dolfin team mailing list archive

["Martin Sandve Alnæs" <martinal@xxxxxxxxx>]

2008/6/30 Anders Logg <logg@xxxxxxxxx>:
> On Mon, Jun 30, 2008 at 12:50:39PM +0200, Martin Sandve Alnæs wrote:
>> 2008/6/28 Anders Logg <logg@xxxxxxxxx>:
>> > On Sat, Jun 28, 2008 at 08:55:44PM +0200, Johan Hake wrote:
>> >> Hello!
>> >>
>> >> I tried to compile an advection diffusion form using Streamline Upwind Petrow
>> >> Galerkin stabilazing method, similar to the one introduced in DOLFIN 0.6.4.
>> >> Using 3 dimensional and first degree Lagrange elements, FFC/g++ chokes when
>> >> the produced code is compiling. It wont finish compile... Is this a known
>> >> problem and a limitation of FFC/g++?
>> >
>> > Try compiling with the -r quadrature option. I guess this is not
>> > supported in the JIT compiler yet, but could easily be added. There
>> > should be an option
>> >
>> >  dolfin_set("form representation", "quadrature");
>> >
>> > in the same way as there is an option "optimize". See if you can
>> > figure it out and send a patch, or else file a bug report.
>> >
>> > Options are added in DefaultParameters.h in DOLFIN and the JIT
>> > compiler is in jit.py in FFC.
>> >
>> > Possible options for "form representation" are "tensor", "quadrature"
>> > and (unsupported at the moment) "symbolic" (for SyFi).
>> >
>> > The quadrature representation generates much less code than the tensor
>> > representation.
>>
>> SFC also does quadrature (in fact most users (me) mainly use that),
>> and there are many possible compilation options. I don't think it's a good
>> idea to mix form compiler details into dolfin. We should talk about this
>> to find a solution that doesn't discriminate form compilers :-)
>
> I think we need have to. It is DOLFIN that sends the form to the form
> compiler so DOLFIN needs to make a choice which form compiler to use.
>
> But I agree we should not discriminate form compilers. Any form
> compiler that handles UFL/UFC should be possible to use.

Then we should at least have an options system that doesn't
need every possible form compiler option pre-registered.

And setting form compiler options globally for all jit calls may not
be enough, different forms may call for different compilation options.

As I see it, dolfin doesn't need to know more than the option "form compiler".
Compiler-specific options should be applied to the particular compiler.

Like:
dolfin_set("form compiler", "ffc")
ffc_set("form representation", "quadrature")
A = assemble(ufl_form, ...)

or:
dolfin_set("form compiler", "sfc")
A = assemble(ufl_form, ..., options=sfc_options_dict)

--
Martin