Newsgroups: comp.parallel.pvm,comp.parallel.mpi
From: jsquyres@lsc.nd.edu (Jeff Squyres)
Subject: Re: Passing C++ objects
Organization: University of Notre Dame
Date: 29 Feb 1996 00:53:54 GMT
Message-ID: <4h2tf2$87c@news.nd.edu>

: The examples for passing data between processes have shown how it is 
: possible to pass variables and arrays of specific types.  How is this 
: accomplished when you need to send a object, containing several data types 
: of which some may be dynamically allocated,  to another process. 

: The worst case could be that the object needs the functionallity to send 
: and recieve its variable/array components such that it could reconstruct 
: itself.

Ah ha!  An opprotunity for the shameless plug for OOMPI!

Object Oriented MPI (OOMPI) will provide some of these capabilities --
it allows you to build MPI datatypes for objects and then send and
receive those objects.  But OOMPI only allows you send the *data*, not
methods.  Therefore, dynamic allocation is not really possible.  

The reason for this is that OOMPI subscribes to the "MPI Way" of building
a datatype (composed of offsets, etc.) and then ultimately doing an
MPI_Send()/whatever with that datatype.  Perhaps future versions of 
OOMPI will allow the sending of methods along with data...

You may wish to examine our design document; although this document is
extremely out of date by now, the main ideas in the first half of the
document are still mostly true.  The OOMPI WWW page is:

	http://www.cse.nd.edu/~lsc/research/oompi/

OOMPI 1.0.1 is due to be released tomorrow (29 Feb).  It is a lightweight 
layer that is implemented on top of existing MPI (C) libraries.  OOMPI is
not meant to be interpreted as an attempt at C++ bindings for MPI; it is 
a class library.  Work is progressing in a different direction for the C++
bindings in MPI-2.  When MPI-2 is completed, OOMPI will be implemented on 
top of the C++ bindings as well.

OOMPI 1.0.1 will formally be announced at POOMA '96 on Friday, March 1.
See http://www.acl.lanl.gov/Pooma96/ for details, including an abstract
on OOMPI.

However, Notre Dame has a major power outage scheduled tomorrow, and we 
may not be able to finish all the details in time, so please bear with 
us if we are a little late.  :-)

{+} Jeff Squyres
{+} squyres@cse.nd.edu
{+} Perpetual Obsessive Notre Dame Student Craving Utter Madness.  
{+} (*6* years and counting -- 1 more year of eligibility)

