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!BOP
<A NAME='ICE_COMMUNICATE'><A href='../../html_code/cice/ice_communicate.F90.html#ICE_COMMUNICATE' TARGET='top_target'><IMG SRC="../../gif/bar_purple.gif" border=0></A>
module ice_communicate 37,1
! !MODULE: ice_communicate
! !DESCRIPTION:
! This module contains the necessary routines and variables for
! communicating between processors.
!
! !REVISION HISTORY:
! SVN:$Id: ice_communicate.F90 127 2008-04-28 21:59:36Z eclare $
!
! author: Phil Jones, LANL
! Oct. 2004: Adapted from POP version by William H. Lipscomb, LANL
!
! !USES:
use ice_kinds_mod
#if defined key_oasis3
use cpl_oasis3
#endif
#if defined key_oasis4
use cpl_oasis4
#endif
implicit none
private
save
! !PUBLIC MEMBER FUNCTIONS:
public :: init_communicate, &
get_num_procs, &
create_communicator
! !PUBLIC DATA MEMBERS:
integer (int_kind), public :: &
MPI_COMM_ICE, &! MPI communicator for ice comms
mpiR16, &! MPI type for r16_kind
mpiR8, &! MPI type for dbl_kind
mpiR4, &! MPI type for real_kind
my_task, &! MPI task number for this task
master_task ! task number of master task
integer (int_kind), parameter, public :: &
mpitagHalo = 1, &! MPI tags for various
mpitag_gs = 1000 ! communication patterns
!EOP
!BOC
!EOC
!***********************************************************************
contains
!***********************************************************************
!BOP
! !IROUTINE: init_communicate
! !INTERFACE:
<A NAME='INIT_COMMUNICATE'><A href='../../html_code/cice/ice_communicate.F90.html#INIT_COMMUNICATE' TARGET='top_target'><IMG SRC="../../gif/bar_red.gif" border=0></A>
subroutine init_communicate 2,1
! !DESCRIPTION:
! This routine sets up MPI environment and defines ice
! communicator.
!
! !REVISION HISTORY:
! same as module
!EOP
!BOC
!-----------------------------------------------------------------------
!
! local variables
!
!-----------------------------------------------------------------------
include 'mpif.h' ! MPI Fortran include file
integer (int_kind) :: ierr ! MPI error flag
integer (int_kind) :: ice_comm
!-----------------------------------------------------------------------
!
! initiate mpi environment and create communicator for internal
! ice communications
!
!-----------------------------------------------------------------------
#if (defined key_oasis3 || defined key_oasis4)
ice_comm = localComm ! communicator from NEMO/OASISn
#else
ice_comm = MPI_COMM_WORLD ! Global communicator
#endif
#if (defined popcice || defined CICE_IN_NEMO)
! MPI_INIT is called elsewhere in coupled configuration
#else
call MPI_INIT(ierr)
#endif
call MPI_BARRIER (ice_comm, ierr)
call MPI_COMM_DUP(ice_comm, MPI_COMM_ICE, ierr)
master_task = 0
call MPI_COMM_RANK (MPI_COMM_ICE, my_task, ierr)
mpiR16 = MPI_REAL16
mpiR8 = MPI_REAL8
mpiR4 = MPI_REAL4
!-----------------------------------------------------------------------
!EOC
end subroutine init_communicate
!***********************************************************************
!BOP
! !IROUTINE: get_num_procs
! !INTERFACE:
<A NAME='GET_NUM_PROCS'><A href='../../html_code/cice/ice_communicate.F90.html#GET_NUM_PROCS' TARGET='top_target'><IMG SRC="../../gif/bar_green.gif" border=0></A>
function get_num_procs() 10,1
! !DESCRIPTION:
! This function returns the number of processor assigned to
! MPI_COMM_ICE
!
! !REVISION HISTORY:
! same as module
! !OUTPUT PARAMETERS:
integer (int_kind) :: get_num_procs
!EOP
!BOC
!-----------------------------------------------------------------------
!
! local variables
!
!-----------------------------------------------------------------------
integer (int_kind) :: ierr
!-----------------------------------------------------------------------
call MPI_COMM_SIZE(MPI_COMM_ICE, get_num_procs, ierr)
!-----------------------------------------------------------------------
!EOC
end function get_num_procs
!***********************************************************************
!BOP
! !IROUTINE: create_communicator
! !INTERFACE:
<A NAME='CREATE_COMMUNICATOR'><A href='../../html_code/cice/ice_communicate.F90.html#CREATE_COMMUNICATOR' TARGET='top_target'><IMG SRC="../../gif/bar_red.gif" border=0></A>
subroutine create_communicator(new_comm, num_procs) 4,1
! !DESCRIPTION:
! This routine creates a separate communicator for a subset of
! processors under default ice communicator.
!
! this routine should be called from init_domain1 when the
! domain configuration (e.g. nprocs_btrop) has been determined
!
! !REVISION HISTORY:
! same as module
! !INCLUDES:
include 'mpif.h'
! !INPUT PARAMETERS:
integer (int_kind), intent(in) :: &
num_procs ! num of procs in new distribution
! !OUTPUT PARAMETERS:
integer (int_kind), intent(out) :: &
new_comm ! new communicator for this distribution
!EOP
!BOC
!-----------------------------------------------------------------------
!
! local variables
!
!-----------------------------------------------------------------------
integer (int_kind) :: &
MPI_GROUP_ICE, &! group of processors assigned to ice
MPI_GROUP_NEW ! group of processors assigned to new dist
integer (int_kind) :: &
ierr ! error flag for MPI comms
integer (int_kind), dimension(3) :: &
range ! range of tasks assigned to new dist
! (assumed 0,num_procs-1)
!-----------------------------------------------------------------------
!
! determine group of processes assigned to distribution
!
!-----------------------------------------------------------------------
call MPI_COMM_GROUP (MPI_COMM_ICE, MPI_GROUP_ICE, ierr)
range(1) = 0
range(2) = num_procs-1
range(3) = 1
!-----------------------------------------------------------------------
!
! create subroup and communicator for new distribution
! note: MPI_COMM_CREATE must be called by all procs in MPI_COMM_ICE
!
!-----------------------------------------------------------------------
call MPI_GROUP_RANGE_INCL(MPI_GROUP_ICE, 1, range, &
MPI_GROUP_NEW, ierr)
call MPI_COMM_CREATE (MPI_COMM_ICE, MPI_GROUP_NEW, &
new_comm, ierr)
!-----------------------------------------------------------------------
!EOC
end subroutine create_communicator
!***********************************************************************
end module ice_communicate
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