ffc team mailing list archive

[Martin Sandve Alnæs <martinal@xxxxxxxxx>]

Look at the latest commit.

Martin



On Fri, Apr 17, 2009 at 2:29 PM, Garth N. Wells <gnw20@xxxxxxxxx> wrote:
>
>
> Anders Logg wrote:
>> On Fri, Apr 17, 2009 at 03:57:09PM +0800, Garth N. Wells wrote:
>>>
>>> Anders Logg wrote:
>>>> On Fri, Apr 17, 2009 at 03:07:17PM +0800, Garth N. Wells wrote:
>>>>> Anders Logg wrote:
>>>>>> On Fri, Apr 17, 2009 at 08:59:43AM +0200, Johan Hake wrote:
>>>>>>> On Friday 17 April 2009 03:32:26 Garth N. Wells wrote:
>>>>>>>> Should we start moving to UFL-based forms for the DOLFIN demos? Is the
>>>>>>>> only serious outstanding issue on the FFC side the correct determination
>>>>>>>> of the quadrature order?
>>>>>>> Not sure how this could be best done in PyDOLFIN.
>>>>>>>
>>>>>>> We could add
>>>>>>>
>>>>>>>   from dolfin.ufl import *
>>>>>>>
>>>>>>> after each
>>>>>>>
>>>>>>>   from dolfin import *
>>>>>>>
>>>>>>> in the demos. When this is done and it all just works(TM) we can move the
>>>>>>> files in the site-packages/dolfin/ufl directory down to site-packages/dolfin,
>>>>>>> and remove
>>>>>>>
>>>>>>>   from dolfin.ufl import *
>>>>>>>
>>>>>>> from the demos?
>>>>>>>
>>>>>>> Johan
>>>>>> I suggest we just move everything to UFL at once and then solve any
>>>>>> problems that we encounter.
>>>>>>
>>>>>> I'm intending to remove the .form support from FFC quite soon (maybe
>>>>>> today).
>>>>>>
>>>>>> It's easier to fix things so that they work with UFL than to have two
>>>>>> conflicting form languages work at the same time.
>>>>>>
>>>>> The quadrature issue is serious, so I think that it should be tackled
>>>>> before the transition, or at least a short-term plan for how to solve it
>>>>> should be in place.
>>>>>
>>>>> Garth
>>>> Is it so serious? It's a small thing compared to what will happen when
>>>> the .form support is removed from FFC (as in everything will be broken
>>>> until fixed).
>>>>
>>> Results computed with the new and old formats will not, in general, be
>>> the same, so I considered it to be serious.
>>
>> Yes, they won't be the same but I thought they would still be correct
>> (as in possibly using a better quadrature rule than needed).
>>
>
> No, it uses a lower degree of quadrature. For example, for the Poisson
> demo using the new UFL format only one quadrature point is used for the
> source term, whereas enough points for a quadratic polynomial are required.
>
> Not quite sure what 'not the same but still correct' means ;).
>
> Garth
>
>
>> Kristian?
>>
>
>
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