MPIGroupunion(3OpenMPI) MPIGroupunion(3OpenMPI)

NAME
       MMPPIIGGrroouuppuunniioonn  - Produces a group by combining two groups.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPIGroupunion(MPIGroup group1, MPIGroup group2,
            MPIGroup *newgroup)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPIGROUPUNION(GROUP1, GROUP2, NEWGROUP, IERROR)
            INTEGER   GROUP1, GROUP2, NEWGROUP, IERROR


CC++++ SSyynnttaaxx
       #include 
       static Group Group::Union(const Group& group1, const Group& group2)


IINNPPUUTT PPAARRAAMMEETTEERRSS
       group1    First group (handle).

       group2    Second group (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       newgroup  Union group (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       The set-like operations are defined as follows:

         o    union  -  All elements of the first group (group1), followed by
              all elements of second group (group2) not in first.

         o    intersect - all elements of the first group that  are  also  in
              the second group, ordered as in first group.

         o    difference  -  all  elements of the first group that are not in
              the second group, ordered as in the first group.


       Note that for these operations the order of  processes  in  the  output
       group is determined primarily by order in the first group (if possible)
       and then, if necessary, by order in the second group. Neither union nor
       intersection are commutative, but both are associative.

       The new group can be empty, that is, equal to MPIGROUPEMPTY.


EERRRROORRSS
       Almost  all MPI routines return an error value; C routines as the value
       of the function and Fortran routines in the last  argument.  C++  func-
       tions  do  not  return  errors.  If the default error handler is set to
       MPI::ERRORSTHROWEXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before  the  error  value is returned, the current MPI error handler is
       called. By default, this error handler aborts the MPI job,  except  for
       I/O   function   errors.   The   error  handler  may  be  changed  with
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       may  be  used  to cause error values to be returned. Note that MPI does
       not guarantee that an MPI program can continue past an error.


SEE ALSO
       MPIGroupfree




Open MPI 1.2                    September 2006       MPIGroupunion(3OpenMPI)