dolfin team mailing list archive

[Johan Hake <hake.dev@xxxxxxxxx>]

On 11/15/2012 09:59 PM, Martin Sandve Alnæs wrote:
> Definitely a good plan. 1.1 release in december would be nice, then we
> can think more freely in january.

++

Johan

> Martin
> 
> 
> On 15 November 2012 21:35, Marie E. Rognes <meg@xxxxxxxxx
> <mailto:meg@xxxxxxxxx>> wrote:
> 
> 
> 
>     On 15. nov. 2012, at 21:23, Anders Logg <logg@xxxxxxxxx
>     <mailto:logg@xxxxxxxxx>> wrote:
> 
>     > On Thu, Nov 15, 2012 at 10:22:05AM +0100, Johan Hake wrote:
>     >> On 11/15/2012 08:54 AM, Anders Logg wrote:
>     >>> It might be a good thing to move it to la but then we need a new
>     >>> fem/mesh independent abstraction to replace the current DofMap
>     class.
>     >>> Instead of the letting a dolfin::Cell be a central concept, it
>     can be
>     >>> something else corresponding to a cell, a facet, subsets or even
>     >>> groups of mesh entities.
>     >>
>     >> Why would this be necessary?
>     >
>     > To support more general finite element spaces and to simplify the
>     code.
>     >
>     >>> One thing I want to do when we're anyway talking about big
>     changes is
>     >>> to work out a very different design for UFC 3.0 which will get
>     rid of
>     >>> all the copying between ufc::foo and dolfin::Foo classes. We tried
>     >>> really hard to make minimal assumptions in UFC on data structures so
>     >>> the code could be used from other libraries, but as far as I
>     know all
>     >>> other libraries using some part of the toolchain (UFL or form
>     >>> compilers) generate code directly for their own backend anyway,
>     >>> completely bypassing UFC. It was a nice idea, but it looks like the
>     >>> assumption it could be reused has failed.
>     >>
>     >> Now we are talking! I guess several things could go into such a
>     rewrite.
>     >> Maybe fire up a Blueprint?
>     >
>     > Yes, but I'm not sure I would be able to write it up as a
>     > blueprint. Some experiments will be necessary first.
>     >
>     >>> I believe we could make the DofMap class much simpler by improving
>     >>> the code generation to fit better to DOLFIN.
>     >>
>     >> That part might be simpler but with huge cost in refactoring existing
>     >> code...
>     >
>     > Yes, it will cost. But it's 5 years since we designed UFC and the
>     > add-ons on top of it (the DofMap, DofMapBuilder, SparsityPattern,
>     > SparsityPatternBuilder, AssemblerBase classes) are growing more and
>     > more complex and making it hard to maintain and add new
>     > features. Since UFC 1.0, we have also gone parallel so we (mostly
>     > Garth) have quite a bit of experience we didn't have back then.
>     >
>     > I discussed this with Garth and the suggestion is we make the buildbot
>     > happy, fix bugs, get the size_t stuff in place and release 1.1.0. Then
>     > we can take larger steps towards a new design for 2.0.
>     >
> 
> 
>     Sounds like a good plan!
> 
>     --
>     Marie
> 
>     > --
>     > Anders
>     >
>     >
>     >>>> Would it be possible to move DofMaps to dolfin/la and make them
>     backend
>     >>>> specific?
>     >>>>
>     >>>> Johan
>     >>>>
>     >>>> On 11/15/2012 08:16 AM, Garth N. Wells wrote:
>     >>>>> On Thu, Nov 15, 2012 at 6:37 AM, Martin Sandve Alnæs
>     <martinal@xxxxxxxxx <mailto:martinal@xxxxxxxxx>> wrote:
>     >>>>>> ---------- Videresendt melding ----------
>     >>>>>> Fra:
>     >>>>>> Dato: 15. nov. 2012 07:35
>     >>>>>> Emne: Re: [Dolfin] unsigned int -> std::size_t
>     >>>>>> Til: "Garth N. Wells" <gnw20@xxxxxxxxx <mailto:gnw20@xxxxxxxxx>>
>     >>>>>>
>     >>>>>>
>     >>>>>> A typedef for the chosen linear algebra backend? How is that
>     possible with
>     >>>>>> dynamic choice of backend?
>     >>>>>
>     >>>>> A 'primary' backend will need to be decided at configure time,
>     and the
>     >>>>> index type will match the index type of the primary backend. I
>     don't
>     >>>>> see any way to get around this. Templating some functions will not
>     >>>>> help because the dof map needs to use a compatible index type, and
>     >>>>> this would tie a dof map to a backend (and templates will make the
>     >>>>> code more complicated).
>     >>>>>
>     >>>>> At present we just assume that all backends use an index type
>     that is
>     >>>>> compatible with unsigned int, but we can't justify this
>     assumption.
>     >>>>> Flaws in DOLFIN la handling have shown up with the release of
>     Trilinos
>     >>>>> 11, which introduces 64-bit ints to its interface. PETSc uses
>     >>>>> PetscInt, and we have just assumed that it's compatible with
>     unsigned
>     >>>>> int.
>     >>>>>
>     >>>>> Garth
>     >>>>>
>     >>>>>
>     >>>>>> Martin
>     >>>>>>
>     >>>>>> Den 14. nov. 2012 18:06 skrev "Garth N. Wells"
>     <gnw20@xxxxxxxxx <mailto:gnw20@xxxxxxxxx>> følgende:
>     >>>>>>
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