ffc team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Wed, Dec 09, 2009 at 08:25:24AM -0800, Johan Hake wrote:
> On Wednesday 09 December 2009 08:13:20 Anders Logg wrote:
> > On Wed, Dec 09, 2009 at 08:04:48AM -0800, Johan Hake wrote:
> > > On Wednesday 09 December 2009 01:59:58 Anders Logg wrote:
> > > > On Tue, Dec 08, 2009 at 11:52:38PM -0800, Johan Hake wrote:
> > > > > On Tuesday 08 December 2009 17:09:09 Anders Logg wrote:
> > > > > > We're working on simplifying the FFC code (and parts of UFL). Both
> > > > > > have grown out of hand and with limited resources (like Martin and
> > > > > > Johan leaving for other ventures) we need to make the codebase
> > > > > > easier to maintain.
> > > > > >
> > > > > > As part of this, we've made some changes to how UFL and FFC handle
> > > > > > the preprocessing of forms. In particular, we've removed the
> > > > > > caching of so called form data in a form. Ideally, this should not
> > > > > > lead to any problems but there may be regressions such as slow JIT
> > > > > > compilation as a result of not caching certain data so keep an eye
> > > > > > out for this.
> > > > >
> > > > > Do you know why Martin did include these in the first place?
> > > >
> > > > Yes, we discussed it quite a bit but I believe he was never happy with
> > > > the solution. We had things like form_data being cached in a form and
> > > > form_data also storing a modified version of the form so there were
> > > > things like
> > > >
> > > >   self.form.form_data().form
> > > >
> > > > being used in the form. I believe the new design is cleaner.
> > >
> > > Ok.
> > >
> > >   v = TestFunction
> > >   u = TrialFunction
> > >
> > >   M0 = assemble(u*v*dx)
> > >
> > >   v = TestFunction
> > >   u = TrialFunction
> > >
> > >   M1 = assemble(u*v*dx)
> > >
> > > I think that he wanted to prevent recompilation of M1, as it is basically
> > > the same code that is generated as for M0. But due to some internal and
> > > necessary they are treated differently. I think that the form_data thing
> > > was a workaround for that. Is this correct?
> >
> > I don't think form_data has anything to do with this.
> >
> > The above code should not lead to any new code generation as both M0
> > and M1 should have the same signatures. If not, there's a bug in
> > jit.py in FFC. The code for M1 should be picked up from disk cache.
>
> Ok, I see that this is not the case for Arguments (BasisFunctions), but it is
> for Coefficients (Functions):
>
>    f = Function(V)
>    u = TestFunction(V)
>
>    m0 = assemble(v*f*dx)
>
>    f = Function(V)
>
>    m1 = assemble(v*f*dx)
>
> will now trigger a recompilation.
>
> Just take a repr on the two 'f' and see.

Should be fixed now. I've added a call to preprocess before computing
the form signature.

Does it work now?

--
Anders

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