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Added comments and license for implMpi

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Benjamin Bouvier 2012-07-24 17:38:54 +02:00
commit 8b1d376557
1 changed files with 198 additions and 5 deletions
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203
eo/src/mpi/implMpi.h
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@ -1,31 +1,115 @@
# ifndef __EO_MPI_HPP__
# define __EO_MPI_HPP__
/*
(c) Thales group, 2012
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation;
version 2 of the License.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Contact: http://eodev.sourceforge.net
Authors:
Benjamin Bouvier <benjamin.bouvier@gmail.com>
*/
# ifndef __EO_IMPL_MPI_HPP__
# define __EO_IMPL_MPI_HPP__
# include <mpi.h>
# include <serial/eoSerial.h>
/**
* This namespace contains reimplementations of some parts of the Boost::MPI API in C++, so as to be used in
* EO without any dependance to Boost. Historically, EO's parallelization module used the
* boost library to add a layer over MPI. After having noticed that just some functions
* were really used, we decided to reimplement our own C++-like implementation of MPI.
*
* Because the Boost::MPI API is really clean, we reused it in this module. However, all
* the functions of Boost::MPI were not used, hence a subset of the API is reused. For
* instance, users can just send integer, std::string or eoserial::Persistent objects;
* furthermore, only eoserial::Persistent objects can sent in a table.
*
* The documentation of the functions is exactly the same as the official Boost::MPI
* documentation. You can find it on www.boost.org/doc/libs/1_49_0/doc/html/mpi/
* The entities are here shortly described, if you need further details, don't hesitate
* to visit the boost URL.
*/
namespace mpi
{
/**
* @ingroup Parallel
* @{
*/
/**
* @brief Constant indicating that a message can come from any process.
*/
extern const int any_source;
/**
* @brief Constant indicating that a message can come from any tag (channel).
*/
extern const int any_tag;
/**
* @brief Wrapper class to have a MPI environment.
*
* Instead of calling MPI_Init and MPI_Finalize, it is only necessary to instantiate
* this class once, in the global context.
*/
class environment
{
public:
/**
* @brief Inits MPI context.
*
* @param argc Number of params in command line (same as one in main)
* @param argv Strings containing params (same as one in main)
*/
environment(int argc, char**argv);
/**
* @brief Closes MPI context.
*/
~environment();
};
/**
* @brief Wrapper class for MPI_Status
*
* Consists only in a C++ wrapper class, giving getters on status attributes.
*/
class status
{
public:
/**
* @brief Converts a MPI_Status into a status.
*/
status( const MPI_Status & s );
/**
* @brief Returns the tag of the associated communication.
*/
int tag() { return _tag; }
/**
* @brief Indicates which error number we obtained in the associated communication.
*/
int error() { return _error; }
/**
* @brief Returns the MPI rank of the source of the associated communication.
*/
int source() { return _source; }
private:
@ -34,37 +118,99 @@ namespace mpi
int _error;
};
/**
* @brief Main object, used to send / receive messages, get informations about the rank and the size of the world,
* etc.
*/
class communicator
{
public:
/**
* Creates the communicator, using the whole world as a MPI_Comm.
*
* @todo Allow the user to precise which MPI_Comm to use
*/
communicator( );
~communicator();
/**
* @brief Returns the MPI rank of the current process.
*/
int rank();
/**
* @brief Returns the size of the MPI cluster.
*/
int size();
/*
* SEND / RECV INT
*/
/**
* @brief Sends an integer to dest on channel "tag".
*
* @param dest MPI rank of the receiver
* @param tag MPI tag of message
* @param n The integer to send
*/
void send( int dest, int tag, int n );
/*
* @brief Receives an integer from src on channel "tag".
*
* @param src MPI rank of the sender
* @param tag MPI tag of message
* @param n Where to save the received integer
*/
void recv( int src, int tag, int& n );
/*
* SEND / RECV STRING
*/
/**
* @brief Sends a string to dest on channel "tag".
*
* @param dest MPI rank of the receiver
* @param tag MPI tag of message
* @param str The std::string to send
*/
void send( int dest, int tag, const std::string& str );
/*
* @brief Receives a string from src on channel "tag".
*
* @param src MPI rank of the sender
* @param tag MPI tag of message
* @param std::string Where to save the received string
*/
void recv( int src, int tag, std::string& str );
/*
* SEND / RECV Objects
*/
/**
* @brief Sends an eoserial::Persistent to dest on channel "tag".
*
* @param dest MPI rank of the receiver
* @param tag MPI tag of message
* @param persistent The object to send (it must absolutely implement eoserial::Persistent)
*/
void send( int dest, int tag, const eoserial::Persistent & persistent );
/**
* @brief Sends an array of eoserial::Persistent to dest on channel "tag".
*
* @param dest MPI rank of the receiver
* @param tag MPI tag of message
* @param table The array of eoserial::Persistent objects
* @param size The number of elements to send (no check is done, the user has to be sure that the size won't
* overflow!)
*/
template< class T >
void send( int dest, int tag, T* table, int size )
{
@ -87,8 +233,25 @@ namespace mpi
send( dest, tag, ss.str() );
}
/*
* @brief Receives an eoserial::Persistent object from src on channel "tag".
*
* @param src MPI rank of the sender
* @param tag MPI tag of message
* @param persistent Where to unpack the serialized object?
*/
void recv( int src, int tag, eoserial::Persistent & persistent );
/*
* @brief Receives an array of eoserial::Persistent from src on channel "tag".
*
* @param src MPI rank of the sender
* @param tag MPI tag of message
* @param table The table in which we're saving the received objects. It must have been allocated by the user,
* as no allocation is performed here.
* @param size The number of elements to receive (no check is done, the user has to be sure that the size won't
* overflow!)
*/
template< class T >
void recv( int src, int tag, T* table, int size )
{
@ -111,19 +274,49 @@ namespace mpi
/*
* Other methods
*/
/**
* @brief Wrapper for MPI_Probe
*
* Waits for a message to come from process having rank src, on the channel
* tag.
*
* @param src MPI rank of the sender (any_source if it can be any sender)
* @param tag MPI tag of the expected message (any_tag if it can be any tag)
*/
status probe( int src = any_source, int tag = any_tag );
/**
* @brief Wrapper for MPI_Barrier
*
*
*/
void barrier();
private:
int _rank;
int _size;
char* _buf;
int _bufsize;
char* _buf; // temporary buffer for sending and receiving strings. Avoids reallocations
int _bufsize; // size of the above temporary buffer
};
/**
* @brief Wrapper for MPI_Bcast
*
* Broadcasts an integer value on the communicator comm, from the process having the MPI rank root.
*
* @param comm The communicator on which to broadcast
* @param value The integer value to send
* @param root The MPI rank of the broadcaster
*
* @todo Actually comm isn't used and broadcast is performed on the whole MPI_COMM_WORLD. TODO: Use comm instead
*/
void broadcast( communicator & comm, int value, int root );
/**
* @}
*/
} // namespace mpi
# endif //__EO_MPI_HPP__
# endif //__EO_IMPL_MPI_HPP__