Recent CACM "viewpoint" article

Recent CACM "viewpoint" article

[Bill Wolfe]

 In the April 1990 issue of _Communications of the ACM_, the
 "viewpoint" section contains an article from Geoffrey Hunter
 of the York University Chemistry Department, which contends
 (in response to major flaws in the Fortran-8x proposal):

   "...Fortran-77 should be retained as the *last* ANSI/ISO
    Standard dialect, and its deficiencies should be remedied
    by selection of an established block-structured language
    (probably Ada, possibly Algol-68) as an alternative to
    Fortran-8x.  Fortran programmers should be advised to
    switch to this alternative language for their future
    programming projects.  Translation of existing programs
    should be automated with a Fortran-77 to Ada/Algol-68
    pre-processor."

  Clearly there is some lack of understanding here as to the
  general advisability of opting for automatic translation, and
  the important alternate strategy of applying pragma Interface
  has been overlooked.  But the response by David Bailey of the
  NASA Ames Research Center at Moffett Field is even worse:

   "I simply do not believe that it is realistic to hope that
    serious Fortran application programs could be automatically
    translated to Ada or Algol-68."

   This will certainly come as a surprise to the companies and
   projects which have done exactly this on a fairly large scale, 
   to Richard Waychoff (who has implemented the Fortran-to-Ada
   translator which is available in the Ada Software Repository),
   and to companies such as Lexeme which are in the business of
   providing automatic Fortran-to-Ada translation services!!  Bailey 
   continues:

    "We in the large-scale scientific computation community are
     now moving ahead very seriously with plans to use the highly
     parallel teraflops-class systems that will be available before
     the year 2000.   In a fairly wide range of applications that
     we wish to map to these systems, the central time-intensive
     computations can be expressed easily as array operations. 
     This class of computations certainly includes the large-grid
     PDE codes that are the mainstay of centers such as ours.  The
     array constructs of the proposed Fortran standard are perfectly
     suited for this type of computation.  They represent the first
     serious step to prividing standard parallel programming constructs
     that can be efficiently supported across a variety of parallel
     systems, including both SIMD and MIMD designs."

   Is there anyone in NUMWG or 9XWG who'd like to take on this issue? 

    "Hunter summarizes by saying "the only technically rational way
     of advancing the art of scientific and engineering programming
     is to abandon Fortran in favor of a modern block-structured
     language such as Algol-68 or Ada."  This suggestion will simply
     not be taken seriously by the heavy-duty scientific computation
     community.  These users simply cannot walk away from large
     application programs with 100,000+ lines of code.  Also, this
     suggestion will not be taken seriously by those of us who are
     exploring highly parallel scientific computation, since at
     present, there is no prospect of standardizing array computation
     constructs in any major language except Fortran-8x."

   Again, the applicability of pragma Interface has been overlooked!

   Such inaccurate or incomplete information on Ada, *especially* in 
   a publication like CACM, needs to be straightened out very quickly;
   I hope that in addition to any discussion that might take place
   here in comp.lang.ada, someone from the SEI will write to CACM to 
   straighten out these two regarding the feasibility (yes) and the
   general advisability (no) of automatic Fortran-to-Ada translation, 
   as well as the alternative strategy of using pragma Interface, and 
   that someone from NUMWG, 9XWG, or both will write CACM regarding 
   the other technical points raised by Bailey.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Recent CACM "viewpoint" article

[Kurt Hirchert]

In fairness to Bailey, I would note

o Saying that some people have found the results of automatic translation
  to be acceptable is quite different from saying the automatic translation
  of Fortran programs is good enough to impose on the entire Fortran
  community.

o Citing services such as Lexeme's ignores the fact that the use of their
  service is not economically realistic for much of the Fortran community.

o Automatically translated programs won't necessarily produce an acceptable
  level of performance.  (Fortran's inbuilt restictions to allow high
  performance are hard to mimic in a language which doesn't have them.
  Certainly an Ada processor could have pragmas to assert similar
  restrictions, but I am not aware of any that have such pragmas today.)

I'm not saying you shouldn't respond to Bailey's comments, but try to avoid
looking like language bigots or reactionaries.
-- 
Kurt W. Hirchert     hirchert@ncsa.uiuc.edu
National Center for Supercomputing Applications

Re: Recent CACM "viewpoint" article

[Jerry Callen]

In article <1990Apr11.190324.27161@ux1.cso.uiuc.edu> hirchert@ux1.cso.uiuc.edu (Kurt Hirchert) writes:
>In fairness to Bailey, I would note
>
>o Saying that some people have found the results of automatic translation
>  to be acceptable is quite different from saying the automatic translation
>  of Fortran programs is good enough to impose on the entire Fortran
>  community.

I'll say, and I'm not even a "Fortran person." See below.

> [stuff deleted]
>
>o Automatically translated programs won't necessarily produce an acceptable
>  level of performance.  (Fortran's inbuilt restictions to allow high
>  performance are hard to mimic in a language which doesn't have them.

I recently worked on an Ada
"benchmark" that was obviously a Fortran program that had been machine
translated to Ada. Fortran statement numbers were changed to labels that
looked like <<L005>>, looping constructs were converted to if tests and
gotos and in general the code was real garbage. The labels and gotos will
cause any reasonable optimizer to have fits and give up. Unless an automatic
translation system can do a MUCH better job, it's useless. I can't IMAGINE
trying to maintain this sort of crap.

>I'm not saying you shouldn't respond to Bailey's comments, but try to avoid
>looking like language bigots or reactionaries.

I don't have a strong opinion regarding Fortran 8X (or 90, or whatever it
ends up being called). I do have a good friend who's been very heavily
involved with X3J3 and he has expressed occasional disgust with the whole
process; it IS at least somewhat political, and even he isn't completely
convinced that updating Fortran is a great idea. Geez, can't ANY programming
language be allowed to die in its sleep of old age? :-)

In any case, I can't think of any good reason to translate perfectly 
functional code to Ada or Modula or Algol 68 (Algol 68?!? Get real...);
leave it in Fortran, and use pragma interface if you need to access
it from Ada. It certainly makes sense to use a more recent language for
NEW code, though, IF a compiler with suitable performance is available.

>Kurt W. Hirchert     hirchert@ncsa.uiuc.edu
>National Center for Supercomputing Applications

-- Jerry Callen
   jcallen@encore.com

   Speaking from, but certainly not for, Encore Computer Corporation.