dolfin team mailing list archive

[Johan Hake <johan.hake@xxxxxxxxx>]

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.

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
> >>>>>
> >>>>>> --
> >>>>>> Anders
> >>
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