GULP

GULP is a program for performing a variety of types of simulation on materials using boundary conditions of 0-D (molecules and clusters), 1-D (polymers), 2-D (surfaces, slabs and grain boundaries), or 3-D (periodic solids).

Software Location

The software is located on the system in the following location:

/apps/gulp

Compilation on 64-bit Systems with Intel compiler

When I tried to compile the GULP software on the cluster, the

compilation went quite smoothly (with the exception of a couple of extra
characters in format specifications in a couple of files... they are
ignored by the fortran compiler, but it would be nice if those were
cleaned up sometime so that the compile is truly clean... I have diffs
of the four files that have this problem if you want).

The problem came about with execution of the software, which failed
miserably with the following error:

 forrtl: error (69): process interrupted (SIGINT)

I then proceeded to compile the software with debug enabled (by the way,
doing a make gulp_debug appears to be broken) and ran it through the
debugger. The line it was breaking on each time seemed very innocent:

 (channels.F:L103)
        if (nunit.lt.0) nunit = - nunit

In a comment above this you mention that taking abs(nunit) crashes on a
DEC. Well, this appears to crash on x86_64. I never tried using
abs(nunit) as I figured the code you had should just work, so I thought
that something else must be wrong.

That was when I started messing with optimization levels of the code. I
first turned optimization off completely, and the code worked fine with
test input. I then started ramping up the optimizations only to find
that optimization of any level on the standard files would break the
program at this point.

As it stands now, the optimizations I currently have in the file
getmachine are as follow:

# Intel compiler
                 echo 'OPT=-O0 -mp1 ' > makefile
                 echo 'OPT1=-O1 ' >> makefile

I then thought to myself that there must be a way to get better
optimization than this, so I specifically singled out channels.F and
reduced the optimization on that particular file to nothing, while
leaving the rest at -O3. This just propagated the fault to a new file.
It was at this point I gave up as I don't have the time to chase this
down through all of the different files, so leaving a good portion of
the code un-optimized is my current option.