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From: gelato@oort.ap.sissa.it (Sergio Gelato)
Subject: Re: Object-oriented Fortran vs. Ada 95?
Date: 1996/02/21
Message-ID: <4gf445$gn1@ictpsp10.ictp.trieste.it>#1/1
X-Deja-AN: 140461987
references: <DMpy3E.6Lr@csc.liv.ac.uk> <4gajp4$6aj@fg70.rz.uni-karlsruhe.de>
 <w3l4tsmaq9k.fsf@wind.hpc.pko.dec.com> <312A5D68.1B7C@escmail.orl.mmc.com>
organization: SISSA, Trieste
newsgroups: comp.lang.fortran,comp.lang.ada
Date: 1996-02-21T00:00:00+00:00
List-Id: <comp.lang.ada>

In article <312A5D68.1B7C@escmail.orl.mmc.com>,
Ted Dennison  <dennison@escmail.orl.mmc.com> wrote:
>Israel Gale wrote:

>> In article <4gajp4$6aj@fg70.rz.uni-karlsruhe.de>
>> ig25@fg70.rz.uni-karlsruhe.de (Thomas Koenig) writes:

>> >  If you compare Fortran 95 with Ada 95, what obstacles to high
>> >  performance do you see in Ada?

>> Fortran 95 fits naturally with HPF (High Performance Fortran), a set of
>> industry-standard extensions to enable execution in parallel across a
>> network.  Some Fortran 90/95 compilers already come with HPF.  Does Ada
>> have a standard parallel dialect?

>Yup. The OLD version of Ada has tasking primitives not as a dialect, 
>but as an integeral part of the language standard. The new version not
>only has tasking, but optional support (in one of the standard's
>annexes) for distributed programming.

That is very useful for explicit parallelism; but one of the points of
having HPF is precisely to relieve the user from having to specify in
too much detail exactly how the application is to be parallelized.
After all, what is optimal on one system may not be on another.

I'm not saying that Ada compilers cannot be taught the same tricks that
HPF tools use; but will there be a large enough market to entice HPF
developers to apply their technology to Ada as well as Fortran? The
supercomputing center I am using does not currently offer the option of
compiling Ada programs at all; by contrast, they have a rather wide choice
of HPF tools. That won't change unless a significant number of those
scientists and engineers who now use Fortran suddenly decide to learn
Ada; and the overwhelming majority have better things to do with their time,
or think they do. Nothing intrinsically wrong about the design of Ada,
a language I'd personally like to see in more widespread use; but inertia
alone is enough to ensure that Fortran will remain the language of choice
in this particular niche for some time to come.

This thread, however, was motivated by the question whether it is appropriate
to add full-fledged Object-Oriented features to Fortran. Unless there is a
clear need for OOP in conjunction with the kind of features HPF provides,
one can still argue "use Ada if you need OOP, Fortran if you need automatic
parallelism on good old arrays".

Speaking of Annex E to the Ada 95 standard (distributed processing):
is there a free/inexpensive implementation of that annex that will
work---reasonably efficiently, of course---with GNAT on an IBM SP2? 
I was depressed to see all those
  begin
    null;
  end;
in the body of the relevant package (s-rpc.adb) in the GNAT distribution...
Pointers to a more useful replacement will be gratefully received.
-- 
Sergio Gelato