Fortran vs. C for numerical work (SUMMARY)

[John Prentice]

In article <26434:Dec404:42:4990 at kramden.acf.nyu.edu> brnstnd at kramden.acf.nyu.edu (Dan Bernstein) writes:
>One of the great advantages of the classical Fortran numerical libraries
>is that they are so reliable that the code never has to be maintained. A
>library is a library is a library.

I hate to do it, but I have to at least qualify this point. I have a good friend
who is in charge of maintaining the SLATEC and IMSL libraries at the Air
Force Weapons Laboratory (Cray 2, IBM 3070, and a bunch of workstation 
systems).  SLATEC is a joint project by Sandia, Livermore, Los Alamos, and
the Air Force Weapons Laboratory and is a large mathematical library,
somewhat like IMSL but free.  The software there is easily as good as
what I have seen in other libraries like IMSL or NAG.  However, I am
digressing.  His experience with these well worn and tested libraries is
that they quite often will not compile on new machines and will often
fail the quick checks until someone goes in and makes minor changes to the
code.  Now, the changes are usually minor, more often then not it is
just a question of changing some floating point test for small numbers, etc...
However, there have also been cases where the answers are just plain
wrong.  So, on an system where a library has been resident for long
periods, there is a good chance it is reliable (though it is not
an absolute certainty).  However, from what I have seen and heard of
these libraries, they are not easily transported to new systems and
unfortunately in science, new systems are always happening.  Perhaps
someone involved with SLATEC, IMSL, NAG, etc... could comment on all this.

So, I basically agree with Dan's comment, but it is not quite as simple
perhaps as his comment suggests.

John Prentice
Amparo Corporation
john at unmfys.unm.edu