits (that is why this function is "blocking").

Preconditions:

[sourceRank >= 0] sourceRank < this->getSize()
sourceRank != this->getRank()


Returns
Returns the senders rank.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::readySend	(	const ArrayView< const char > &	sendBuffer,
		const int	destRank
	)		const

pure virtual

Ready send of data from this process to another process.

Parameters

sendBuffer	[in] The data to be sent.
destRank	[in] The rank of the process to receive the data.

Preconditions:

0 <= destRank && destRank < this->getSize()
destRank != this->getRank()

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::readySend	(	const Ordinal	bytes,
		const char	sendBuffer[],
		const int	destRank,
		const int	tag
	)		const

pure virtual

Variant of readySend() that accepts a message tag.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP<CommRequest<Ordinal> > Teuchos::Comm< OrdinalType >::isend	(	const ArrayView< const char > &	sendBuffer,
		const int	destRank
	)		const

pure virtual

Non-blocking send.

Parameters

sendBuffer	[in] The data buffer to be sent.
destRank	[in] The rank of the process to receive the data.

Preconditions:

0 <= destRank && destRank < this->getSize()
destRank != this->getRank()

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP<CommRequest<Ordinal> > Teuchos::Comm< OrdinalType >::isend	(	const ArrayView< const char > &	sendBuffer,
		const int	destRank,
		const int	tag
	)		const

pure virtual

Variant of isend() that takes a tag.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP<CommRequest<Ordinal> > Teuchos::Comm< OrdinalType >::ireceive	(	const ArrayView< char > &	recvBuffer,
		const int	sourceRank
	)		const

pure virtual

Non-blocking receive.

Parameters

recvBuffer	[out] The location for storing the received data.
sourceRank	[in] The rank of the process to receive the data from. If `sourceRank < 0` then data will be received from any process.

Preconditions:

[sourceRank >= 0] sourceRank < this->getSize()
sourceRank != this->getRank()


Returns
Returns the senders rank.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP<CommRequest<Ordinal> > Teuchos::Comm< OrdinalType >::ireceive	(	const ArrayView< char > &	recvBuffer,
		const int	sourceRank,
		const int	tag
	)		const

pure virtual

Variant of ireceive that takes a tag.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::waitAll ( const ArrayView< RCP< CommRequest< Ordinal > > > & requests ) const

pure virtual

Wait on a set of communication requests.

Preconditions:

requests.size() > 0

Postconditions:

is_null(request[i])) for i=0...requests.size()-1

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual void Teuchos::Comm< OrdinalType >::waitAll	(	const ArrayView< RCP< CommRequest< Ordinal > > > &	requests,
		const ArrayView< RCP< CommStatus< Ordinal > > > &	statuses
	)		const

pure virtual

Wait on communication requests, and return their statuses.

Precondition: requests.size() == statuses.size(); For i in 0, 1, ..., requests.size()-1, requests[i] is either null or requests[i] was returned by an ireceive() or isend().

Postcondition: For i in 0, 1, ..., requests.size()-1, requests[i].is_null() is true.

Parameters

requests	[in/out] On input: the requests on which to wait. On output: all set to null.
statuses	[out] The status results of waiting on the requests.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP<CommStatus<Ordinal> > Teuchos::Comm< OrdinalType >::wait ( const Ptr< RCP< CommRequest< Ordinal > > > & request ) const

pure virtual

Wait on a single communication request, and return its status.

Parameters

request [in/out] On input: request is not null, and *request is either null (in which case this function does nothing and returns null) or an RCP of a valid CommRequest instance representing an outstanding communication request. On output: If the communication request completed successfully, we set *request to null, indicating that the request has completed. (This helps prevent common bugs like trying to complete the same request twice.)

Returns: If *request is null, this method returns null. Otherwise this method returns a CommStatus instance representing the result of completing the request. In the case of a nonblocking receive request, you can query the CommStatus instance for the process ID of the sending process. (This is useful for receiving from any process via MPI_ANY_SOURCE.)

Precondition: !is_null(request) (that is, the Ptr is not null).

Postcondition: is_null(*request) (that is, the RCP is null).

This function blocks until the communication operation associated with the CommRequest object has completed.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP< Comm > Teuchos::Comm< OrdinalType >::duplicate ( ) const

pure virtual

Duplicate this communicator.

Make a copy of this communicator with a duplicate communication space. Note that the returned communicator has the same properties (including process ranks, attributes and topologies) as this communicator, but is distinct from the original. "Distinct" means that if you send a message on the original communicator, you can't receive it on the new one, and vice versa. The new communicator represents a separate message space. This has the same semantics as MPI_Comm_dup. (In fact, the subclass MpiComm implements this using MPI_Comm_dup.)

Most users don't want to do this. The duplicate() method returns a new communicator. In MPI terms, it is a different MPI_Comm. If you want a shallow copy of the handle, you should pass the Comm<Ordinal> around by const pointer, like this:


RCP<const Comm<int> > comm = ...; // my original communicator
// ... do some stuff with comm ...
// Make a shallow copy.
RCP<const Comm<int> > diffHandleSameComm = comm;
// ... do some stuff with diffHandleSameComm ...
 This behaves the same as the following "raw MPI" code: 
MPI_Comm comm = ...; // my original communicator
// ... do some stuff with comm ...
// Make a shallow copy.
MPI_Comm diffHandleSameComm = comm;
// ... do some stuff with diffHandleSameComm ...

The subclass of Comm ensures that the "raw" MPI handle is freed only after the last reference to it by a subclass instance disappears. (It does reference counting underneath.)

Please, please do not invoke the copy constructor or assignment operator of Comm. Of course it's not legal to do that anyway, because Comm is pure virtual. However, even if you could do it, you must never do this! For example, do not do this:


RCP<const Comm<int> > comm = ...; // my original communicator
// ... do some stuff with comm ...
// DO NOT DO THIS, EVER!!!  THIS IS VERY BAD!!!
RCP<const Comm<int> > badComm (new Comm<int> (*comm));
 and do not do this: 
RCP<const Comm<int> > comm = ...; // my original communicator
// ... do some stuff with comm ...
// DO NOT DO THIS, EITHER!!!  THIS IS JUST AS BAD!!!
RCP<const Comm<int> > badComm = rcp (new Comm<int> (*comm));

This is bad because it ignores the subclass' data. Depending on the subclass of Comm that you are actually using, it may be appropriate to invoke the copy constructor or assignment operator of the specific subclass, but never those of Comm itself.

Users are not responsible for freeing the returned communicator. The destructor of the subclass of Comm handles that itself.

In an MPI implementation, the returned communicator is created using MPI_Comm_dup, with the resulting semantic implications.


Returns
A new communicator.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP<Comm> Teuchos::Comm< OrdinalType >::split	(	const int	color,
		const int	key
	)		const

pure virtual

Split a communicator into subcommunicators based on color and key.

Partition this communicator into multiple disjoint groups, and return the communicator corresponding to the group to which this process belongs. There will be as many groups as there are globally many distinct values for the color parameter. Within each subset of the partition, the ranks will be ordered according to the key value each process passed for the key parameter. If multiple processes pass the same value for key, then they will be ordered according to their rank in the original communicator. To return a valid communicator, this function requires a nonnegative value for color. If color is negative, this method will return a null communicator.

This method must be called as a collective on all processes in this communicator. That is, if this method is called at all, it must be called on all processes in the communicator.

Users are not responsible for freeing the returned communicator. The destructor of the subclass of Comm handles that itself.

In an MPI implementation, the returned communicator is created using MPI_Comm_split, with the resulting semantic implications.

Parameters

color	[in] An integer representing the color for the local rank. In the MPI implementation, if this is negative, MPI_Comm_split gets `MPI_UNDEFINED` as the color.
key	[in] A key value to order processes of the same color. In the MPI implementation, this is passed directly to MPI_Comm_split.

Returns: A partitioned communicator.

Implemented in Teuchos::SerialComm< Ordinal >.

template<class OrdinalType>

virtual RCP<Comm> Teuchos::Comm< OrdinalType >::createSubcommunicator ( const ArrayView< const int > & ranks ) const

pure virtual

Create a subcommunicator containing the specified processes.

Create and return a subcommunicator of this communicator. The subcommunicator contains the processes in this communicator with the given ranks, in which they are listed in the input vector. Processes whose ranks are not included in the input vector will be given a null communicator.

This method must be called as a collective on all processes in this communicator. That is, if this method is called at all, it must be called on all processes in the communicator.

Users are not responsible for freeing the returned communicator. The destructor of the subclass of Comm handles that itself.

In an MPI implementation, the subcommunicator is created using MPI_Comm_create, with the resulting semantic implications.

Parameters

ranks The ranks of the processes to include in the subcommunicator.

Returns: The subcommunicator.

Implemented in Teuchos::SerialComm< Ordinal >.

Friends And Related Function Documentation

template<class OrdinalType>

enum EReductionType

Teuchos' Comm class wraps MPI (the Message Passing Interface for distributed-memory parallel programming). If you do not have MPI, it imitates MPI's functionality, as if you were running with a single "parallel" process. This means that Teuchos must wrap a subset of MPI's functionality, so that it can build without MPI.

Comm provides wrappers for MPI_Reduce, MPI_Allreduce, and other collectives that take a reduction operator MPI_Op. Teuchos wraps MPI_Op in two different ways. The first way is this enum, which lets users pick from a set of common predefined MPI_Op. The second way is through Teuchos' wrappers for custom MPI_Op, namely ValueTypeReductionOp and ValueTypeReductionOp. Most users should find the reduction operators below sufficient.

Enumerator
REDUCE_SUM	Sum.
REDUCE_MIN	Min.
REDUCE_MAX	Max.
REDUCE_AND	Logical AND.
REDUCE_BOR	Bitwise OR.

Definition at line 71 of file Teuchos_EReductionType.hpp.

template<typename Ordinal >

int rank ( const Comm< Ordinal > & comm )

template<typename Ordinal >

int size ( const Comm< Ordinal > & comm )

Examples:: ArrayRCP_test.cpp.

template<typename Ordinal >

void barrier ( const Comm< Ordinal > & comm )

template<typename Ordinal , typename Packet >

void broadcast	(	const Comm< Ordinal > &	comm,
		const int	rootRank,
		const Ordinal	count,
		Packet	buffer[]
	)

template<typename Ordinal , typename Packet >

void broadcast	(	const Comm< Ordinal > &	comm,
		const int	rootRank,
		const ArrayView< Packet > &	buffer
	)

template<typename Ordinal , typename Packet >

void broadcast	(	const Comm< Ordinal > &	comm,
		const int	rootRank,
		Packet *	object
	)

template<typename Ordinal , typename Packet >

void broadcast	(	const Comm< Ordinal > &	comm,
		const int	rootRank,
		const Ptr< Packet > &	object
	)

template<typename Ordinal , typename Packet >

void broadcast	(	const Comm< Ordinal > &	comm,
		const Serializer< Ordinal, Packet > &	serializer,
		const int	rootRank,
		const Ordinal	count,
		Packet *const	buffer[]
	)

template<typename Ordinal , typename Packet >

void broadcast	(	const Comm< Ordinal > &	comm,
		const Serializer< Ordinal, Packet > &	serializer,
		const int	rootRank,
		const ArrayView< const Ptr< Packet > > &	buffer
	)

template<typename Ordinal , typename Packet , typename Serializer >

void broadcast	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const int	rootRank,
		const Ordinal	count,
		Packet	buffer[]
	)

template<typename Ordinal , typename Packet >

void gather	(	const Packet	sendBuf[],
		const Ordinal	sendCount,
		Packet	recvBuf[],
		const Ordinal	recvCount,
		const int	root,
		const Comm< Ordinal > &	comm
	)

This wraps MPI_Gather in an MPI build, when Comm implements MpiComm.

template<typename Ordinal , typename Packet >

void gatherv	(	const Packet	sendBuf[],
		const Ordinal	sendCount,
		Packet	recvBuf[],
		const Ordinal	recvCounts[],
		const Ordinal	displs[],
		const int	root,
		const Comm< Ordinal > &	comm
	)

This wraps MPI_Gatherv in an MPI build, when Comm implements MpiComm.

template<typename Ordinal , typename Packet >

void gatherAll	(	const Comm< Ordinal > &	comm,
		const Ordinal	sendCount,
		const Packet	sendBuffer[],
		const Ordinal	recvCount,
		Packet	recvBuffer[]
	)

template<typename Ordinal , typename Packet >

void gatherAll	(	const Comm< Ordinal > &	comm,
		const Serializer< Ordinal, Packet > &	serializer,
		const Ordinal	sendCount,
		const Packet *const	sendBuffer[],
		const Ordinal	recvCount,
		Packet *const	recvBuffer[]
	)

template<typename Ordinal , typename Packet , typename Serializer >

void gatherAll	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const Ordinal	sendCount,
		const Packet	sendBuffer[],
		const Ordinal	recvCount,
		Packet	recvBuffer[]
	)

template<typename Ordinal , typename Packet >

void scatter	(	const Packet	sendBuf[],
		const Ordinal	sendCount,
		Packet	recvBuf[],
		const Ordinal	recvCount,
		const Ordinal	root,
		const Comm< Ordinal > &	comm
	)

Template Parameters

Ordinal	The template parameter of Comm. Should always be `int` unless you REALLY know what you are doing.
Packet	The type of the thing this operation communicates. For this particular overload of scatter(), `Packet` must have "value semantics" and must not require a custom `Serializer`. Built-in types and structs thereof are generally OK here.

If Comm is an MpiComm, then this wraps MPI_Scatter(). This function is a collective operation over the input communicator.

Parameters

sendBuf	[in] Array of Packet things to scatter out. This may NOT alias `recvBuf`. This is ONLY read on the root process of the collective.
sendCount	The number of `Packet` things for the root process to send to each process in the input communicator.
recvBuf	[out] Array of `recvCount*comm.getSize()` Packet things to receive. This may NOT alias `sendBuf`.
recvCount	[in] Number of Packet things to receive from each process.
root	[in] Rank of the process from which to scatter (the root of the scatter operation). The rank is relative to the input communicator.
comm	[in] The communicator over which to scatter.

Definition at line 271 of file Teuchos_CommHelpers.hpp.

template<typename Ordinal , typename Packet >

void reduce	(	const Packet	sendBuf[],
		Packet	recvBuf[],
		const Ordinal	count,
		const EReductionType	reductType,
		const Ordinal	root,
		const Comm< Ordinal > &	comm
	)

Template Parameters

Ordinal	The template parameter of Comm. Should always be `int` unless you REALLY know what you are doing.
Packet	The type of the thing this operation communicates. For this particular overload of reduce(), `Packet` must have "value semantics" and must not require a custom `Serializer`. Built-in types and structs thereof are generally OK here.

If Comm is an MpiComm, then this wraps MPI_Reduce(). This function is a collective operation over the input communicator.

Parameters

sendBuf	[in] Array of `count` Packet things to send. This may NOT alias `recvBuf`.
recvBuf	[in] Array of `count` Packet reduction results. This may NOT alias `sendBuf`.
count	[in] Number of entries in the sendBuf and recvBuf arrays.
reductType	[in] Type of reduction operation. Valid values include REDUCE_SUM, REDUCE_MIN, REDUCE_MAX, and REDUCE_AND. See the documentation of the EReductionType enum for details.
root	[in] Rank of the process on which to receive the reduction result. The rank is relative to the input communicator.
comm	[in] The communicator over which to reduce.

template<typename Ordinal , typename Packet >

void reduceAll	(	const Comm< Ordinal > &	comm,
		const ValueTypeReductionOp< Ordinal, Packet > &	reductOp,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	globalReducts[]
	)

Template Parameters

Ordinal	The template parameter of Comm. Should always be `int` unless you REALLY know what you are doing.
Packet	The type of the thing this operation communicates. For this particular overload of reduce(), `Packet` must have "value semantics" and must not require a custom `Serializer`. Built-in types and structs thereof are generally OK here.

If Comm is an MpiComm, then this wraps MPI_Allreduce(). This function is a collective operation over the input communicator.

Parameters

comm	[in] The communicator over which to reduce.
reductOp	[in] The custom reduction operator.
count	[in] Number of entries in the `sendBuffer` and `globalReducts` arrays.
sendBuffer	[in] Array of `count` `Packet` things to send. This may NOT alias `globalReducts`.
globalReducts	[in] Array of `count` `Packet` reduction results. This may NOT alias `recvBuf`.

template<typename Ordinal , typename Packet >

void reduceAll	(	const Comm< Ordinal > &	comm,
		const EReductionType	reductType,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	globalReducts[]
	)

template<typename Ordinal , typename Packet >

void reduceAll	(	const Comm< Ordinal > &	comm,
		const EReductionType	reductType,
		const Packet &	send,
		const Ptr< Packet > &	globalReduct
	)

template<typename Ordinal , typename Packet >

void reduceAll	(	const Comm< Ordinal > &	comm,
		const Serializer< Ordinal, Packet > &	serializer,
		const ReferenceTypeReductionOp< Ordinal, Packet > &	reductOp,
		const Ordinal	count,
		const Packet *const	sendBuffer[],
		Packet *const	globalReducts[]
	)

template<typename Ordinal , typename Packet , typename Serializer >

void reduceAll	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const ValueTypeReductionOp< Ordinal, Packet > &	reductOp,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	globalReducts[]
	)

template<typename Ordinal , typename Packet , typename Serializer >

void reduceAll	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const EReductionType	reductType,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	globalReducts[]
	)

template<typename Ordinal , typename Packet >

void scan	(	const Comm< Ordinal > &	comm,
		const ValueTypeReductionOp< Ordinal, Packet > &	reductOp,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	scanReducts[]
	)

template<typename Ordinal , typename Packet >

void scan	(	const Comm< Ordinal > &	comm,
		const EReductionType	reductType,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	scanReducts[]
	)

template<typename Ordinal , typename Packet >

void scan	(	const Comm< Ordinal > &	comm,
		const EReductionType	reductType,
		const Packet &	send,
		const Ptr< Packet > &	scanReduct
	)

template<typename Ordinal , typename Packet >

void scan	(	const Comm< Ordinal > &	comm,
		const Serializer< Ordinal, Packet > &	serializer,
		const ReferenceTypeReductionOp< Ordinal, Packet > &	reductOp,
		const Ordinal	count,
		const Packet *const	sendBuffer[],
		Packet *const	scanReducts[]
	)

template<typename Ordinal , typename Packet , typename Serializer >

void scan	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const ValueTypeReductionOp< Ordinal, Packet > &	reductOp,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	scanReducts[]
	)

template<typename Ordinal , typename Packet , typename Serializer >

void scan	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const EReductionType	reductType,
		const Ordinal	count,
		const Packet	sendBuffer[],
		Packet	scanReducts[]
	)

template<typename Ordinal , typename Packet >

void send	(	const Comm< Ordinal > &	comm,
		const Ordinal	count,
		const Packet	sendBuffer[],
		const int	destRank
	)

template<typename Ordinal , typename Packet >

void ssend	(	const Comm< Ordinal > &	comm,
		const Ordinal	count,
		const Packet	sendBuffer[],
		const int	destRank
	)

template<typename Ordinal , typename Packet >

void send	(	const Comm< Ordinal > &	comm,
		const Packet &	send,
		const int	destRank
	)

template<typename Ordinal , typename Packet >

void ssend	(	const Comm< Ordinal > &	comm,
		const Packet &	send,
		const int	destRank
	)

template<typename Ordinal , typename Packet >

void send	(	const Comm< Ordinal > &	comm,
		const Serializer< Ordinal, Packet > &	serializer,
		const Ordinal	count,
		const Packet *const	sendBuffer[],
		const int	destRank
	)

NOTE: Not implemented yet!

template<typename Ordinal , typename Packet , typename Serializer >

void send	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const Ordinal	count,
		const Packet	sendBuffer[],
		const int	destRank
	)

template<typename Ordinal , typename Packet >

int receive	(	const Comm< Ordinal > &	comm,
		const int	sourceRank,
		const Ordinal	count,
		Packet	recvBuffer[]
	)

template<typename Ordinal , typename Packet >

int receive	(	const Comm< Ordinal > &	comm,
		const int	sourceRank,
		Packet *	recv
	)

template<typename Ordinal , typename Packet >

int receive	(	const Comm< Ordinal > &	comm,
		const Serializer< Ordinal, Packet > &	serializer,
		const int	sourceRank,
		const Ordinal	count,
		Packet *const	recvBuffer[]
	)

template<typename Ordinal , typename Packet , typename Serializer >

int receive	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const int	sourceRank,
		const Ordinal	count,
		Packet	recvBuffer[]
	)

template<typename Ordinal , typename Packet >

void readySend	(	const Comm< Ordinal > &	comm,
		const ArrayView< const Packet > &	sendBuffer,
		const int	destRank
	)

template<typename Ordinal , typename Packet >

void readySend	(	const Comm< Ordinal > &	comm,
		const Packet &	send,
		const int	destRank
	)

template<typename Ordinal , typename Packet , typename Serializer >

void readySend	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const ArrayView< const Packet > &	sendBuffer,
		const int	destRank
	)

template<typename Ordinal , typename Packet >

RCP< CommRequest< Ordinal > > isend	(	const Comm< Ordinal > &	comm,
		const ArrayRCP< const Packet > &	sendBuffer,
		const int	destRank
	)

template<typename Ordinal , typename Packet >

RCP< CommRequest< Ordinal > > isend	(	const Comm< Ordinal > &	comm,
		const RCP< const Packet > &	send,
		const int	destRank
	)

template<typename Ordinal , typename Packet , typename Serializer >

RCP< CommRequest< Ordinal > > isend	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const ArrayRCP< const Packet > &	sendBuffer,
		const int	destRank
	)

template<typename Ordinal , typename Packet >

RCP< CommRequest< Ordinal > > ireceive	(	const Comm< Ordinal > &	comm,
		const ArrayRCP< Packet > &	recvBuffer,
		const int	sourceRank
	)

Parameters

comm	[in] The communicator.
recvBuffer	[out] The buffer into which to receive the data.
sourceRank	[in] The rank of the sending process. A negative source rank means that this will accept an incoming message from any process on the given communicator. (This is the equivalent of MPI_ANY_SOURCE.)

template<typename Ordinal , typename Packet >

RCP< CommRequest< Ordinal > > ireceive	(	const Comm< Ordinal > &	comm,
		const RCP< Packet > &	recv,
		const int	sourceRank
	)

Parameters

comm	[in] The communicator.
recv	[out] The buffer into which to receive the object.
sourceRank	[in] The rank of the sending process. A negative source rank means that this will accept an incoming message from any process on the given communicator.

Note: To implementers: A negative source rank is the equivalent of MPI_ANY_SOURCE, if the given Comm is an MpiComm.

template<typename Ordinal , typename Packet , typename Serializer >

RCP< CommRequest< Ordinal > > ireceive	(	const Comm< Ordinal > &	comm,
		const Serializer &	serializer,
		const ArrayRCP< Packet > &	recvBuffer,
		const int	sourceRank
	)

template<typename Ordinal >

void waitAll	(	const Comm< Ordinal > &	comm,
		const ArrayView< RCP< CommRequest< Ordinal > > > &	requests
	)

Blocks until all communication operations associated with the CommRequest objects have completed.

template<typename Ordinal >

void waitAll	(	const Comm< Ordinal > &	comm,
		const ArrayView< RCP< CommRequest< Ordinal > > > &	requests,
		const ArrayView< RCP< CommStatus< Ordinal > > > &	statuses
	)

This function will block until all the communication operations complete. You are responsible for ordering messages in a way that avoids deadlock. An erroneous ordering of messages may cause this function to wait forever.

Precondition: requests.size() == statuses.size(); For i in 0, 1, ..., requests.size() - 1, requests[i] is either null or it was the return value of a nonblocking communication request.

Postcondition: For i in 0, 1, ..., requests.size() - 1, requests[i] is null. If requests[i] were nonnull on input, then the corresponding nonblocking communication operation completed successfully.

Parameters

comm	[in] The communicator on which the communication requests were made.
requests	[in/out] On input: the requests on which to wait. Null elements of the array are ignored. On output: all elements of the array are set to null.
statuses	[out] CommStatus instances representing the results of completing the requests. You may query each for information about its corresponding communication operation. Any element of the array may be null, for example if its corresponding CommRequest was null on input.

template<typename Ordinal >

RCP< CommStatus< Ordinal > > wait	(	const Comm< Ordinal > &	comm,
		const Ptr< RCP< CommRequest< Ordinal > > > &	request
	)

This function will block until the communication operation completes. You are responsible for ordering messages in a way that avoids deadlock. An erroneous ordering of messages may cause this function to wait forever.

Parameters

request [in/out] A nonnull pointer to an RCP. On input, the RCP is either null (in which case this function does nothing) or it points to a valid CommRequest representing an outstanding communication request. On output, this function sets *request to null, which indicates that the request completed successfully. (This function will not return unless the request completes.)

Returns: A CommStatus instance representing the result of completing the request. You may query it for information about the completed communication operation. This may be null, for example if *request was null on input.

Precondition: !is_null(request) (that is, the Ptr is not null).

Postcondition: is_null(*request) (that is, the RCP is null).

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

Public Member Functions

Related Functions

Additional Inherited Members

Detailed Description

template<class OrdinalType> class Teuchos::Comm< OrdinalType >

What is Comm?

Treat <tt>RCP<const Comm<int> ></tt> like an opaque handle

How do I make a Comm?

How do I use Comm?

Former documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

template<class OrdinalType>
class Teuchos::Comm< OrdinalType >