It's harmless. You could check the size of the communicator if you wanted
to be more correct, or rename the variable to something more accurate.

On Wednesday, May 28, 2014, David Ketcheson <notifications@github.com>
wrote:

> In src/pyclaw/util.py:
>
> > @@ -26,6 +31,55 @@ def add_parent_doc(parent):
> >      ==========================
> >      """ + parent.__doc__
> >
> > +def run_serialized(fun):
> > +    """ Decorates a function to only run serially, even if called in parallel.
> > +
> > +    In a parallel communicator, the first process will run while the remaining processes
> > +    block on a barrier.  In a serial run, the function will be called directly.
> > +
> > +    This currently assumes the global communicator is PETSc.COMM_WORLD, but is easily
> > +    generalized.
> > +    """
> > +
> > +    try:
> > +        from petsc4py import PETSc
> > +        is_parallel = True
>
> Just because petsc4py is installed on a system doesn't mean the function
> is being executed in parallel. But I can't find a situation in which this
> actually breaks something. Do you think it is harmless?
>
> —
> Reply to this email directly or view it on GitHub<https://github.com/clawpack/pyclaw/pull/398/files#r13117270>
> .
>