plucky (3) MPI_Intercomm_create.3.gz

NAME

       MPI_Intercomm_create -  Creates an intercommuncator from two intracommunicators

SYNOPSIS

       #include <mpi.h>
       int MPI_Intercomm_create(MPI_Comm lcomm, int lleader,
                              MPI_Comm pcomm, int pleader, int tag,
                              MPI_Comm *newcomm)

INPUT PARAMTERS

       lcomm  - Local (intra)communicator
       lleader
              - Rank in local_comm of leader (often 0)
       pcomm  - Remote communicator
       pleader
              - Rank in peer_comm of remote leader (often 0)
       tag    -  Message  tag  to  use  in constructing intercommunicator; if multiple MPI_Intercomm_creates are
              being made, they should use different tags (more precisely,  ensure  that  the  local  and  remote
              leaders are using different tags for each MPI_intercomm_create ).

OUTPUT PARAMETER

       newcomm
              - Created intercommunicator

NOTES

       The  MPI 1.1 Standard contains two mutually exclusive comments on the input intracommunicators.  One says
       that their repective groups must be disjoint; the other that the leaders can be the same process.   After
       some  discussion  by  the MPI Forum, it has been decided that the groups must be disjoint.  Note that the
       reason given for this in the standard is not the reason for this choice; rather, the other operations  on
       intercommunicators (like MPI_Intercomm_merge ) do not make sense if the groups are not disjoint.

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.

ERRORS

       If an error occurs in an MPI function, the current MPI error handler is called to handle it.  By default,
       this error handler aborts the MPI job.  The error handler may be changed with  MPI_Errhandler_set  ;  the
       predefined  error  handler  MPI_ERRORS_RETURN  may be used to cause error values to be returned (in C and
       Fortran; this error handler is less useful in with the C++ MPI bindings.  The  predefined  error  handler
       MPI::ERRORS_THROW_EXCEPTIONS  should be used in C++ if the error value needs to be recovered).  Note that
       MPI does not guarantee that an MPI program can continue past an error.

       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.  The C++ bindings for MPI do not return error values;
       instead, error values are communicated  by  throwing  exceptions  of  type  MPI::Exception  (but  not  by
       default).  Exceptions are only thrown if the error value is not MPI::SUCCESS .

       Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return upon an error,
       there will be no way to recover what the actual error value was.
       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_COMM
              - Invalid communicator.  A common error is to use a null communicator in a call (not even  allowed
              in MPI_Comm_rank ).
       MPI_ERR_TAG
              -  Invalid  tag  argument.   Tags must be non-negative; tags in a receive ( MPI_Recv , MPI_Irecv ,
              MPI_Sendrecv , etc.)  may also be MPI_ANY_TAG .  The largest tag value is  available  through  the
              the attribute MPI_TAG_UB .

       MPI_ERR_ARG
              -  Invalid  argument.   Some  argument is invalid and is not identified by a specific error class.
              This is typically a NULL pointer or other such error.
       MPI_ERR_OTHER
              - This error is returned when some part of the LAM/MPI implementation is unable to acquire memory.
       MPI_ERR_RANK
              - Invalid source or destination rank.  Ranks must be between zero and the size of the communicator
              minus  one;  ranks  in  a  receive  (  MPI_Recv  ,  MPI_Irecv  ,  MPI_Sendrecv , etc.) may also be
              MPI_ANY_SOURCE .

SEE ALSO

       MPI_Intercomm_merge, MPI_Comm_free, MPI_Comm_remote_group,
       MPI_Comm_remote_size

MORE INFORMATION

       For more information, please see the official MPI Forum web site, which contains the  text  of  both  the
       MPI-1 and MPI-2 standards.  These documents contain detailed information about each MPI function (most of
       which is not duplicated in these man pages).

       http://www.mpi-forum.org/

ACKNOWLEDGEMENTS

       The LAM Team would like the thank the MPICH Team for the handy program to generate man  pages  ("doctext"
       from  ftp://ftp.mcs.anl.gov/pub/sowing/sowing.tar.gz ), the initial formatting, and some initial text for
       most of the MPI-1 man pages.

LOCATION

       iccreate.c