[Petsc-trilinos-discussion] Scope and requirements

[Barry Smith]

On Nov 22, 2013, at 7:41 PM, Bartlett, Roscoe A. <bartlettra at ornl.gov> wrote:

> So what? If it solves a problem, what is it to us what a client application does?

   I think Jed explained this pretty well in his later email.

> The problem is that there should be no link ordering reqiirement between trilinos and petsc.

   We can do this. We build PETSc and then after Trilinos is located (which may be even after the application is linked) we build the ML wrapper.  Yes currently it is terribly documented and foggy, thanks for making that clear. We will simplify the steps to do this and document how one does this. We can do this with many of the external packages but it is currently too obscure.

   Barry



> What if trilinos had adapters for petsc solvers and preconditioners (like was supposed to happen in tops-2 ), how would that work (that is called a circular dependency)? With C++ we could just put in static initialization code in downstream lib to insert adapter automatically but there should really be an independent package outside of both that provides trilinos and petsc interoperability and that solves the ordering problem.
> 
> -Ross
> 
> 
> -----Original Message-----
> From: Barry Smith [bsmith at mcs.anl.gov]
> Sent: Friday, November 22, 2013 08:02 PM Eastern Standard Time
> To: Bartlett, Roscoe A.
> Cc: Jed Brown; Matthew Knepley; petsc-trilinos-discussion at lists.mcs.anl.gov
> Subject: Re: [Petsc-trilinos-discussion] Scope and requirements
> 
> 
> On Nov 22, 2013, at 6:48 PM, Bartlett, Roscoe A. <bartlettra at ornl.gov> wrote:
> 
> > Then what is the issue with shared vs static libs? Why can't downstream client app just compile the petsc ml adapter, call the registration func then use ml under petsc like before?
> 
>    They can. Our objection to this is
> 
> > call the registration func.
> 
>     Barry
> 
> 
> >
> > -Ross
> >
> > -----Original Message-----
> > From: Jed Brown [jedbrown at mcs.anl.gov]
> > Sent: Friday, November 22, 2013 06:44 PM Eastern Standard Time
> > To: Matthew Knepley; Bartlett, Roscoe A.
> > Cc: Barry Smith; petsc-trilinos-discussion at lists.mcs.anl.gov
> > Subject: Re: [Petsc-trilinos-discussion] Scope and requirements
> >
> > Matthew Knepley <knepley at gmail.com> writes:
> >
> > > http://en.wikipedia.org/wiki/Dependency_injection Yes, we use plugins in
> >
> > > exactly the same way. They obey the top-level interface,
> >
> > > just like your Stratimikos interfaces, and we instantiate the concrete type
> >
> > > dynamically (we can load the appropriate DLL with a
> >
> > > runtime option if necessary). It has been this way since I was in grad
> >
> > > school in 1996.
> >
> >
> >
> > PETSc's system is closer to what Martin Fowler refers to as "service
> >
> > locator" in his essay which seems to be a popular reference, though the
> >
> > techniques had been around for decades by the time he wrote the essay.
> >
> >
> >
> > http://www.martinfowler.com/articles/injection.html
> >
> 
>