Newsgroups: comp.parallel.mpi
From: Joerg Stiller <stiller@ism.mw.tu-dresden.de>
Subject: understanding requests
Organization: TU Dresden
Date: Mon, 06 Jul 1998 18:11:12 +0200
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-ID: <35A0F720.37175FBA@ism.mw.tu-dresden.de>

Hi,

I am a bit confused about how to use "requests" correctly.
Please consider the following example:

  call MPI_IRECV(buf1, count1, datatype1, source, tag, comm, request,
..)
  call MPI_REQUEST_FREE(request, ..)
  call MPI_IRECV(buf2, count2, datatype2, source, tag, comm, request,
..)
  call MPI_WAIT(request, status, ..)

(1) Is this legal?
(2) Can I reuse a "request" variable immediatly after MPI_REQUEST_FREE?
(3) Can I rely on checking only the last request emerging from a series
    of MPI_ISEND or MPI_IRECV with same source/tag/comm?
(4) Have I to free each request explicitly using MPI_REQUEST_FREE,
    MPI_WAIT, MPI_TEST etc?

Could anyone help me answer these questions, please?

Joerg

--
Joerg Stiller
ADR: TU Dresden, Institut fuer Stroemungsmechanik, D-01062
TEL: ++49 351 4893
FAX: ++49 351 5246
ELM: j.stiller@ism.tu-dresden.de
WWW: http://rcswww.urz.tu-dresden.de/~jstiller