MPI_Reduce_scatter man page on RedHat

Man page or keyword search:  
man Server   29550 pages
apropos Keyword Search (all sections)
Output format
RedHat logo
[printable version]

MPI_Reduce_scatter(3)		      MPI		 MPI_Reduce_scatter(3)

NAME
       MPI_Reduce_scatter -  Combines values and scatters the results

SYNOPSIS
       int MPI_Reduce_scatter(const void *sendbuf, void *recvbuf, const int recvcounts[],
			     MPI_Datatype datatype, MPI_Op op, MPI_Comm comm)

INPUT PARAMETERS
       sendbuf
	      - starting address of send buffer (choice)
       recvcounts
	      - integer array specifying the number of elements in result dis‐
	      tributed to each process.	 Array must be identical on all	 call‐
	      ing processes.
       datatype
	      - data type of elements of input buffer (handle)
       op     - operation (handle)
       comm   - communicator (handle)

OUTPUT PARAMETERS
       recvbuf
	      - starting address of receive buffer (choice)

THREAD AND INTERRUPT SAFETY
       This  routine  is  thread-safe.	 This  means  that this routine may be
       safely used by multiple threads without the need for any	 user-provided
       thread  locks.  However, the routine is not interrupt safe.  Typically,
       this is due to the use of memory allocation routines such as malloc  or
       other  non-MPICH	 runtime  routines  that are themselves not interrupt-
       safe.

NOTES FOR FORTRAN
       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK )  have
       an  additional  argument ierr at the end of the argument list.  ierr is
       an integer and has the same meaning as the return value of the  routine
       in  C.	In Fortran, MPI routines are subroutines, and are invoked with
       the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
       Fortran.

NOTES ON COLLECTIVE OPERATIONS
       The  reduction functions ( MPI_Op ) do not return an error value.  As a
       result, if the functions detect an error, all they  can	do  is	either
       call  MPI_Abort	or silently skip the problem.  Thus, if you change the
       error handler from MPI_ERRORS_ARE_FATAL to something else, for example,
       MPI_ERRORS_RETURN , then no error may be indicated.

       The  reason  for	 this is the performance problems in ensuring that all
       collective routines return the same error value.

ERRORS
       All MPI routines (except MPI_Wtime and  MPI_Wtick  )  return  an	 error
       value;  C routines as the value of the function and Fortran routines in
       the last argument.  Before the value is returned, the current MPI error
       handler	is called.  By default, this error handler aborts the MPI job.
       The error handler may be changed with MPI_Comm_set_errhandler (for com‐
       municators),	 MPI_File_set_errhandler      (for     files),	   and
       MPI_Win_set_errhandler  (for   RMA   windows).	 The   MPI-1   routine
       MPI_Errhandler_set  may	be used but its use is deprecated.  The prede‐
       fined error handler MPI_ERRORS_RETURN may be used to cause error values
       to  be  returned.  Note that MPI does not guarentee that an MPI program
       can continue past an error; however, MPI implementations	 will  attempt
       to continue whenever possible.

       MPI_SUCCESS
	      - No error; MPI routine completed successfully.
       MPI_ERR_COMM
	      -	 Invalid communicator.	A common error is to use a null commu‐
	      nicator in a call (not even allowed in MPI_Comm_rank ).
       MPI_ERR_COUNT
	      - Invalid count argument.	 Count arguments must be non-negative;
	      a count of zero is often valid.
       MPI_ERR_TYPE
	      - Invalid datatype argument.  May be an uncommitted MPI_Datatype
	      (see MPI_Type_commit ).
       MPI_ERR_BUFFER
	      - Invalid buffer pointer.	 Usually a null buffer	where  one  is
	      not valid.
       MPI_ERR_OP
	      -	 Invalid  operation.  MPI operations (objects of type MPI_Op )
	      must either be one of the predefined operations (e.g., MPI_SUM )
	      or created with MPI_Op_create .

       MPI_ERR_BUFFER
	      -	 This error class is associcated with an error code that indi‐
	      cates that two buffer arguments  are  aliased  ;	that  is,  the
	      describe	overlapping  storage  (often  the exact same storage).
	      This is prohibited in MPI (because it is prohibited by the  For‐
	      tran  standard,  and  rather than have a separate case for C and
	      Fortran, the MPI Forum adopted the more restrictive requirements
	      of Fortran).

LOCATION
       src/mpi/coll/red_scat.c

				   8/22/2013		 MPI_Reduce_scatter(3)
[top]

List of man pages available for RedHat

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net