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! Send to NW
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1)-stepsize,p_horiz(2)/), &
dest_rank, &
ierr)
send_tag = 1
call mpi_send(a%s(0,1,1),1,interior(level,m),dest_rank,send_tag,MPI_COMM_HORIZ,ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Collect: send from SW failed in mpi_send().")
#endif
end if
if ( corner_se ) then
! send to NW
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1)-stepsize,p_horiz(2)-stepsize/), &
dest_rank, &
ierr)
send_tag = 2
call mpi_send(a%s(0,1,1),1,interior(level,m),dest_rank,send_tag,MPI_COMM_HORIZ,ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Collect: send from SE failed in mpi_send().")
#endif
end if
end if
call finish_timer(t_collect(m))
end subroutine collect
!==================================================================
! Distribute data in a(level,m-1) and store in b(level,m)
!
! Example for p-m = 1, i.e. stepsize = 2:
!
! NW (0,0) --> NE (2,0)
!
! ! .
! v .
! .
! SW (0,2) SE (2,2) [receive from to 0,0]
!==================================================================
subroutine distribute(level,m, & ! multigrid and processor level
a, & ! IN: Data on level (level,m-1)
b) ! OUT: Data on level (level,m)
implicit none
integer, intent(in) :: level
integer, intent(in) :: m
type(scalar3d), intent(in) :: a
type(scalar3d), intent(inout) :: b
integer :: a_n, b_n ! horizontal grid sizes
integer :: nz ! vertical grid size
integer, dimension(2) :: p_horiz
integer :: stepsize
integer :: ierr, source_rank, dest_rank, send_tag, recv_tag, rank, iz
integer :: stat(MPI_STATUS_SIZE)
integer :: send_request(3)
logical :: corner_nw, corner_ne, corner_sw, corner_se
call start_timer(t_distribute(m))
stepsize = 2**(pproc-m)
a_n = a%ix_max-a%ix_min+1
b_n = b%ix_max-b%ix_min+1
nz = a%grid_param%nz
! Work out rank, only execute on relevant processes
call mpi_comm_rank(MPI_COMM_HORIZ, rank, ierr)
call mpi_cart_coords(MPI_COMM_HORIZ,rank,dim_horiz,p_horiz,ierr)
! Ignore all processes that do not participate at this level
if ( (stepsize .eq. 1) .or. ((mod(p_horiz(1),stepsize) == 0) .and. (mod(p_horiz(2),stepsize)) == 0)) then
! Work out coordinates in local 2 x 2 block
if (stepsize .eq. 1) then
corner_nw = ((mod(p_horiz(1),2) == 0) .and. (mod(p_horiz(2),2) == 0))
corner_ne = ((mod(p_horiz(1),2) == 0) .and. (mod(p_horiz(2),2) == 1))
corner_sw = ((mod(p_horiz(1),2) == 1) .and. (mod(p_horiz(2),2) == 0))
corner_se = ((mod(p_horiz(1),2) == 1) .and. (mod(p_horiz(2),2) == 1))
else
corner_nw = ((mod(p_horiz(1)/stepsize,2) == 0) .and. (mod(p_horiz(2)/stepsize,2) == 0))
corner_ne = ((mod(p_horiz(1)/stepsize,2) == 0) .and. (mod(p_horiz(2)/stepsize,2) == 1))
corner_sw = ((mod(p_horiz(1)/stepsize,2) == 1) .and. (mod(p_horiz(2)/stepsize,2) == 0))
corner_se = ((mod(p_horiz(1)/stepsize,2) == 1) .and. (mod(p_horiz(2)/stepsize,2) == 1))
end if
if ( corner_nw ) then
! (Asynchronous) send to NE
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1),p_horiz(2)+stepsize/), &
dest_rank, &
ierr)
send_tag = 0
call mpi_isend(a%s(0,1,a_n/2+1), 1,sub_interior(level,m-1),dest_rank, send_tag, &
MPI_COMM_HORIZ,send_request(1),ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Distribute: send to NE failed in mpi_isend().")
#endif
! (Asynchronous) send to SW
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1)+stepsize,p_horiz(2)/), &
dest_rank, &
ierr)
send_tag = 1
call mpi_isend(a%s(0,a_n/2+1,1),1,sub_interior(level,m-1), dest_rank, send_tag, &
MPI_COMM_HORIZ, send_request(2), ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Distribute: send to SW failed in mpi_isend().")
#endif
! (Asynchronous) send to SE
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1)+stepsize,p_horiz(2)+stepsize/), &
dest_rank, &
ierr)
send_tag = 2
call mpi_isend(a%s(0,a_n/2+1,a_n/2+1),1,sub_interior(level,m-1), dest_rank, send_tag, &
MPI_COMM_HORIZ, send_request(3), ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Distribute: send to SE failed in mpi_isend().")
#endif
! While sending, copy local data
do iz=0,nz+1
b%s(iz,1:b_n,1:b_n) = a%s(iz,1:b_n,1:b_n)
end do
! Only proceed when async sends to complete
call mpi_waitall(3, send_request, MPI_STATUSES_IGNORE, ierr)
end if
if ( corner_ne ) then
! Receive from NW
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1),p_horiz(2)-stepsize/), &
source_rank, &
ierr)
recv_tag = 0
call mpi_recv(b%s(0,1,1),1,interior(level,m),source_rank,recv_tag,MPI_COMM_HORIZ,stat,ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Distribute: receive on NE failed in mpi_recv().")
#endif
end if
if ( corner_sw ) then
! Receive from NW
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1)-stepsize,p_horiz(2)/), &
source_rank, &
ierr)
recv_tag = 1
call mpi_recv(b%s(0,1,1),1,interior(level,m),source_rank,recv_tag,MPI_COMM_HORIZ,stat,ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Distribute: receive on SW failed in mpi_recv().")
#endif
end if
if ( corner_se ) then
! Receive from NW
call mpi_cart_rank(MPI_COMM_HORIZ, &
(/p_horiz(1)-stepsize,p_horiz(2)-stepsize/), &
source_rank, &
ierr)
recv_tag = 2
call mpi_recv(b%s(0,1,1),1,interior(level,m),source_rank,recv_tag,MPI_COMM_HORIZ,stat,ierr)
#ifndef NDEBUG
if (ierr .ne. 0) &
call fatalerror("Distribute: receive on NW failed in mpi_recv().")
#endif
end if
end if
call finish_timer(t_distribute(m))
end subroutine distribute
end module communication