dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Johan Hoffman wrote:
> > Johan Hoffman wrote:
> > > Hi all,
> > >
> > > Connected to this discussion is also the msc thesis work on dolfin
> > > parallization of Nicklas Jansson at KTH. He has now started working on
> > > this based on the updated TODO list of dolfin. He has tried to send an
> > > email to this list (dolfin-dev@xxxxxxxxxx) but it appears that it is
> > > stuck
> > > in a filter awaiting moderator approval.
> > If he joins the list, he'll be able to make posts.
>
> Ok.
>
> > Maybe someone (a moderator) could
> > > help out so that we can get past this, to better coordinate
> > > parallelization efforts?
> > One point on the TODO list: we discussed some time ago the mesh
> > partitioning, and decided against ParMETIS or METIS because they do not
> > use a GPL (compatible) license. Magnus has implemented a nice
> > partitioning interface which uses SOCTCH which does have a GPL
> > compatible license.
>
> Ok. Does the switch to LGPL licence for dolfin make any difference? Or is
> it still a conflict?

There is still a conflict. The METIS license basically says that it can 
be used for non-profit purposes only, and permission is required to 
re-distribute it.

> About Scotch; the argument was that it lacked parallel partitioning, and a
> few other nice features of parMetis. But it seems that Scotch v5.0 is
> moving towards a parallel implementation as well?

It does have it now. That said, I can't see us using or needing parallel 
partitioning in the short- to medium-term future.

Garth

> Also, it appears that Scotch is designed to mimic Metis to allow for a
> common implementation of the two, in particular in v5.0 there seems to be
> such a compatibility library. So maybe the differences are very mild. If
> Scotch does not have what we need for parallel partitioning today, we
> could use parMetis until it does, or at least allow for this option, since
> the implementation should not change much (if at all).
>
> /Johan
>
> > Garth
> >
> > > Thanks!
> > >
> > > /Johan
> > >
> > >
> > > > Anders Logg wrote:
> > > > > On Sat, Dec 01, 2007 at 05:02:13PM +0000, Garth N. Wells wrote:
> > > > > > Looks like you forgot to add MPIManager to the repository.
> > > > > >
> > > > > > Do we want a class MPIManager, or should we let PETSc take of this?
> > > > > > If
> > > > > > we
> > > > > > create an MPI object ourselves, it will probably clash with PETSc.
> > > > > We need it if we sometimes want to use MPI without PETSc (which is not
> > > > > unlikely even if PETSc is the default).
> > > > >
> > > > > MPIManager works like PETScManager and takes care of the global
> > > > > initialization at startup:
> > > > >
> > > > >   MPIManager::init();
> > > > >
> > > > > and also calls finalize() automatically when the program exits. It
> > > > > talks to MPI to see if it has already been initialized (by PETSc,
> > > > > itself or someone else) and does nothing if that is the case.
> > > > OK.
> > > >
> > > > Garth
> > > > _______________________________________________
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> > > > DOLFIN-dev@xxxxxxxxxx
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