!
!   On src:   m(10,10) 
!             send section m(2:6,4:9)
!
!   On dest   m(12,8)
!             recv section m(7:11,2:7)

program array_sect
  implicit none
  include "mpif.h"
  integer, dimension(:,:), allocatable :: m
  integer :: mx, my, nx, ny
  integer ierror, rank, size
  integer, parameter :: src = 1, dest = 0
  integer section, status(MPI_STATUS_SIZE)
  integer i,j

  call MPI_Init(ierror)
  
  call MPI_Comm_rank(MPI_COMM_WORLD, rank, ierror)
  call MPI_Comm_size(MPI_COMM_WORLD, size, ierror)


  if (rank==src) then
     mx = 10; my = 10
     allocate(m(mx,my))

     write(*,'("Source array:")')
     do j = 1,10
        do i = 1,10
           m(i,j) = (i-1)*10 + j-1
        enddo
        write(*,'(10i4)') m(:,j)
     enddo

     nx = 6-2+1; ny = 9-4+1;  ! m(2:6,4:9)
  else
     mx = 12; my = 8
     allocate(m(mx,my))
     m = 0

     nx = 11-7+1; ny = 7-2+1;  ! m(7:11,2:7)
  endif

  call MPI_Type_Vector(ny, nx, mx, MPI_INTEGER, section, ierror)

  call MPI_Type_Commit(section, ierror)

  
  if (rank==src) then
     call MPI_Send( m(2,4), 1, section, dest, 7, MPI_COMM_WORLD, ierror)
  else
     call MPI_Recv( m(7,2), 1, section, src, 7, &
                         MPI_COMM_WORLD, status, ierror)
     write(*,'("Target array:")')
     do j = 1,7
        write(*,'(12i4)') m(:,j)
     enddo
  end if

  call MPI_Finalize(ierror)

  stop
end program array_sect