src/Message/CommMPI.h

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// -*- C++ -*-
/***************************************************************************
 *
 * The IPPL Framework
 * 
 *
 * Visit http://people.web.psi.ch/adelmann/ for more details
 *
 ***************************************************************************/

#ifndef COMM_MPI_H
#define COMM_MPI_H

/***************************************************************************
 * CommMPI.h - MPI-specific communications object for use with the
 * Ippl framework.
 * Allows user to establish id's for available nodes, establish connections,
 * and send/receive data.
 ***************************************************************************/

// include files
#include "Message/Communicate.h"
#include <mpi.h>


class CommMPI : public Communicate {

public:
  // constructor and destructor
  // constructor arguments: command-line args, and number of processes
  // to start (if < 0, start the 'default' number, i.e. the number of
  // hosts in a MPI virtual machine, the number of nodes in an O2K, etc)
  CommMPI(int& argc, char**& argv, int procs = (-1), bool mpiinit = true);
  virtual ~CommMPI(void);

  // return the name of this item
  virtual const char *name() const { return "MPI"; }

  //
  //    virtual routines to deal with memory management
  //

  // clean up after a Message has been used (called by Message).
  virtual void cleanupMessage(void *);

protected:

  //
  // implementation-specific routines (which begin with 'my')
  //    these should be provided in a derived class, and contain the
  //    comm-library-specific code
  //

  // send a message ... arguments are the Message itself, the
  // destination node, the 'user' tag, and the 'encoding' tag.
  // Messages should be sent via the underlying mechanism by using the
  // encoding tag (one of the COMM_ tags),
  // and should embed the information about what the user
  // tag is in the data sent between nodes.  Return success.
  virtual bool mysend(Message *, int node, int utag, int etag);

  // receive a message from the given node and user tag.  Return a NEW
  // Message object if a message arrives, or NULL if no message available.
  // node will be set to the node from which the message was sent.
  // tag will be set to the 'user tag' for that message.
  // etag is the 'encoding' tag, and must be one of the COMM_ tags. 
  // Only message sent via the underlying mechanism with the
  // given etag are checked.  When one is found, the user tag and sending
  // node are extracted from the sent data.
  // If node = COMM_ANY_NODE, checks for messages from any node.
  // If tag = COMM_ANY_TAG, checks for messages with any user tag.
  virtual Message *myreceive(int& node, int& tag, int etag);

  // Synchronize all processors (everybody waits for everybody
  // else to get here before returning to calling function).
  virtual void mybarrier(void);

  // resent a message buffer that has been previously packed and copied
  // into the provided buffer.  Return success.
  virtual bool resend(void *buf, int size, int node, int etag);

private:
  // an MPI communicator for this object to use, to avoid interfering
  // with other MPI usage.
  MPI_Comm communicator;

  // a flag indicating whether we initialized the communication or not.
  bool weInitialized;

  // take data from the given Message, and pack it into the current send buf
  void *pack_message(Message *msg, int tag, int &buffsize, int node);
};


#endif // COMM_MPI_H

/***************************************************************************
 * $RCSfile: CommMPI.h,v $   $Author: adelmann $
 * $Revision: 1.1.1.1 $   $Date: 2003/01/23 07:40:28 $
 * IPPL_VERSION_ID: $Id: CommMPI.h,v 1.1.1.1 2003/01/23 07:40:28 adelmann Exp $ 
 ***************************************************************************/

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