[Wrf-users] WRFV2.0.3.1 and IFORT 8.1 on an 32-bit i686 (not xeon)

[Don Morton]

On Wed, 9 Feb 2005 03:45:56 -0500, "Anthony Toigo"
<toigo at astro.cornell.edu> said:


> completion with no errors.  The problem comes with running wrf.exe.  The
> code always crashes with a SEGV (segmentation violation) in solve_em.
> The exact line (according to the debuggers) is:
> 
> 1080  history_outname = grid%history_outname
> 
> This same error occurs in the exact same place no matter whether I use
> gcc
> or icc, so at least I've ruled that out.
> 
> Adding a debug print line, like
> 
> write(0,*) 'history_outname=',history_outname
> 
> before the Registry-generated assignment statements also causes the code
> to
> crash.  I can't understand why the character*256 variable, or using it in
> an assignment statement, or even just printing it, would cause a
> segmentation violation, but I would like to know.

This doesn't really help solve the problem, and perhaps just adds
"noise"
to the situation, but my experience in the sort of problem described
by Anthony is that these SEGV problems are very often a result of
problems in memory allocation (e.g. exceeding memory bounds somewhere),
and very often the root of the problem is not in the place where the
program is crashing.  Look at it this way - if you have a memory overrun
in the solver, the values might be overwriting variables which simply
have the misfortune of being allocated next to the array that's being
"overrun."  

I claim to know nothing of the structure of WRF code (though I need to),
and simply offer this to help folks avoid spending too much time on
one or two statements that "maybe" aren't the real culprit.  Hell,
I spend my life trying to get students out of these pickles :)

Best,

Don Morton
--
**************************************************************
   Don Morton                      http://www.cs.umt.edu/~morton/
   Department of Computer Science       The University of Montana
   Missoula, MT 59812 | Voice (406) 243-4975 | Fax (406) 243-5139

May your trails be crooked, winding, lonesome, dangerous, leading to the
most amazing view. May your mountains rise into and above the clouds.
-Edward Abbey, naturalist and author (1927-1989)