dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Sat, Nov 28, 2009 at 12:50:49AM -0800, Johan Hake wrote:
> On Saturday 28 November 2009 00:45:39 Garth N. Wells wrote:
> > Johan Hake wrote:
> > > On Friday 27 November 2009 14:44:12 Garth N. Wells wrote:
> > >> Johan Hake wrote:
> > >>> On Friday 27 November 2009 11:53:00 Garth N. Wells wrote:
> > >>>> Johan Hake wrote:
> > >>>>> On Friday 27 November 2009 03:02:08 Anders Logg wrote:
> > >>>>>> On Fri, Nov 27, 2009 at 09:41:03AM +0000, Garth N. Wells wrote:
> > >>>>>>> Anders Logg wrote:
> > >>>>>>>> On Fri, Nov 27, 2009 at 08:37:08AM +0000, Garth N. Wells wrote:
> > >>>>>>>>> Is it still possible with the new Expression syntax to do
> > >>>>>>>>> something like:
> > >>>>>>>>>
> > >>>>>>>>>  f2, f3 =
> > >>>>>>>>> Expressions("sin(3.0*x[0])*sin(3.0*x[1])*sin(3.0*x[2])", "1.0 +
> > >>>>>>>>> 3.0*x[0] + 4.0*x[1] + 0.5*x[2]", V=V)
> > >>>>>>>>>
> > >>>>>>>>> The above is used in the unit tests. Or to keep things simple
> > >>>>>>>>> should we remove this kind of fancy feature?
> > >>>>>>>>
> > >>>>>>>> I guess it's a nice feature to have but it's nothing I care that
> > >>>>>>>> much for.
> > >>>>>>>
> > >>>>>>> All tests except the unit test for function are working. Expression
> > >>>>>>> needs to be updated for some of the fancier syntax.
> > >>>>>>>
> > >>>>>>> Garth
> > >>>>>>
> > >>>>>> I made a very simple fix in expression.py to get Expressions()
> > >>>>>> working.
> > >>>>>>
> > >>>>>> It currently createas a separate Expression class for each argument
> > >>>>>> so it will call compile_expressions() for each one, which is less
> > >>>>>> efficient than compiling a bunch of expressions at once.
> > >>>>
> > >>>> Doesn't seem to work when I tried.
> > >>>>
> > >>>>> The whole point of using Expressions, is to avoid double compilations
> > >>>>>
> > >>>>> :)
> > >>>>>>
> > >>>>>> Johan, could you have a look at this function?
> > >>>>>>
> > >>>>>> I also commented out the unit test testSameBases since I couldn't
> > >>>>>> figure out what it's supposed to do or if it is still valid after
> > >>>>>> the interface changes.
> > >>>>>>
> > >>>>>> Please have a look.
> > >>>>>
> > >>>>> Will do!
> > >>>>
> > >>>> I had a look, but haven't committed anything yet.
> > >>>
> > >>> Commit anything if you like. I have time to look at it this evening
> > >>> (night for you ;))
> > >>
> > >> I'll leave it to you because expression.py is leaving me confused,
> > >> namely why does Expression involve the metaclass ExpressionMetaClass,
> > >> but Expressions doesn't? As a result why do we want the __init__
> > >> function defined inside create_expression_class to be called for an
> > >> Expression but not the expressions in an Expressions?
> > >
> > > Ok, I'll look at it.
> > >
> > > create_expression_class is called in Expressions. It is used to create
> > > the full fledged Expression class that inherits, dolfin.Expression,
> > > ufl.Function and the newly compiled class that inherits cpp.Expression.
> >
> > It would help me if someone could tell when when the __init__ function
> > defined inside function 'create_expression_class' is called. When I do
> >
> >   f1 = Expression("2", degree=2)
> >
> > the __init__ function is called, but when I do
> >
> >   f2,f3 = Expressions("2", "1", degree=2)
> >
> > the __init__ function is not called.
>
> My expression.py is in a mess, so I wont be able to debug it right now. And
> it's getting late here ;)
>
> How do we want to handle Expressions together with degree, and element. Should
> they all be initialized using the same elements and/or degree? That's the most
> obvious choice.

I think that would be enough yes. It would simplify the interface:

  f, g, h = Expressions("...", "...", "...", kwargs)

--
Anders




> Johan
>
> > Garth
> >
> > > Whenever a class is created that either is or inherits dolfin.Expression,
> > > the ExpressionMetaClass.__new__ is employed. However we do not want to
> > > make any costumizations in classes returned by create_expression_class,
> > > which means we just want to return the class as it is passed to the
> > > ExpressionMetaClass.__new__ method. Therefore I have the lines 213-217,
> > > which just do that.
> > >
> > > Put
> > >
> > >   print name, bases
> > >
> > > first in the ExpressionMetaClass.__new__ method and try to create some
> > > user defined Expressions, and you might get a clue of what is happening.
> > >
> > > Johan
> > >
> > >> There is a lot of magic going on which makes it hard to follow.
> > >>
> > >> Garth
> > >>
> > >>> Johan
> > >>>
> > >>>> Garth
> > >>>>
> > >>>>> Johan
> > >>>>>
> > >>
> > >> _______________________________________________
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> >
>
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