ffc team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Apr 26, 2011 at 03:59:52PM +0100, Garth N. Wells wrote:
>
>
> On 26/04/11 15:55, Anders Logg wrote:
> > On Tue, Apr 26, 2011 at 03:45:22PM +0100, Garth N. Wells wrote:
> >>
> >>
> >> On 26/04/11 13:51, Anders Logg wrote:
> >>> On Tue, Apr 26, 2011 at 02:00:50PM +0200, Anders Logg wrote:
> >>>> It feels good that you trust me enough to handle it. ;-)
> >>>>
> >>>> Will add it sometime this afternoon and then we can revisit the JIT
> >>>> compiler caching.
> >>>
> >>> I'm getting confused here... Looking at preprocess.py in UFL, I see this:
> >>>
> >>
> >> It is confusing. Does the function 'preprocess' do anything that the old
> >> FormData class didn't? It would be easier to follow if Form just had a
> >> member function form_data() that computes and stores data (like it used
> >> to), or if Form had a 'preprocess' function. Having the function
> >> preprocess return a new form is really confusing.
> >
> > I don't find that particularly confusing. It's the same as
> >
> >   refined_mesh = refine(mesh)
> >
>
> Which is the whole problem. By creating a new object, FormData is thrown
> away. The preprocessing should just compute some more data, just like we
> *don't* do
>
>   initialised_mesh = mesh.init(0)
>
> What was wrong with Martin's original design that necessitated the change?

As I explained, I thought it was better to have an explicit call to
preprocess since that makes it clear that one makes a call to a
function which may take some time to execute (instead of just calling
a member function which seems to just return some data).

But as I say above: I added the caching back at some point (maybe even
the day after I removed it 2 years ago) so we don't need to discuss
why I removed it (as I realized myself I shouldn't have removed it and
added it back a long time ago).

What has me confused now is that the caching seems to be in place but
we still need the extra caching in FFC/DOLFIN and I don't see why.

--
Anders



> Garth
>
> >> Garth
> >>
> >>>
> >>> def preprocess(form, object_names={}, common_cell=None):
> >>>
> >>>     ...
> >>>
> >>>     # Check that form is not already preprocessed
> >>>     if form.form_data() is not None:
> >>>         debug("Form is already preprocessed. Not updating form data.")
> >>>         return form
> >>>
> >>>     ...
> >>>
> >>>     # Attach form data to form
> >>>     form._form_data = form_data
> >>>
> >>>     # Attach preprocessed form to form data
> >>>     form_data._form = form
> >>>
> >>>
> >>> And when I look at the blamelist (bzr annotate), it looks like I added
> >>> those lines, so I must have come to my senses and added it back at
> >>> some point (way back). So in conclusion, calling preprocess() should
> >>> not taking any time.
> >>>
> >>> What am I missing?
> >>>