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// Copyright (C) 2005, 2006 Douglas Gregor <doug.gregor -at- gmail.com>.
// Copyright (C) 2016 K. Noel Belcourt <kbelco -at- sandia.gov>.
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
/** @file communicator.hpp
*
* This header defines the @c communicator class, which is the basis
* of all communication within Boost.MPI, and provides point-to-point
* communication operations.
*/
#ifndef BOOST_MPI_COMMUNICATOR_HPP
#define BOOST_MPI_COMMUNICATOR_HPP
#include <boost/assert.hpp>
#include <boost/mpi/config.hpp>
#include <boost/mpi/exception.hpp>
#include <boost/optional.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/mpi/datatype.hpp>
#include <boost/mpi/nonblocking.hpp>
#include <boost/static_assert.hpp>
#include <utility>
#include <iterator>
#include <stdexcept> // for std::range_error
#include <vector>
// For (de-)serializing sends and receives
#include <boost/mpi/packed_oarchive.hpp>
#include <boost/mpi/packed_iarchive.hpp>
// For (de-)serializing skeletons and content
#include <boost/mpi/skeleton_and_content_fwd.hpp>
#include <boost/mpi/detail/point_to_point.hpp>
#include <boost/mpi/status.hpp>
#include <boost/mpi/request.hpp>
#ifdef BOOST_MSVC
# pragma warning(push)
# pragma warning(disable : 4800) // forcing to bool 'true' or 'false'
#endif
namespace boost { namespace mpi {
/**
* @brief A constant representing "any process."
*
* This constant may be used for the @c source parameter of @c receive
* operations to indicate that a message may be received from any
* source.
*/
const int any_source = MPI_ANY_SOURCE;
/**
* @brief A constant representing "any tag."
*
* This constant may be used for the @c tag parameter of @c receive
* operations to indicate that a @c send with any tag will be matched
* by the receive.
*/
const int any_tag = MPI_ANY_TAG;
/**
* @brief Enumeration used to describe how to adopt a C @c MPI_Comm into
* a Boost.MPI communicator.
*
* The values for this enumeration determine how a Boost.MPI
* communicator will behave when constructed with an MPI
* communicator. The options are:
*
* - @c comm_duplicate: Duplicate the MPI_Comm communicator to
* create a new communicator (e.g., with MPI_Comm_dup). This new
* MPI_Comm communicator will be automatically freed when the
* Boost.MPI communicator (and all copies of it) is destroyed.
*
* - @c comm_take_ownership: Take ownership of the communicator. It
* will be freed automatically when all of the Boost.MPI
* communicators go out of scope. This option must not be used with
* MPI_COMM_WORLD.
*
* - @c comm_attach: The Boost.MPI communicator will reference the
* existing MPI communicator but will not free it when the Boost.MPI
* communicator goes out of scope. This option should only be used
* when the communicator is managed by the user or MPI library
* (e.g., MPI_COMM_WORLD).
*/
enum comm_create_kind { comm_duplicate, comm_take_ownership, comm_attach };
/**
* INTERNAL ONLY
*
* Forward declaration of @c group needed for the @c group
* constructor and accessor.
*/
class group;
/**
* INTERNAL ONLY
*
* Forward declaration of @c intercommunicator needed for the "cast"
* from a communicator to an intercommunicator.
*/
class intercommunicator;
/**
* INTERNAL ONLY
*
* Forward declaration of @c graph_communicator needed for the "cast"
* from a communicator to a graph communicator.
*/
class graph_communicator;
/**
* INTERNAL ONLY
*
* Forward declaration of @c cartesian_communicator needed for the "cast"
* from a communicator to a cartesian communicator.
*/
class cartesian_communicator;
/**
* @brief A communicator that permits communication and
* synchronization among a set of processes.
*
* The @c communicator class abstracts a set of communicating
* processes in MPI. All of the processes that belong to a certain
* communicator can determine the size of the communicator, their rank
* within the communicator, and communicate with any other processes
* in the communicator.
*/
class BOOST_MPI_DECL communicator
{
public:
/**
* Build a new Boost.MPI communicator for @c MPI_COMM_WORLD.
*
* Constructs a Boost.MPI communicator that attaches to @c
* MPI_COMM_WORLD. This is the equivalent of constructing with
* @c (MPI_COMM_WORLD, comm_attach).
*/
communicator();
/**
* Build a new Boost.MPI communicator based on the MPI communicator
* @p comm.
*
* @p comm may be any valid MPI communicator. If @p comm is
* MPI_COMM_NULL, an empty communicator (that cannot be used for
* communication) is created and the @p kind parameter is
* ignored. Otherwise, the @p kind parameters determines how the
* Boost.MPI communicator will be related to @p comm:
*
* - If @p kind is @c comm_duplicate, duplicate @c comm to create
* a new communicator. This new communicator will be freed when
* the Boost.MPI communicator (and all copies of it) is destroyed.
* This option is only permitted if @p comm is a valid MPI
* intracommunicator or if the underlying MPI implementation
* supports MPI 2.0 (which supports duplication of
* intercommunicators).
*
* - If @p kind is @c comm_take_ownership, take ownership of @c
* comm. It will be freed automatically when all of the Boost.MPI
* communicators go out of scope. This option must not be used
* when @c comm is MPI_COMM_WORLD.
*
* - If @p kind is @c comm_attach, this Boost.MPI communicator
* will reference the existing MPI communicator @p comm but will
* not free @p comm when the Boost.MPI communicator goes out of
* scope. This option should only be used when the communicator is
* managed by the user or MPI library (e.g., MPI_COMM_WORLD).
*/
communicator(const MPI_Comm& comm, comm_create_kind kind);
/**
* Build a new Boost.MPI communicator based on a subgroup of another
* MPI communicator.
*
* This routine will construct a new communicator containing all of
* the processes from communicator @c comm that are listed within
* the group @c subgroup. Equivalent to @c MPI_Comm_create.
*
* @param comm An MPI communicator.
*
* @param subgroup A subgroup of the MPI communicator, @p comm, for
* which we will construct a new communicator.
*/
communicator(const communicator& comm, const boost::mpi::group& subgroup);
/**
* @brief Determine the rank of the executing process in a
* communicator.
*
* This routine is equivalent to @c MPI_Comm_rank.
*
* @returns The rank of the process in the communicator, which
* will be a value in [0, size())
*/
int rank() const;
/**
* @brief Determine the number of processes in a communicator.
*
* This routine is equivalent to @c MPI_Comm_size.
*
* @returns The number of processes in the communicator.
*/
int size() const;
/**
* This routine constructs a new group whose members are the
* processes within this communicator. Equivalent to
* calling @c MPI_Comm_group.
*/
boost::mpi::group group() const;
// ----------------------------------------------------------------
// Point-to-point communication
// ----------------------------------------------------------------
/**
* @brief Send data to another process.
*
* This routine executes a potentially blocking send with tag @p tag
* to the process with rank @p dest. It can be received by the
* destination process with a matching @c recv call.
*
* The given @p value must be suitable for transmission over
* MPI. There are several classes of types that meet these
* requirements:
*
* - Types with mappings to MPI data types: If @c
* is_mpi_datatype<T> is convertible to @c mpl::true_, then @p
* value will be transmitted using the MPI data type
* @c get_mpi_datatype<T>(). All primitive C++ data types that have
* MPI equivalents, e.g., @c int, @c float, @c char, @c double,
* etc., have built-in mappings to MPI data types. You may turn a
* Serializable type with fixed structure into an MPI data type by
* specializing @c is_mpi_datatype for your type.
*
* - Serializable types: Any type that provides the @c serialize()
* functionality required by the Boost.Serialization library can be
* transmitted and received.
*
* - Packed archives and skeletons: Data that has been packed into
* an @c mpi::packed_oarchive or the skeletons of data that have
* been backed into an @c mpi::packed_skeleton_oarchive can be
* transmitted, but will be received as @c mpi::packed_iarchive and
* @c mpi::packed_skeleton_iarchive, respectively, to allow the
* values (or skeletons) to be extracted by the destination process.
*
* - Content: Content associated with a previously-transmitted
* skeleton can be transmitted by @c send and received by @c
* recv. The receiving process may only receive content into the
* content of a value that has been constructed with the matching
* skeleton.
*
* For types that have mappings to an MPI data type (including the
* concent of a type), an invocation of this routine will result in
* a single MPI_Send call. For variable-length data, e.g.,
* serialized types and packed archives, two messages will be sent
* via MPI_Send: one containing the length of the data and the
* second containing the data itself.
*
* Std::vectors of MPI data type
* are considered variable size, e.g. their number of elements is
* unknown and must be transmited (although the serialization process
* is skipped). You can use the array specialized versions of
* communication methods is both sender and receiver know the vector
* size.
*
* Note that the transmission mode for variable-length data is an
* implementation detail that is subject to change.
*
* @param dest The rank of the remote process to which the data
* will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
* @param value The value that will be transmitted to the
* receiver. The type @c T of this value must meet the aforementioned
* criteria for transmission.
*/
template<typename T>
void send(int dest, int tag, const T& value) const;
template<typename T, typename A>
void send(int dest, int tag, const std::vector<T,A>& value) const;
/**
* @brief Send the skeleton of an object.
*
* This routine executes a potentially blocking send with tag @p
* tag to the process with rank @p dest. It can be received by the
* destination process with a matching @c recv call. This variation
* on @c send will be used when a send of a skeleton is explicitly
* requested via code such as:
*
* @code
* comm.send(dest, tag, skeleton(object));
* @endcode
*
* The semantics of this routine are equivalent to that of sending
* a @c packed_skeleton_oarchive storing the skeleton of the @c
* object.
*
* @param dest The rank of the remote process to which the skeleton
* will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
* @param proxy The @c skeleton_proxy containing a reference to the
* object whose skeleton will be transmitted.
*
*/
template<typename T>
void send(int dest, int tag, const skeleton_proxy<T>& proxy) const;
/**
* @brief Send an array of values to another process.
*
* This routine executes a potentially blocking send of an array of
* data with tag @p tag to the process with rank @p dest. It can be
* received by the destination process with a matching array @c
* recv call.
*
* If @c T is an MPI datatype, an invocation of this routine will
* be mapped to a single call to MPI_Send, using the datatype @c
* get_mpi_datatype<T>().
*
* @param dest The process rank of the remote process to which
* the data will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
* @param values The array of values that will be transmitted to the
* receiver. The type @c T of these values must be mapped to an MPI
* data type.
*
* @param n The number of values stored in the array. The destination
* process must call receive with at least this many elements to
* correctly receive the message.
*/
template<typename T>
void send(int dest, int tag, const T* values, int n) const;
/**
* @brief Send a message to another process without any data.
*
* This routine executes a potentially blocking send of a message
* to another process. The message contains no extra data, and can
* therefore only be received by a matching call to @c recv().
*
* @param dest The process rank of the remote process to which
* the message will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
*/
void send(int dest, int tag) const;
/**
* @brief Receive data from a remote process.
*
* This routine blocks until it receives a message from the process @p
* source with the given @p tag. The type @c T of the @p value must be
* suitable for transmission over MPI, which includes serializable
* types, types that can be mapped to MPI data types (including most
* built-in C++ types), packed MPI archives, skeletons, and content
* associated with skeletons; see the documentation of @c send for a
* complete description.
*
* @param source The process that will be sending data. This will
* either be a process rank within the communicator or the
* constant @c any_source, indicating that we can receive the
* message from any process.
*
* @param tag The tag that matches a particular kind of message sent
* by the source process. This may be any tag value permitted by @c
* send. Alternatively, the argument may be the constant @c any_tag,
* indicating that this receive matches a message with any tag.
*
* @param value Will contain the value of the message after a
* successful receive. The type of this value must match the value
* transmitted by the sender, unless the sender transmitted a packed
* archive or skeleton: in these cases, the sender transmits a @c
* packed_oarchive or @c packed_skeleton_oarchive and the
* destination receives a @c packed_iarchive or @c
* packed_skeleton_iarchive, respectively.
*
* @returns Information about the received message.
*/
template<typename T>
status recv(int source, int tag, T& value) const;
template<typename T, typename A>
status recv(int source, int tag, std::vector<T,A>& value) const;
/**
* @brief Receive a skeleton from a remote process.
*
* This routine blocks until it receives a message from the process @p
* source with the given @p tag containing a skeleton.
*
* @param source The process that will be sending data. This will
* either be a process rank within the communicator or the constant
* @c any_source, indicating that we can receive the message from
* any process.
*
* @param tag The tag that matches a particular kind of message
* sent by the source process. This may be any tag value permitted
* by @c send. Alternatively, the argument may be the constant @c
* any_tag, indicating that this receive matches a message with any
* tag.
*
* @param proxy The @c skeleton_proxy containing a reference to the
* object that will be reshaped to match the received skeleton.
*
* @returns Information about the received message.
*/
template<typename T>
status recv(int source, int tag, const skeleton_proxy<T>& proxy) const;
/**
* @brief Receive a skeleton from a remote process.
*
* This routine blocks until it receives a message from the process @p
* source with the given @p tag containing a skeleton.
*
* @param source The process that will be sending data. This will
* either be a process rank within the communicator or the constant
* @c any_source, indicating that we can receive the message from
* any process.
*
* @param tag The tag that matches a particular kind of message
* sent by the source process. This may be any tag value permitted
* by @c send. Alternatively, the argument may be the constant @c
* any_tag, indicating that this receive matches a message with any
* tag.
*
* @param proxy The @c skeleton_proxy containing a reference to the
* object that will be reshaped to match the received skeleton.
*
* @returns Information about the received message.
*/
template<typename T>
status recv(int source, int tag, skeleton_proxy<T>& proxy) const;
/**
* @brief Receive an array of values from a remote process.
*
* This routine blocks until it receives an array of values from the
* process @p source with the given @p tag. If the type @c T is
*
* @param source The process that will be sending data. This will
* either be a process rank within the communicator or the
* constant @c any_source, indicating that we can receive the
* message from any process.
*
* @param tag The tag that matches a particular kind of message sent
* by the source process. This may be any tag value permitted by @c
* send. Alternatively, the argument may be the constant @c any_tag,
* indicating that this receive matches a message with any tag.
*
* @param values Will contain the values in the message after a
* successful receive. The type of these elements must match the
* type of the elements transmitted by the sender.
*
* @param n The number of values that can be stored into the @p
* values array. This shall not be smaller than the number of
* elements transmitted by the sender.
*
* @throws std::range_error if the message to be received contains
* more than @p n values.
*
* @returns Information about the received message.
*/
template<typename T>
status recv(int source, int tag, T* values, int n) const;
/**
* @brief Receive a message from a remote process without any data.
*
* This routine blocks until it receives a message from the process
* @p source with the given @p tag.
*
* @param source The process that will be sending the message. This
* will either be a process rank within the communicator or the
* constant @c any_source, indicating that we can receive the
* message from any process.
*
* @param tag The tag that matches a particular kind of message
* sent by the source process. This may be any tag value permitted
* by @c send. Alternatively, the argument may be the constant @c
* any_tag, indicating that this receive matches a message with any
* tag.
*
* @returns Information about the received message.
*/
status recv(int source, int tag) const;
/** @brief Send a message to remote process and receive another message
* from another process.
*/
template<typename T>
status sendrecv(int dest, int stag, const T& sval, int src, int rtag, T& rval) const;
/**
* @brief Send a message to a remote process without blocking.
*
* The @c isend method is functionality identical to the @c send
* method and transmits data in the same way, except that @c isend
* will not block while waiting for the data to be
* transmitted. Instead, a request object will be immediately
* returned, allowing one to query the status of the communication
* or wait until it has completed.
*
* @param dest The rank of the remote process to which the data
* will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
* @param value The value that will be transmitted to the
* receiver. The type @c T of this value must meet the aforementioned
* criteria for transmission. If modified before transmited, the
* modification may or may not be transmited.
*
* @returns a @c request object that describes this communication.
*/
template<typename T>
request isend(int dest, int tag, const T& value) const;
/**
* @brief Send the skeleton of an object without blocking.
*
* This routine is functionally identical to the @c send method for
* @c skeleton_proxy objects except that @c isend will not block
* while waiting for the data to be transmitted. Instead, a request
* object will be immediately returned, allowing one to query the
* status of the communication or wait until it has completed.
*
* The semantics of this routine are equivalent to a non-blocking
* send of a @c packed_skeleton_oarchive storing the skeleton of
* the @c object.
*
* @param dest The rank of the remote process to which the skeleton
* will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
* @param proxy The @c skeleton_proxy containing a reference to the
* object whose skeleton will be transmitted.
*
* @returns a @c request object that describes this communication.
*/
template<typename T>
request isend(int dest, int tag, const skeleton_proxy<T>& proxy) const;
/**
* @brief Send an array of values to another process without
* blocking.
*
* This routine is functionally identical to the @c send method for
* arrays except that @c isend will not block while waiting for the
* data to be transmitted. Instead, a request object will be
* immediately returned, allowing one to query the status of the
* communication or wait until it has completed.
*
* @param dest The process rank of the remote process to which
* the data will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
* @param values The array of values that will be transmitted to the
* receiver. The type @c T of these values must be mapped to an MPI
* data type.
*
* @param n The number of values stored in the array. The destination
* process must call receive with at least this many elements to
* correctly receive the message.
*
* @returns a @c request object that describes this communication.
*/
template<typename T>
request isend(int dest, int tag, const T* values, int n) const;
template<typename T, class A>
request isend(int dest, int tag, const std::vector<T,A>& values) const;
/**
* @brief Send a message to another process without any data
* without blocking.
*
* This routine is functionally identical to the @c send method for
* sends with no data, except that @c isend will not block while
* waiting for the message to be transmitted. Instead, a request
* object will be immediately returned, allowing one to query the
* status of the communication or wait until it has completed.
*
* @param dest The process rank of the remote process to which
* the message will be sent.
*
* @param tag The tag that will be associated with this message. Tags
* may be any integer between zero and an implementation-defined
* upper limit. This limit is accessible via @c environment::max_tag().
*
*
* @returns a @c request object that describes this communication.
*/
request isend(int dest, int tag) const;
/**
* @brief Prepare to receive a message from a remote process.
*
* The @c irecv method is functionally identical to the @c recv
* method and receive data in the same way, except that @c irecv
* will not block while waiting for data to be
* transmitted. Instead, it immediately returns a request object
* that allows one to query the status of the receive or wait until
* it has completed.
*
* @param source The process that will be sending data. This will
* either be a process rank within the communicator or the
* constant @c any_source, indicating that we can receive the
* message from any process.
*
* @param tag The tag that matches a particular kind of message sent
* by the source process. This may be any tag value permitted by @c
* send. Alternatively, the argument may be the constant @c any_tag,
* indicating that this receive matches a message with any tag.
*
* @param value Will contain the value of the message after a
* successful receive. The type of this value must match the value
* transmitted by the sender, unless the sender transmitted a packed
* archive or skeleton: in these cases, the sender transmits a @c
* packed_oarchive or @c packed_skeleton_oarchive and the
* destination receives a @c packed_iarchive or @c
* packed_skeleton_iarchive, respectively.
*
* @returns a @c request object that describes this communication.
*/
template<typename T>
request irecv(int source, int tag, T& value) const;
/**
* @brief Initiate receipt of an array of values from a remote process.
*
* This routine initiates a receive operation for an array of values
* transmitted by process @p source with the given @p tag.
*
* @param source The process that will be sending data. This will
* either be a process rank within the communicator or the
* constant @c any_source, indicating that we can receive the
* message from any process.
*
* @param tag The tag that matches a particular kind of message sent
* by the source process. This may be any tag value permitted by @c
* send. Alternatively, the argument may be the constant @c any_tag,
* indicating that this receive matches a message with any tag.
*
* @param values Will contain the values in the message after a
* successful receive. The type of these elements must match the
* type of the elements transmitted by the sender.
*
* @param n The number of values that can be stored into the @p
* values array. This shall not be smaller than the number of
* elements transmitted by the sender.
*
* @returns a @c request object that describes this communication.
*/
template<typename T>
request irecv(int source, int tag, T* values, int n) const;
template<typename T, typename A>
request irecv(int source, int tag, std::vector<T,A>& values) const;
/**
* @brief Initiate receipt of a message from a remote process that
* carries no data.
*
* This routine initiates a receive operation for a message from
* process @p source with the given @p tag that carries no data.
*
* @param source The process that will be sending the message. This
* will either be a process rank within the communicator or the
* constant @c any_source, indicating that we can receive the
* message from any process.
*
* @param tag The tag that matches a particular kind of message
* sent by the source process. This may be any tag value permitted
* by @c send. Alternatively, the argument may be the constant @c
* any_tag, indicating that this receive matches a message with any
* tag.
*
* @returns a @c request object that describes this communication.
*/
request irecv(int source, int tag) const;
/**
* @brief Waits until a message is available to be received.
*
* This operation waits until a message matching (@p source, @p tag)
* is available to be received. It then returns information about
* that message. The functionality is equivalent to @c MPI_Probe. To
* check if a message is available without blocking, use @c iprobe.
*
* @param source Determine if there is a message available from
* this rank. If @c any_source, then the message returned may come
* from any source.
*
* @param tag Determine if there is a message available with the
* given tag. If @c any_tag, then the message returned may have any
* tag.
*
* @returns Returns information about the first message that
* matches the given criteria.
*/
status probe(int source = any_source, int tag = any_tag) const;
/**
* @brief Determine if a message is available to be received.
*
* This operation determines if a message matching (@p source, @p
* tag) is available to be received. If so, it returns information
* about that message; otherwise, it returns immediately with an
* empty optional. The functionality is equivalent to @c
* MPI_Iprobe. To wait until a message is available, use @c wait.
*
* @param source Determine if there is a message available from
* this rank. If @c any_source, then the message returned may come
* from any source.
*
* @param tag Determine if there is a message available with the
* given tag. If @c any_tag, then the message returned may have any
* tag.
*
* @returns If a matching message is available, returns
* information about that message. Otherwise, returns an empty
* @c boost::optional.
*/
optional<status>
iprobe(int source = any_source, int tag = any_tag) const;
#ifdef barrier
// Linux defines a function-like macro named "barrier". So, we need
// to avoid expanding the macro when we define our barrier()
// function. However, some C++ parsers (Doxygen, for instance) can't
// handle this syntax, so we only use it when necessary.
void (barrier)() const;
#else
/**
* @brief Wait for all processes within a communicator to reach the
* barrier.
*
* This routine is a collective operation that blocks each process
* until all processes have entered it, then releases all of the
* processes "simultaneously". It is equivalent to @c MPI_Barrier.
*/
void barrier() const;
#endif
/** @brief Determine if this communicator is valid for
* communication.
*
* Evaluates @c true in a boolean context if this communicator is
* valid for communication, i.e., does not represent
* MPI_COMM_NULL. Otherwise, evaluates @c false.
*/
operator bool() const { return (bool)comm_ptr; }
/**
* @brief Access the MPI communicator associated with a Boost.MPI
* communicator.
*
* This routine permits the implicit conversion from a Boost.MPI
* communicator to an MPI communicator.
*
* @returns The associated MPI communicator.
*/
operator MPI_Comm() const;
/**
* Split the communicator into multiple, disjoint communicators
* each of which is based on a particular color. This is a
* collective operation that returns a new communicator that is a
* subgroup of @p this.
*
* @param color The color of this process. All processes with the
* same @p color value will be placed into the same group.
*
* @param key A key value that will be used to determine the
* ordering of processes with the same color in the resulting
* communicator. If omitted, the rank of the processes in @p this
* will determine the ordering of processes in the resulting
* group.
*
* @returns A new communicator containing all of the processes in
* @p this that have the same @p color.
*/
communicator split(int color, int key) const;
communicator split(int color) const;
/**
* Determine if the communicator is in fact an intercommunicator
* and, if so, return that intercommunicator.
*
* @returns an @c optional containing the intercommunicator, if this
* communicator is in fact an intercommunicator. Otherwise, returns
* an empty @c optional.
*/
optional<intercommunicator> as_intercommunicator() const;
/**
* Determine if the communicator has a graph topology and, if so,
* return that @c graph_communicator. Even though the communicators
* have different types, they refer to the same underlying
* communication space and can be used interchangeably for
* communication.
*
* @returns an @c optional containing the graph communicator, if this
* communicator does in fact have a graph topology. Otherwise, returns
* an empty @c optional.
*/
optional<graph_communicator> as_graph_communicator() const;
/**
* Determines whether this communicator has a Graph topology.
*/
bool has_graph_topology() const;
/**
* Determine if the communicator has a cartesian topology and, if so,
* return that @c cartesian_communicator. Even though the communicators
* have different types, they refer to the same underlying
* communication space and can be used interchangeably for
* communication.
*
* @returns an @c optional containing the cartesian communicator, if this
* communicator does in fact have a cartesian topology. Otherwise, returns
* an empty @c optional.
*/
optional<cartesian_communicator> as_cartesian_communicator() const;
/**
* Determines whether this communicator has a Cartesian topology.
*/
bool has_cartesian_topology() const;
/** Abort all tasks in the group of this communicator.
*
* Makes a "best attempt" to abort all of the tasks in the group of
* this communicator. Depending on the underlying MPI
* implementation, this may either abort the entire program (and
* possibly return @p errcode to the environment) or only abort
* some processes, allowing the others to continue. Consult the
* documentation for your MPI implementation. This is equivalent to
* a call to @c MPI_Abort
*
* @param errcode The error code to return from aborted processes.
* @returns Will not return.
*/
void abort(int errcode) const;
protected:
/**
* INTERNAL ONLY
*
* Implementation of sendrecv for mpi type.
*/
template<typename T>
status sendrecv_impl(int dest, int stag, const T& sval, int src, int rtag, T& rval,
mpl::true_) const;
/**
* INTERNAL ONLY
*
* Implementation of sendrecv for complex types, which must be passed as archives.
*/
template<typename T>
status sendrecv_impl(int dest, int stag, const T& sval, int src, int rtag, T& rval,
mpl::false_) const;
/**
* INTERNAL ONLY
*
* Function object that frees an MPI communicator and deletes the
* memory associated with it. Intended to be used as a deleter with
* shared_ptr.
*/
struct comm_free
{
void operator()(MPI_Comm* comm) const
{
BOOST_ASSERT( comm != 0 );
BOOST_ASSERT(*comm != MPI_COMM_NULL);
int finalized;
BOOST_MPI_CHECK_RESULT(MPI_Finalized, (&finalized));
if (!finalized)
BOOST_MPI_CHECK_RESULT(MPI_Comm_free, (comm));
delete comm;
}
};
/**
* INTERNAL ONLY
*
* We're sending a type that has an associated MPI datatype, so we
* map directly to that datatype.
*/
template<typename T>
void send_impl(int dest, int tag, const T& value, mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're sending a type that does not have an associated MPI
* datatype, so it must be serialized then sent as MPI_PACKED data,
* to be deserialized on the receiver side.
*/
template<typename T>
void send_impl(int dest, int tag, const T& value, mpl::false_) const;
/**
* INTERNAL ONLY
*
* We're sending an array of a type that has an associated MPI
* datatype, so we map directly to that datatype.
*/
template<typename T>
void
array_send_impl(int dest, int tag, const T* values, int n, mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're sending an array of a type that does not have an associated
* MPI datatype, so it must be serialized then sent as MPI_PACKED
* data, to be deserialized on the receiver side.
*/
template<typename T>
void
array_send_impl(int dest, int tag, const T* values, int n,
mpl::false_) const;
/**
* INTERNAL ONLY
*
* We're sending a type that has an associated MPI datatype, so we
* map directly to that datatype.
*/
template<typename T>
request isend_impl(int dest, int tag, const T& value, mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're sending a type that does not have an associated MPI
* datatype, so it must be serialized then sent as MPI_PACKED data,
* to be deserialized on the receiver side.
*/
template<typename T>
request isend_impl(int dest, int tag, const T& value, mpl::false_) const;
/**
* INTERNAL ONLY
*
* We're sending an array of a type that has an associated MPI
* datatype, so we map directly to that datatype.
*/
template<typename T>
request
array_isend_impl(int dest, int tag, const T* values, int n,
mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're sending an array of a type that does not have an associated
* MPI datatype, so it must be serialized then sent as MPI_PACKED
* data, to be deserialized on the receiver side.
*/
template<typename T>
request
array_isend_impl(int dest, int tag, const T* values, int n,
mpl::false_) const;
/**
* INTERNAL ONLY
*
* We're receiving a type that has an associated MPI datatype, so we
* map directly to that datatype.
*/
template<typename T>
status recv_impl(int source, int tag, T& value, mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're receiving a type that does not have an associated MPI
* datatype, so it must have been serialized then sent as
* MPI_PACKED. We'll receive it and then deserialize.
*/
template<typename T>
status recv_impl(int source, int tag, T& value, mpl::false_) const;
/**
* INTERNAL ONLY
*
* We're receiving an array of a type that has an associated MPI
* datatype, so we map directly to that datatype.
*/
template<typename T>
status
array_recv_impl(int source, int tag, T* values, int n, mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're receiving a type that does not have an associated MPI
* datatype, so it must have been serialized then sent as
* MPI_PACKED. We'll receive it and then deserialize.
*/
template<typename T>
status
array_recv_impl(int source, int tag, T* values, int n, mpl::false_) const;
/**
* INTERNAL ONLY
*
* We're receiving a type that has an associated MPI datatype, so we
* map directly to that datatype.
*/
template<typename T>
request irecv_impl(int source, int tag, T& value, mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're receiving a type that does not have an associated MPI
* datatype, so it must have been serialized then sent as
* MPI_PACKED. We'll receive it and then deserialize.
*/
template<typename T>
request irecv_impl(int source, int tag, T& value, mpl::false_) const;
/**
* INTERNAL ONLY
*
* We're receiving a type that has an associated MPI datatype, so we
* map directly to that datatype.
*/
template<typename T>
request
array_irecv_impl(int source, int tag, T* values, int n, mpl::true_) const;
/**
* INTERNAL ONLY
*
* We're receiving a type that does not have an associated MPI
* datatype, so it must have been serialized then sent as
* MPI_PACKED. We'll receive it and then deserialize.
*/
template<typename T>
request
array_irecv_impl(int source, int tag, T* values, int n, mpl::false_) const;
// We're sending/receivig a vector with associated MPI datatype.
// We need to send/recv the size and then the data and make sure
// blocking and non blocking method agrees on the format.
template<typename T, typename A>
request irecv_vector(int source, int tag, std::vector<T,A>& values,
mpl::true_) const;
template<typename T, class A>
request isend_vector(int dest, int tag, const std::vector<T,A>& values,
mpl::true_) const;
template<typename T, typename A>
void send_vector(int dest, int tag, const std::vector<T,A>& value,
mpl::true_) const;
template<typename T, typename A>
status recv_vector(int source, int tag, std::vector<T,A>& value,
mpl::true_) const;
// We're sending/receivig a vector with no associated MPI datatype.
// We need to send/recv it as an archive and make sure
// blocking and non blocking method agrees on the format.
template<typename T, typename A>
request irecv_vector(int source, int tag, std::vector<T,A>& values,
mpl::false_) const;
template<typename T, class A>
request isend_vector(int dest, int tag, const std::vector<T,A>& values,
mpl::false_) const;
template<typename T, typename A>
void send_vector(int dest, int tag, const std::vector<T,A>& value,
mpl::false_) const;
template<typename T, typename A>
status recv_vector(int source, int tag, std::vector<T,A>& value,
mpl::false_) const;
protected:
shared_ptr<MPI_Comm> comm_ptr;
};
/**
* @brief Determines whether two communicators are identical.
*
* Equivalent to calling @c MPI_Comm_compare and checking whether the
* result is @c MPI_IDENT.
*
* @returns True when the two communicators refer to the same
* underlying MPI communicator.
*/
BOOST_MPI_DECL bool operator==(const communicator& comm1, const communicator& comm2);
/**
* @brief Determines whether two communicators are different.
*
* @returns @c !(comm1 == comm2)
*/
inline bool operator!=(const communicator& comm1, const communicator& comm2)
{
return !(comm1 == comm2);
}
}} // boost::mpi
/************************************************************************
* Implementation details *
************************************************************************/
#include <boost/mpi/detail/request_handlers.hpp>
namespace boost { namespace mpi {
/**
* INTERNAL ONLY (using the same 'end' name might be considerd unfortunate
*/
template<>
BOOST_MPI_DECL void
communicator::send<packed_oarchive>(int dest, int tag,
const packed_oarchive& ar) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL void
communicator::send<packed_skeleton_oarchive>
(int dest, int tag, const packed_skeleton_oarchive& ar) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL void
communicator::send<content>(int dest, int tag, const content& c) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL status
communicator::recv<packed_iarchive>(int source, int tag,
packed_iarchive& ar) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL status
communicator::recv<packed_skeleton_iarchive>
(int source, int tag, packed_skeleton_iarchive& ar) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL status
communicator::recv<const content>(int source, int tag,
const content& c) const;
/**
* INTERNAL ONLY
*/
template<>
inline status
communicator::recv<content>(int source, int tag,
content& c) const
{
return recv<const content>(source,tag,c);
}
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL request
communicator::isend<packed_oarchive>(int dest, int tag,
const packed_oarchive& ar) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL request
communicator::isend<packed_skeleton_oarchive>
(int dest, int tag, const packed_skeleton_oarchive& ar) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL request
communicator::isend<content>(int dest, int tag, const content& c) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL request
communicator::irecv<packed_skeleton_iarchive>
(int source, int tag, packed_skeleton_iarchive& ar) const;
/**
* INTERNAL ONLY
*/
template<>
BOOST_MPI_DECL request
communicator::irecv<const content>(int source, int tag,
const content& c) const;
/**
* INTERNAL ONLY
*/
template<>
inline request
communicator::irecv<content>(int source, int tag,
content& c) const
{
return irecv<const content>(source, tag, c);
}
// We're sending a type that has an associated MPI datatype, so we
// map directly to that datatype.
template<typename T>
void
communicator::send_impl(int dest, int tag, const T& value, mpl::true_) const
{
// received by recv or trivial handler.
BOOST_MPI_CHECK_RESULT(MPI_Send,
(const_cast<T*>(&value), 1, get_mpi_datatype<T>(value),
dest, tag, MPI_Comm(*this)));
}
// We're sending a type that does not have an associated MPI
// datatype, so it must be serialized then sent as MPI_PACKED data,
// to be deserialized on the receiver side.
template<typename T>
void
communicator::send_impl(int dest, int tag, const T& value, mpl::false_) const
{
packed_oarchive oa(*this);
oa << value;
send(dest, tag, oa);
}
// Single-element receive may either send the element directly or
// serialize it via a buffer.
template<typename T>
void communicator::send(int dest, int tag, const T& value) const
{
this->send_impl(dest, tag, value, is_mpi_datatype<T>());
}
// We're sending an array of a type that has an associated MPI
// datatype, so we map directly to that datatype.
template<typename T>
void
communicator::array_send_impl(int dest, int tag, const T* values, int n,
mpl::true_) const
{
BOOST_MPI_CHECK_RESULT(MPI_Send,
(const_cast<T*>(values), n,
get_mpi_datatype<T>(*values),
dest, tag, MPI_Comm(*this)));
}
// We're sending an array of a type that does not have an associated
// MPI datatype, so it must be serialized then sent as MPI_PACKED
// data, to be deserialized on the receiver side.
template<typename T>
void
communicator::array_send_impl(int dest, int tag, const T* values, int n,
mpl::false_) const
{
packed_oarchive oa(*this);
T const* v = values;
while (v < values+n) {
oa << *v++;
}
send(dest, tag, oa);
}
template<typename T, typename A>
void communicator::send_vector(int dest, int tag,
const std::vector<T,A>& values, mpl::true_ primitive) const
{
#if defined(BOOST_MPI_USE_IMPROBE)
array_send_impl(dest, tag, values.data(), values.size(), primitive);
#else
{
// non blocking recv by legacy_dynamic_primitive_array_handler
// blocking recv by recv_vector(source,tag,value,primitive)
// send the vector size
typename std::vector<T,A>::size_type size = values.size();
send(dest, tag, size);
// send the data
this->array_send_impl(dest, tag, values.data(), size, primitive);
}
#endif
}
template<typename T, typename A>
void communicator::send_vector(int dest, int tag,
const std::vector<T,A>& value, mpl::false_ primitive) const
{
this->send_impl(dest, tag, value, primitive);
}
template<typename T, typename A>
void communicator::send(int dest, int tag, const std::vector<T,A>& value) const
{
send_vector(dest, tag, value, is_mpi_datatype<T>());
}
// Array send must send the elements directly
template<typename T>
void communicator::send(int dest, int tag, const T* values, int n) const
{
this->array_send_impl(dest, tag, values, n, is_mpi_datatype<T>());
}
// We're receiving a type that has an associated MPI datatype, so we
// map directly to that datatype.
template<typename T>
status communicator::recv_impl(int source, int tag, T& value, mpl::true_) const
{
status stat;
BOOST_MPI_CHECK_RESULT(MPI_Recv,
(const_cast<T*>(&value), 1,
get_mpi_datatype<T>(value),
source, tag, MPI_Comm(*this), &stat.m_status));
return stat;
}
template<typename T>
status
communicator::recv_impl(int source, int tag, T& value, mpl::false_) const
{
// Receive the message
packed_iarchive ia(*this);
status stat = recv(source, tag, ia);
// Deserialize the data in the message
ia >> value;
return stat;
}
// Single-element receive may either receive the element directly or
// deserialize it from a buffer.
template<typename T>
status communicator::recv(int source, int tag, T& value) const
{
return this->recv_impl(source, tag, value, is_mpi_datatype<T>());
}
template<typename T>
status
communicator::array_recv_impl(int source, int tag, T* values, int n,
mpl::true_) const
{
status stat;
BOOST_MPI_CHECK_RESULT(MPI_Recv,
(const_cast<T*>(values), n,
get_mpi_datatype<T>(*values),
source, tag, MPI_Comm(*this), &stat.m_status));
return stat;
}
template<typename T>
status
communicator::array_recv_impl(int source, int tag, T* values, int n,
mpl::false_) const
{
packed_iarchive ia(*this);
status stat = recv(source, tag, ia);
T* v = values;
while (v != values+n) {
ia >> *v++;
}
stat.m_count = n;
return stat;
}
template<typename T, typename A>
status communicator::recv_vector(int source, int tag,
std::vector<T,A>& values, mpl::true_ primitive) const
{
#if defined(BOOST_MPI_USE_IMPROBE)
{
MPI_Message msg;
status stat;
BOOST_MPI_CHECK_RESULT(MPI_Mprobe, (source,tag,*this,&msg,&stat.m_status));
int count;
BOOST_MPI_CHECK_RESULT(MPI_Get_count, (&stat.m_status,get_mpi_datatype<T>(),&count));
values.resize(count);
BOOST_MPI_CHECK_RESULT(MPI_Mrecv, (values.data(), count, get_mpi_datatype<T>(), &msg, &stat.m_status));
return stat;
}
#else
{
// receive the vector size
typename std::vector<T,A>::size_type size = 0;
recv(source, tag, size);
// size the vector
values.resize(size);
// receive the data
return this->array_recv_impl(source, tag, values.data(), size, primitive);
}
#endif
}
template<typename T, typename A>
status communicator::recv_vector(int source, int tag,
std::vector<T,A>& value, mpl::false_ false_type) const
{
return this->recv_impl(source, tag, value, false_type);
}
template<typename T, typename A>
status communicator::recv(int source, int tag, std::vector<T,A>& value) const
{
return recv_vector(source, tag, value, is_mpi_datatype<T>());
}
// Array receive must receive the elements directly into a buffer.
template<typename T>
status communicator::recv(int source, int tag, T* values, int n) const
{
return this->array_recv_impl(source, tag, values, n, is_mpi_datatype<T>());
}
template<typename T>
status communicator::sendrecv_impl(int dest, int stag, const T& sval, int src, int rtag, T& rval,
mpl::true_) const
{
status stat;
BOOST_MPI_CHECK_RESULT(MPI_Sendrecv,
(const_cast<T*>(&sval), 1,
get_mpi_datatype<T>(sval),
dest, stag,
&rval, 1,
get_mpi_datatype<T>(rval),
src, rtag,
MPI_Comm(*this), &stat.m_status));
return stat;
}
template<typename T>
status communicator::sendrecv_impl(int dest, int stag, const T& sval, int src, int rtag, T& rval,
mpl::false_) const
{
int const SEND = 0;
int const RECV = 1;
request srrequests[2];
srrequests[SEND] = this->isend_impl(dest, stag, sval, mpl::false_());
srrequests[RECV] = this->irecv_impl(src, rtag, rval, mpl::false_());
status srstatuses[2];
wait_all(srrequests, srrequests + 2, srstatuses);
return srstatuses[RECV];
}
template<typename T>
status communicator::sendrecv(int dest, int stag, const T& sval, int src, int rtag, T& rval) const
{
return this->sendrecv_impl(dest, stag, sval, src, rtag, rval, is_mpi_datatype<T>());
}
// We're sending a type that has an associated MPI datatype, so we
// map directly to that datatype.
template<typename T>
request
communicator::isend_impl(int dest, int tag, const T& value, mpl::true_) const
{
return request::make_trivial_send(*this, dest, tag, value);
}
// We're sending a type that does not have an associated MPI
// datatype, so it must be serialized then sent as MPI_PACKED data,
// to be deserialized on the receiver side.
template<typename T>
request
communicator::isend_impl(int dest, int tag, const T& value, mpl::false_) const
{
shared_ptr<packed_oarchive> archive(new packed_oarchive(*this));
*archive << value;
request result = isend(dest, tag, *archive);
result.preserve(archive);
return result;
}
// Single-element receive may either send the element directly or
// serialize it via a buffer.
template<typename T>
request communicator::isend(int dest, int tag, const T& value) const
{
return this->isend_impl(dest, tag, value, is_mpi_datatype<T>());
}
template<typename T, class A>
request communicator::isend(int dest, int tag, const std::vector<T,A>& values) const
{
return this->isend_vector(dest, tag, values, is_mpi_datatype<T>());
}
template<typename T, class A>
request
communicator::isend_vector(int dest, int tag, const std::vector<T,A>& values,
mpl::true_ primitive) const
{
return request::make_dynamic_primitive_array_send(*this, dest, tag, values);
}
template<typename T, class A>
request
communicator::isend_vector(int dest, int tag, const std::vector<T,A>& values,
mpl::false_ no) const
{
return this->isend_impl(dest, tag, values, no);
}
template<typename T>
request
communicator::array_isend_impl(int dest, int tag, const T* values, int n,
mpl::true_) const
{
return request::make_trivial_send(*this, dest, tag, values, n);
}
template<typename T>
request
communicator::array_isend_impl(int dest, int tag, const T* values, int n,
mpl::false_) const
{
shared_ptr<packed_oarchive> archive(new packed_oarchive(*this));
T const* v = values;
while (v < values+n) {
*archive << *v++;
}
request result = isend(dest, tag, *archive);
result.preserve(archive);
return result;
}
// Array isend must send the elements directly
template<typename T>
request communicator::isend(int dest, int tag, const T* values, int n) const
{
return array_isend_impl(dest, tag, values, n, is_mpi_datatype<T>());
}
// We're receiving a type that has an associated MPI datatype, so we
// map directly to that datatype.
template<typename T>
request
communicator::irecv_impl(int source, int tag, T& value, mpl::true_) const
{
return request::make_trivial_recv(*this, source, tag, value);
}
template<typename T>
request
communicator::irecv_impl(int source, int tag, T& value, mpl::false_) const
{
return request::make_serialized(*this, source, tag, value);
}
template<typename T>
request
communicator::irecv(int source, int tag, T& value) const
{
return this->irecv_impl(source, tag, value, is_mpi_datatype<T>());
}
template<typename T>
request
communicator::array_irecv_impl(int source, int tag, T* values, int n,
mpl::true_) const
{
return request::make_trivial_recv(*this, source, tag, values, n);
}
template<typename T>
request
communicator::array_irecv_impl(int source, int tag, T* values, int n,
mpl::false_) const
{
return request::make_serialized_array(*this, source, tag, values, n);
}
template<typename T, class A>
request
communicator::irecv_vector(int source, int tag, std::vector<T,A>& values,
mpl::true_ primitive) const
{
return request::make_dynamic_primitive_array_recv(*this, source, tag, values);
}
template<typename T, class A>
request
communicator::irecv_vector(int source, int tag, std::vector<T,A>& values,
mpl::false_ no) const
{
return irecv_impl(source, tag, values, no);
}
template<typename T, typename A>
request
communicator::irecv(int source, int tag, std::vector<T,A>& values) const
{
return irecv_vector(source, tag, values, is_mpi_datatype<T>());
}
// Array receive must receive the elements directly into a buffer.
template<typename T>
request communicator::irecv(int source, int tag, T* values, int n) const
{
return this->array_irecv_impl(source, tag, values, n, is_mpi_datatype<T>());
}
} } // end namespace boost::mpi
// If the user has already included skeleton_and_content.hpp, include
// the code to send/receive skeletons and content.
#ifdef BOOST_MPI_SKELETON_AND_CONTENT_HPP
# include <boost/mpi/detail/communicator_sc.hpp>
#endif
#ifdef BOOST_MSVC
# pragma warning(pop)
#endif
#endif // BOOST_MPI_COMMUNICATOR_HPP
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