program alltoall
  implicit none
  include "mpif.h"

  integer ierror, rank, size

  integer nrecvd, sum, i, index
  logical flag
  integer, dimension(MPI_STATUS_SIZE) :: send_status, recv_status
  integer request(0:9), in(0:9)
  
  call MPI_Init(ierror)
  
  call MPI_Comm_rank(MPI_COMM_WORLD, rank, ierror)
  call MPI_Comm_size(MPI_COMM_WORLD, size, ierror)
  
  
  do i = 0, size-1
    
     call MPI_Isend(rank+i, 1, MPI_INTEGER, i, 7, MPI_COMM_WORLD, &
                   request(i), ierror)
  enddo
    
  do i = 0, size-1
  
     call MPI_Recv(in(i), 1, MPI_INTEGER, i, 7, MPI_COMM_WORLD, &
                   recv_status, ierror)
  enddo
    
  nrecvd = 0
  do while( nrecvd < size)
     flag = .false.
     call MPI_Testany(size, request, index, flag, send_status, ierror)
     
     if(flag) then
        nrecvd = nrecvd+1
        write(*,'( i2," finished sending to "i2)') rank, index
     else
        write(*,'(i2," waiting ...")') rank
     endif
  enddo
  
  
  write(*, '("PE",i1,": in = ",10i4)') rank, in(0:size-1)
  
  call MPI_Finalize(ierror)

  stop
end program alltoall