[comp.lang.fortran] Floating-point arithmetic and language standardization

Beebe@SCIENCE (Nelson H.F. Beebe) (01/21/88)

Both Fortran and C are currently in the ANSI draft
standardization process, and it is an appropriate time to
reflect on the vagaries of floating-point arithmetic and on
the question of providing decent floating-point support in
programming languages.

The IEEE P754 floating-point standard, now implemented
(though not always completely) in coprocessors from Inmos,
Intel, Motorola, National Semiconductor, Weitek, Western
Digital, and perhaps others, provides a much more
satisfactory model of floating-point arithmetic than has
previously been the case on commercial computers.

David Hough (pronounced "huff") (Arpanet: dgh@sun.com,
Usenet: sun!dhough), one of the designers of IEEE P754, has
been making a careful analysis of draft ANSI C with respect
to floating-point support, and his extended comments have
been evolving over the last few months on the basis of
feedback from net colleagues who review each new draft.  For
a recent contents summary of his work, see the posting of
14-Dec-87 on the NA (numerical analysis) newsgroup
distributed from SCORE.STANFORD.EDU.

Since the topic of Fortran to C convertors pops up
frequently in both the Fortran and C newsgroups, there is
clear evidence that many Fortran users are contemplating, or
are already in progress with, a conversion from Fortran to
C.  It is also significant, I believe, that the trend on
supercomputers is toward Unix operating systems, and to
investigation of the use of facilities, like remote
procedure calls permitting dynamic communication between
workstations and supercomputer, wherein C will play an
increasingly important role in scientific computations.

I therefore feel that it is relevant to bring Hough's work
to the attention of this newsgroup, because many of his
comments APPLY EQUALLY WELL TO FORTRAN.  He will send copies
of his comments to anyone on the net who requests it.

If you feel that the quality of floating-point support in
programming languages is important, I urge you to send for
his comments.
-------

john@nmtsun.nmt.edu (John Shipman) (01/26/88)

In article <12359761762.8.BEEBEX@SCIENCE.UTAH.EDU>, Beebe@SCIENCE
(Nelson H.F. Beebe) writes:
>  ... [most of posting deleted]
> Since the topic of Fortran to C convertors pops up
> frequently in both the Fortran and C newsgroups, there is
> clear evidence that many Fortran users are contemplating, or
> are already in progress with, a conversion from Fortran to
> C....
> [C may] play an
> increasingly important role in scientific computations.
> 
What about type COMPLEX?  Presumably the FORTRAN-to-C translators are
generating calls to library routines to handle COMPLEX calculations.

Questions for you folks in net-land:

1.  Will complex-number users mind writing a lot of function calls,
    instead of just writing expressions as they do now in FORTRAN?

2.  Has the standards committee considered a complex type for C?



-- 
John Shipman/Zoological Data Processing/Socorro, New Mexico
USENET: ihnp4!lanl!unm-la!unmvax!nmtsun!john  CSNET: john@nmt.csnet
  ``If you can't take it, get stronger.'' --Falline Danforth