On Tuesday April 26 2011 09:18:15 Garth N. Wells wrote: > On 26/04/11 17:16, Anders Logg wrote: > > On Tue, Apr 26, 2011 at 06:12:26PM +0200, Martin Sandve Alnæs wrote: > >> On 26 April 2011 18:10, Johan Hake <johan.h...@gmail.com> wrote: > >> On Tuesday April 26 2011 09:01:35 Anders Logg wrote: > >> > On Tue, Apr 26, 2011 at 08:44:24AM -0700, Johan Hake wrote: > >> > > On Tuesday April 26 2011 08:42:32 Anders Logg wrote: > >> > > > On Tue, Apr 26, 2011 at 08:39:30AM -0700, Johan Hake wrote: > >> > > > > On Tuesday April 26 2011 08:33:11 Garth N. Wells wrote: > >> > > > > > On 26/04/11 16:31, Johan Hake wrote: > >> > > > > > > On Tuesday April 26 2011 08:16:29 Garth N. Wells wrote: > >> > > > > > >> On 26/04/11 16:07, Anders Logg wrote: > >> > > > > > >>> 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. > >> > > > > > >> > >> > > > > > >> Because preprocess returns a new form, e.g. define a > >> > > > > > >> form > >> > > > > > >> > >> > > > > > >> a = u*v*dx > >> > > > > > >> jit(a) > >> > > > > > >> > >> > > > > > >> Inside jit, > >> > > > > > >> > >> > > > > > >> a.form_data() is None: > >> > > > > > >> b = preprocess(a) # b now has data attached, but > >> > > > > > >> a doesn't > >> > > > > > >> > >> > > > > > >> else: > >> > > > > > >> b = a > >> > > > > > >> > >> > > > > > >> Now 'b' has been preprocessed, and has form data > >> > > > > > >> attached, but 'a' doesn't. Calling 'jit(a)' again, the > >> > > > > > >> code will never enter the 'else' part of the clause > >> > > > > > >> because 'a' never gets any form data. Johan has added > >> > > > > > >> some code FFC that attaches the form > >> > >> data > >> > >> > > > > > >> of 'b' to 'a', but it is a bit clumsy. > >> > > > > > > > >> > > > > > > No, it was already attached. I just made ffc use it. > >> > > > > > > >> > > > > > Didn't you add the line > >> > > > > > > >> > > > > > form._form_data = preprocessed_form.form_data() > >> > > > > > >> > > > > No, I added: > >> > > > > preprocessed_form = form.form_data()._form > >> > > > > > >> > > > > I think the thing here is that form_data has always had a > >> > > > > preprocessed form. Someone (lets not point fingers!) thought > >> > > > > that was too much magic and added an > >> > > > > > >> > > > > explicit need to call: > >> > > > > form = preprocess(form) > >> > > > > > >> > > > > in jit_compiler(). This made the design more complicated and > >> > > > > also introduced a cirucular dependency, as the return > >> > > > > preprocessed form need to know of its form_data, but the > >> > > > > form_data already had a reference to the preprocessed form. > >> > > > > The latter is what I used in > >> > >> the > >> > >> > > > > one line I altered. > >> > > > > >> > > > No, it made the design cleaner since it makes clear something > >> > > > needs > >> > >> to > >> > >> > > > happen to get the metadata: a call to preprocess. > >> > > > > >> > > > Where did you add this line? > >> > > > >> > > I change > >> > > > >> > > preprocessed_form = form > >> > > > >> > > to: > >> > > preprocessed_form = form.form_data()._form > >> > > >> > Yes, but where? > >> > > >> > I've fixed the bug now in preprocess.py (attaching to both forms). > >> > Does that help? > >> > >> In ffc.jit_form. > >> > >> Your fix wont fix the circular dependency. > >> > >> We also need to remove form_data from the preprocessed form. > >> > >> Or just use a weakref. > >> > >> This means that > >> we need to return form_data from preprocess and maybe change its > >> name to compute_form_data. > >> > >> Johan > > > > Why is the circular dependency a problem? Anyway, I'm thinking now the > > cleanest design would be > > > > form.compute_form_data() > > form_data = form.form_data() > > preprocessed_form = form_data.preprocessed_form > > > > Here, the preprocessed_form would not store form_data. > > Agree.
Go for it! We would then also avoid problems with ciruclar dep. Still think form.compute_form_data() line is superflous ;) Johan > Garth > > > -- > > Anders _______________________________________________ Mailing list: https://launchpad.net/~ffc Post to : ffc@lists.launchpad.net Unsubscribe : https://launchpad.net/~ffc More help : https://help.launchpad.net/ListHelp
