oracular (3) MPI_Group_range_incl.openmpi.3.gz

NAME

       MPI_Group_range_incl - Creates a new group from ranges of ranks in an existing group.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Group_range_incl(MPI_Group group, int n, int ranges[][3],
            MPI_Group *newgroup)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_GROUP_RANGE_INCL(GROUP, N, RANGES, NEWGROUP, IERROR)
            INTEGER   GROUP, N, RANGES(3,*), NEWGROUP, IERROR

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Group_range_incl(group, n, ranges, newgroup, ierror)
            TYPE(MPI_Group), INTENT(IN) :: group
            INTEGER, INTENT(IN) :: n, ranges(3,n)
            TYPE(MPI_Group), INTENT(OUT) :: newgroup
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

       #include <mpi.h>
       Group Group::Range_incl(int n, const int ranges[][3]) const

INPUT PARAMETERS

       group     Group (handle).

       n         Number of triplets in array ranges (integer).

       ranges    A  one-dimensional  array  of  integer  triplets,  of  the form (first rank, last rank, stride)
                 indicating ranks in group or processes to be included in newgroup.

OUTPUT PARAMETERS

       newgroup  New group derived from above, in the order defined by ranges (handle).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       If ranges consist of the triplets

           (first1, last1, stride1), ..., (firstn, lastn, striden)

       then newgroup consists of the sequence of processes in group with ranks

                                                        last(1)-first(1)
         first(1), first(1) + stride(1),..., first(1) + ---------------- stride(1),...
                                                            stride(1)

                                                        last(n)-first(n)
         first(n), first(n) + stride(n),..., first(n) + ---------------- stride(n).
                                                            stride(n)

       Each computed rank must be a valid rank in group and all computed ranks must be  distinct,  or  else  the
       program is erroneous. Note that we may have first(i) > last(i), and stride(i) may be negative, but cannot
       be zero.

       The functionality of this routine is specified to be equivalent to expanding the array of  ranges  to  an
       array  of  the  included  ranks  and  passing  the  resulting  array  of  ranks  and  other  arguments to
       MPI_Group_incl. A call to MPI_Group_incl is equivalent to a call to MPI_Group_range_incl with each rank i
       in ranks replaced by the triplet (i,i,1) in the argument ranges.

NOTE

       This implementation does not currently check to see that the list of ranges to include are valid ranks in
       the group.

ERRORS

       Almost all MPI routines return an error value; C routines as  the  value  of  the  function  and  Fortran
       routines in the last argument. C++ functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, 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
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN 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

       MPI_Group_incl
       MPI_Group_free