task_assign_bnd.f90

subroutine task_assign_bnd(f,dimx1,dimx2,dimy1,dimy2,dimz,buff,tag)
	
! this routine assignes the boundary info after MPI exchange

use grid
implicit none
	
integer dimx1, dimx2, dimy1, dimy2, dimz
real f(dimx1:dimx2, dimy1:dimy2, dimz)
	
real buff(*)	! buff for sending data
integer tag

integer i, j, k, n, proc
integer i1, i2, j1, j2

!       The dimensions of the fields in common com3d. Needed by MPI

!       Decode the tag:

i= tag/100000
i1 = (tag-i*100000)/10000
i2 = (tag-i*100000-i1*10000)/1000
j1 = (tag-i*100000-i1*10000-i2*1000)/100
j2 = (tag-i*100000-i1*10000-i2*1000-j1*100)/10
proc =tag-i*100000-i1*10000-i2*1000-j1*100-j2*10
	
! From "North":

	  if    (proc.eq.1) then

	     n=0
	     do k=1,dimz
	       do j=nyp1,nyp1+j2
	         do i=1,nx
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do
	  
! From "North-East":

	  elseif(proc.eq.2) then

	     n=0
	     do k=1,dimz
	       do j=nyp1,nyp1+j2
	         do i=nxp1,nxp1+i2
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do

! From "East":

	  elseif(proc.eq.3) then
	  
	     n=0
	     do k=1,dimz
	       do j=1,ny
	         do i=nxp1,nxp1+i2
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do
	  
! From "South-East":

	  elseif(proc.eq.4) then
	  
	     n=0
	     do k=1,dimz
	       do j=-j1,0
	         do i=nxp1,nxp1+i2
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do
	  
! From "South":

	  elseif(proc.eq.5) then
	  
	     n=0
	     do k=1,dimz
	       do j=-j1,0
	         do i=1,nx
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do
	     
! From "South-West":

	  elseif(proc.eq.6) then
	  
	     n=0
	     do k=1,dimz
	       do j=-j1,0
	         do i=-i1,0
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do
	     
! From "West":

	  elseif(proc.eq.7) then
	  
	     n=0
	     do k=1,dimz
	       do j=1,ny
	         do i=-i1,0
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do
	     	  
! From "North-West":

	  elseif(proc.eq.8) then
	  
	     n=0
	     do k=1,dimz
	       do j=nyp1,nyp1+j2
	         do i=-i1,0
	           n = n+1
	           f(i,j,k) = buff(n)
	         end do
	       end do
	     end do
	     
	  endif
	
	
end