On Sep 13, 2012, at 7:55 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> On Thu, Sep 13, 2012 at 8:50 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
> On Sep 12, 2012, at 9:49 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
>
> > This patch seems to do two very unrelated things. More importantly, it
> > makes libpetscmat depend on libpetscksp, thus breaking single-library=0.
> > The register routine needs to be moved to src/ksp to fix this.
>
> Yup. My mistake.
>
> I don't like the idea of shoving it directly in KSPRegisterAll().
> Instead what about KSPMatRegisterAll() that is called, like KSPRegisterAll()
> by KSPInitializePackage()
>
> Similarly you would have SNESKSPRegisterAll() for your KSPPOLY.
>
> Fine, so SNESInitializePackage() would call SNESKSPRegisterAll() and the user
> should call one or the other if they don't use SNES but want to use those KSP
> implementations.
>
> Bear in mind that it'll work automatically with dynamic libraries since the
> package is initialized when the shared lib is loaded. Now should we also use
> the constructor trick to let the user skip this on all systems supporting the
> attribute (most).
I don't really care, it is fine with me if you want to do this.
Barry
>
>
> Barry
>
> Note also the manual page for MatRegisterAll() should have a reference to
> KSPMatRegisterAll().
>
>
> >
> > In principle, I'd be fine with putting it in KSPRegisterAll. Instead of
> > thinking of that routine as "register all implementations of KSP" (which it
> > never truly meant), I think of it as "register all implementations of
> > anything provided by the KSP package". The downside of that is that
> > MatCreate calls MatInitializePackage, but does not call
> > KSPInitializePackage, causing MatSetType(S,MATSCHURCOMPLEMENT) to fail when
> > !defined(PETSC_USE_DYNAMIC_LIBRARIES) and KSPInitializePackage() has not
> > been called.
> >
> > Unfortunately, I there isn't a way short of static constructors to
> > initialize only those packages that are linked. With C++, we could have a
> > static constructor that registered itself. With GCC and related compilers,
> > we can use __attribute__((constructor)) to get a routine called before main
> > (it would add the existing XXInitializePackage() to a list that
> > PetscInitialize() would call later). Both of these options run code before
> > main which means we have to be especially careful that it never causes an
> > error because that is very confusing.
> >
> > On systems that don't support constructors, I think the user will have to
> > call KSPInitializePackage themselves if they are going to MatSetType
> > MATSCHURCOMPLEMENT before KSPCreate. I think this particular combination is
> > extremely unlikely, but I have a similar issue with my new KSPPOLY (the
> > implementation needs SNES to solve a constrained minimization problem) and
> > that makes sense to use via -ksp_type poly when the user does not interact
> > with SNES at all.
> >
> > changeset: ec8eb69c0c42
> > user: Barry Smith <bsmith at mcs.anl.gov>
> > date: Thu Aug 23 08:03:00 2012 -0500
> > files: conf/test include/petscksp.h src/ksp/ksp/utils/schurm.c
> > src/mat/interface/matregis.c
> > description:
> > added testexamples_opengl rule
> > changed MatCreateSchurComplement to use the MatCreate_SchurComplement()
> > paradigm
> >
>
>
