mp_alltoall_d Subroutine

private subroutine mp_alltoall_d(sb, rb, count, group)

All-to-all data exchange, rank 1 arrays, equal sizes

Index meaning

The first two indices specify the data while the last index counts the processes

Sizes of ranks All processes have the same data size.

MPI mapping mpi_alltoall

Arguments

TypeIntentOptionalAttributesName
real(kind=real_8), intent(in), CONTIGUOUS:: sb(:)

array with data to send

real(kind=real_8), intent(out), CONTIGUOUS:: rb(:)

array into which data is received

integer, intent(in) :: count

number of elements to send/receive (product of the extents of the first two dimensions) Message passing environment identifier

integer, intent(in) :: group

number of elements to send/receive (product of the extents of the first two dimensions) Message passing environment identifier


Contents

Source Code


Source Code

      SUBROUTINE mp_alltoall_d (sb, rb, count, group)
      !! All-to-all data exchange, rank 1 arrays, equal sizes
      !!
      !! Index meaning
      !!
      !! The first two indices specify the data while the last index counts
      !! the processes
      !!
      !! Sizes of ranks
      !! All processes have the same data size.
      !!
      !! MPI mapping
      !! mpi_alltoall

         REAL(kind=real_8), CONTIGUOUS, INTENT(IN)        :: sb(:)
         !! array with data to send
         REAL(kind=real_8), CONTIGUOUS, INTENT(OUT)       :: rb(:)
         !! array into which data is received
         INTEGER, INTENT(IN)                      :: count, group
         !! number of elements to send/receive (product of the extents of the first two dimensions)
         !! Message passing environment identifier

         CHARACTER(LEN=*), PARAMETER :: routineN = 'mp_alltoall_d'

         INTEGER                                  :: handle, ierr
#if defined(__parallel)
         INTEGER                                  :: msglen, np
#endif

         ierr = 0
         CALL timeset(routineN, handle)

#if defined(__parallel)
         CALL mpi_alltoall(sb, count, MPI_DOUBLE_PRECISION, &
                           rb, count, MPI_DOUBLE_PRECISION, group, ierr)
         IF (ierr /= 0) CALL mp_stop(ierr, "mpi_alltoall @ "//routineN)
         CALL mpi_comm_size(group, np, ierr)
         IF (ierr /= 0) CALL mp_stop(ierr, "mpi_comm_size @ "//routineN)
         msglen = 2*count*np
         CALL add_perf(perf_id=6, msg_size=msglen*real_8_size)
#else
         MARK_USED(count)
         MARK_USED(group)
         rb = sb
#endif
         CALL timestop(handle)

      END SUBROUTINE mp_alltoall_d