Subject: Re: CCL:Problem with Macromodel on IRIX

From: Bruno Bienfait <[email-masked]>
Date: Fri, 09 Jul 1999 12:59:34 -0400

Peter Shenkin wrote:

> Hi,
>
> There is a bug in the -mips4 fast math library (libfastm.so) originally
> distributed with IRIX 6.4 (and 6.3).  This can be fixed by upgrading to
> IRIX 6.5, or by installing patch Patch 1774 or 3131 & 3219, or 2752. (Some of
> these may superceded;  if so, install the later one(s).  But
> your best bet is to upgrade.
>
> BTW, this is Q4.4 on our FAQ page,
>         http://www.schrodinger.com/MacroModel/faq.html
>
> Hope this helps,
> -P.
>

Thanks a lot for your quick answer.  Thanks also to the two other persons
who replied. I installed the patches 3131 and 3219 on the IRIX 6.4
machine.  Thereafter, the output of the cyclohexane energy calculation was
identical to the one obtained on the IRIX 6.5 machines.  The FAQ page, as
mentioned by Peter, clearly describes this solution.  We are currently
checking the patch versions on all our SGI workstations.

I feel lucky that I used two different SGI workstations for the same
calculation, otherwise I wouldn't have noticed this problem.

Does anyone know what functions in the math library (libfastm.so) were broken
and which other programs may be affected (e.g CHARMM)?

Also, I am looking for a piece of C code that tests the validity of the
library by performing a simple math operation related to the broken
functions.  This code would report an error message and stop the program
if the result is not correct.  One reason that I'm interested in this
(instead of simply applying the patches) is that we run a lot of our
programs on various central SGI systems for which we don't have root
privileges, and on which the patch situation not known to us offhand,
so I want a "hard test" to see if things are alright or not. Another reason is
that I would like to  incorporate such a test into my own programs which are
freely available and might be running by other people on unpatched IRIX machines.

I believe that this buggy fast math library is a much more serious problem
than the "Pentium bug".

Bruno

--
[ Bruno Bienfait, Ph. D.            Laboratory of Medicinal Chemistry ]
[                                   National Cancer Institute         ]
[ Email : [email-masked]      National Institutes of Health     ]
[ Phone : (301) 402-3111            Building 37, Room 5B20            ]
[ Fax   : (301) 496-5839            Bethesda Maryland 20892 , USA     ]
[ WWW   : http://www.brunob.org                                       ]