Sorry for those mistakes. I addressed all the three problems
- I put "implicit none" at the top of main program
- I initialized tag.
- changed MPI_INT to MPI_INTEGER
- "send_length" should be just "send", it was a typo.

But the code is still hanging in sendrecv. The present form is below:

main.f


  program   main

  implicit none 

  include  'mpif.h'

  integer me, np, ierror

  call  MPI_init( ierror )
  call  MPI_comm_rank( mpi_comm_world, me, ierror )
  call  MPI_comm_size( mpi_comm_world, np, ierror )

  call sendrecv(me, np)

  call mpi_finalize( ierror )

  stop
  end

sendrecv.f


  subroutine sendrecv(me, np)

  include 'mpif.h'

  integer np, me, sender, tag
  integer, dimension(mpi_status_size) :: status

  integer, dimension(1) :: recv, send

  if (me.eq.0) then

     do sender = 1, np-1
        call mpi_recv(recv, 1, mpi_integer, sender, tag,
 &           mpi_comm_world, status, ierror)

     end do
  end if

  if ((me.ge.1).and.(me.lt.np)) then
     send(1) = me*12

     call mpi_send(send, 1, mpi_integer, 0, tag,
 &        mpi_comm_world, ierror)
  end if

  return
  end


2013/3/1 Jeff Squyres (jsquyres) <jsquyres@cisco.com>
On Feb 28, 2013, at 9:59 AM, Pradeep Jha <pradeep@ccs.engg.nagoya-u.ac.jp> wrote:

> Is it possible to call the MPI_send and MPI_recv commands inside a subroutine and not the main program?

Yes.

> I have written a minimal program for what I am trying to do. It is compiling fine but it is not working. The program just hangs in the "sendrecv" subroutine. Any ideas how can I do it?

You seem to have several errors in the sendrecv subroutine.  I would strongly encourage you to use "implicit none" to avoid many of these errors.  Here's a few errors I see offhand:

- tag is not initialized
- what's send_length(1)?
- use MPI_INTEGER, not MPI_INT (MPI_INT = C int, MPI_INTEGER = Fortran INTEGER)


> main.f
>
>
>   program   main
>
>   include  'mpif.h'
>
>   integer me, np, ierror
>
>   call  MPI_init( ierror )
>   call  MPI_comm_rank( mpi_comm_world, me, ierror )
>   call  MPI_comm_size( mpi_comm_world, np, ierror )
>
>   call sendrecv(me, np)
>
>   call mpi_finalize( ierror )
>
>   stop
>   end
>
> sendrecv.f
>
>
>   subroutine sendrecv(me, np)
>
>   include 'mpif.h'
>
>   integer np, me, sender
>   integer, dimension(mpi_status_size) :: status
>
>   integer, dimension(1) :: recv, send
>
>   if (me.eq.0) then
>
>      do sender = 1, np-1
>         call mpi_recv(recv, 1, mpi_int, sender, tag,
>  &           mpi_comm_world, status, ierror)
>
>      end do
>   end if
>
>   if ((me.ge.1).and.(
> me.lt.np
> )) then
>      send_length(1) = me*12
>
>      call mpi_send(send, 1, mpi_int, 0, tag,
>  &        mpi_comm_world, ierror)
>   end if
>
>   return
>   end
>
> _______________________________________________
> users mailing list
> users@open-mpi.org
> http://www.open-mpi.org/mailman/listinfo.cgi/users


--
Jeff Squyres
jsquyres@cisco.com
For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/


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