pvm_bcast(3pvm) [linux man page]

BCAST(3PVM)							  PVM Version 3.4						       BCAST(3PVM)

NAME

       pvm_bcast - Broadcasts the data in the active message buffer to a group of processes.

SYNOPSIS

       C    int info = pvm_bcast( char *group, int msgtag )

       Fortran	 call pvmfbcast( group, msgtag, info )

PARAMETERS

       group   Character string group name of an existing group.

       msgtag  Integer	message  tag  supplied by the user.  msgtag should be >= 0.  It allows the user's program to distinguish between different
	       kinds of messages .
	       info integer status code returned by the routine.  Values less than zero indicate an error.

DESCRIPTION

       The routine pvm_bcast broadcasts a message stored in the active send buffer to all the members of group.  In PVM 3.2 and later  the  broad-
       cast  message is not sent back to the sender.  Any PVM task can call pvm_bcast(), it need not be a member of the group.	The content of the
       message can be distinguished by msgtag.	If pvm_bcast is successful, info will be 0. If some error occurs then info will be < 0.

       pvm_bcast is asynchronous.  Computation on the sending processor resumes as soon as the message is safely on its way to the receiving  pro-
       cessors.   This	is  in	contrast  to  synchronous  communication, during which computation on the sending processor halts until a matching
       receive is executed by all the receiving processors.

       pvm_bcast first determines the tids of the group members by checking a group data base.	A multicast is performed to these  tids.   If  the
       group  is changed during a broadcast the change will not be reflected in the broadcast.	Multicasting is not supported by most multiproces-
       sor vendors.  Typically their native calls only support broadcasting to all the user's processes on a multiprocessor. Because of this omis-
       sion, pvm_bcast may not be an efficient communication method on some multiprocessors.

EXAMPLES

       C:
	    info = pvm_initsend( PvmDataRaw );
	    info = pvm_pkint( array, 10, 1 );
	    msgtag = 5 ;
	    info = pvm_bcast( "worker", msgtag );

       Fortran:
	    CALL PVMFINITSEND( PVMDEFAULT )
	    CALL PVMFPKFLOAT( DATA, 100, 1, INFO )
	    CALL PVMFBCAST( 'worker', 5, INFO )

ERRORS

       These error conditions can be returned by pvm_bcast

       PvmSysErr
	      pvmd was not started or has crashed.

       PvmBadParam
	      giving a negative msgtag.

       PvmNoGroup
	      giving a non-existent group name.

SEE ALSO

       pvm_joingroup(3PVM)

								  30 August, 1993						       BCAST(3PVM)

MCAST(3PVM)							  PVM Version 3.4						       MCAST(3PVM)

NAME

       pvm_mcast - Multicasts the data in the active message buffer to a set of tasks.

SYNOPSIS

       C    int info = pvm_mcast( int *tids, int ntask, int msgtag )

       Fortran	 call pvmfmcast( ntask, tids, msgtag, info )

PARAMETERS

       ntask   Integer specifying the number of tasks to be sent to.

       tids    Integer array of length ntask containing the task IDs of the tasks to be sent to.

       msgtag  Integer	message  tag  supplied by the user.  msgtag should be >= 0.  It allows the user's program to distinguish between different
	       kinds of messages .

       info    Integer status code returned by the routine.  Values less than zero indicate an error.

DESCRIPTION

       The routine pvm_mcast multicasts a message stored in the active send buffer to ntask tasks specified in the tids array.	The message is not
       sent  to  the caller even if listed in the array of tids.  The content of the message can be distinguished by msgtag.  If pvm_mcast is suc-
       cessful, info will be 0. If some error occurs then info will be < 0.

       The receiving processes can call either pvm_recv or pvm_nrecv to receive their copy of the multicast.  pvm_mcast is asynchronous and  based
       on  a  minimum spanning tree algorithm between the pvmds.  Computation on the sending processor resumes as soon as the message is safely on
       its way to the receiving processors.  This is in contrast to synchronous communication, during which computation on the	sending  processor
       halts until the matching receive is executed by the receiving processor.

       pvm_mcast  first determines which other pvmds contain the specified tasks.  Then passes the message to these pvmds which in turn distribute
       the message to their local tasks without further network traffic.

       Multicasting is not supported by most multiprocessor vendors.  Typically their native calls only support broadcasting to {m all the user's
       processes  on  a  multiprocessor.  Because of this omission, pvm_mcast may not be an efficient communication method on some multiprocessors
       except in the special case of broadcasting to all PVM processes.

EXAMPLES

       C:
	    info = pvm_initsend( PvmDataRaw );
	    info = pvm_pkint( array, 10, 1 );
	    msgtag = 5 ;
	    info = pvm_mcast( tids, ntask, msgtag );

       Fortran:
	    CALL PVMFINITSEND(PVMDEFAULT)
	    CALL PVMFPACK( REAL4, DATA, 100, 1, INFO )
	    CALL PVMFMCAST( NPROC, TIDS, 5, INFO )

ERRORS

       These error conditions can be returned by pvm_mcast

       PvmBadParam
	      giving a msgtag < 0.

       PvmSysErr
	      pvmd not responding.

       PvmNoBuf
	      no send buffer.

SEE ALSO

       pvm_psend(3PVM), pvm_recv(3PVM), pvm_send(3PVM)

								  30 August, 1993						       MCAST(3PVM)