| |
| c--------------------------------------------------------------------- |
| c--------------------------------------------------------------------- |
| |
| subroutine exchange_4(g,h,ibeg,ifin1,jbeg,jfin1) |
| |
| c--------------------------------------------------------------------- |
| c--------------------------------------------------------------------- |
| |
| c--------------------------------------------------------------------- |
| c compute the right hand side based on exact solution |
| c--------------------------------------------------------------------- |
| |
| implicit none |
| |
| include 'mpinpb.h' |
| include 'applu.incl' |
| |
| c--------------------------------------------------------------------- |
| c input parameters |
| c--------------------------------------------------------------------- |
| double precision g(0:isiz2+1,0:isiz3+1), |
| > h(0:isiz2+1,0:isiz3+1) |
| integer ibeg, ifin1 |
| integer jbeg, jfin1 |
| |
| c--------------------------------------------------------------------- |
| c local variables |
| c--------------------------------------------------------------------- |
| integer i, j |
| integer ny2 |
| double precision dum(1024) |
| |
| integer msgid1, msgid3 |
| integer STATUS(MPI_STATUS_SIZE) |
| integer IERROR |
| |
| |
| |
| ny2 = ny + 2 |
| |
| c--------------------------------------------------------------------- |
| c communicate in the east and west directions |
| c--------------------------------------------------------------------- |
| |
| c--------------------------------------------------------------------- |
| c receive from east |
| c--------------------------------------------------------------------- |
| if (jfin1.eq.ny) then |
| call MPI_IRECV( dum, |
| > 2*nx, |
| > dp_type, |
| > east, |
| > from_e, |
| > MPI_COMM_WORLD, |
| > msgid3, |
| > IERROR ) |
| |
| call MPI_WAIT( msgid3, STATUS, IERROR ) |
| |
| do i = 1,nx |
| g(i,ny+1) = dum(i) |
| h(i,ny+1) = dum(i+nx) |
| end do |
| |
| end if |
| |
| c--------------------------------------------------------------------- |
| c send west |
| c--------------------------------------------------------------------- |
| if (jbeg.eq.1) then |
| do i = 1,nx |
| dum(i) = g(i,1) |
| dum(i+nx) = h(i,1) |
| end do |
| |
| call MPI_SEND( dum, |
| > 2*nx, |
| > dp_type, |
| > west, |
| > from_e, |
| > MPI_COMM_WORLD, |
| > IERROR ) |
| |
| end if |
| |
| c--------------------------------------------------------------------- |
| c communicate in the south and north directions |
| c--------------------------------------------------------------------- |
| |
| c--------------------------------------------------------------------- |
| c receive from south |
| c--------------------------------------------------------------------- |
| if (ifin1.eq.nx) then |
| call MPI_IRECV( dum, |
| > 2*ny2, |
| > dp_type, |
| > south, |
| > from_s, |
| > MPI_COMM_WORLD, |
| > msgid1, |
| > IERROR ) |
| |
| call MPI_WAIT( msgid1, STATUS, IERROR ) |
| |
| do j = 0,ny+1 |
| g(nx+1,j) = dum(j+1) |
| h(nx+1,j) = dum(j+ny2+1) |
| end do |
| |
| end if |
| |
| c--------------------------------------------------------------------- |
| c send north |
| c--------------------------------------------------------------------- |
| if (ibeg.eq.1) then |
| do j = 0,ny+1 |
| dum(j+1) = g(1,j) |
| dum(j+ny2+1) = h(1,j) |
| end do |
| |
| call MPI_SEND( dum, |
| > 2*ny2, |
| > dp_type, |
| > north, |
| > from_s, |
| > MPI_COMM_WORLD, |
| > IERROR ) |
| |
| end if |
| |
| return |
| end |
