ffc team mailing list archive

[Martin Sandve Alnæs <martinal@xxxxxxxxx>]

SFC doesn't use the same quadrature rules as
FFC, so that makes no sense in my head.
Either install SyFi properly with dependencies,
or keep using FFC and ignore my suggestion.

(If you still want them, the rules SFC use are in
site-packages/sfc/quadrature/quad_tables.py)

Martin



On Mon, Jun 22, 2009 at 11:09 PM, Shawn Walker<walker@xxxxxxxxxxxxxxx> wrote:
> Actually, would it be possible for you to just give me the 4-pt quad rule on
> a triangle.  The problem is, I don't have GiNAC setup, which is needed to
> run SyFi, right?
>
> - Shawn
>
> On Mon, 22 Jun 2009, Martin Sandve Alnæs wrote:
>
>> Ok. Temporarily, maybe you'll be happy with the code
>> generated by SFC (see the demo/*/cpp/ directories in SyFi).
>> There both weights and points are embedded directly in the code.
>>
>> Martin
>>
>>
>>
>> On Mon, Jun 22, 2009 at 10:50 PM, Shawn Walker<walker@xxxxxxxxxxxxxxx>
>> wrote:
>>>
>>>
>>> On Mon, 22 Jun 2009, Anders Logg wrote:
>>>
>>>> I think Shawn just wants to get the quadrature points so he can
>>>> hand-modify the code for tabulate_tensor to handle higher-order mapped
>>>> elements (to make a prototype for higher-order elements).
>>>>
>>>> Correct me if I'm wrong.
>>>
>>> Yes!
>>>
>>>> In that case, we won't need to make them available since they are
>>>> available to the form compiler when the code is being generated, but
>>>> it would help if they were available in a comment in the generated code.
>>>
>>> I agree that having them in a comment would be good.
>>>
>>> - Shawn
>>>
>>>>
>>>> On Mon, Jun 22, 2009 at 10:28:29PM +0200, Martin Sandve Alnæs wrote:
>>>>>
>>>>> On Mon, Jun 22, 2009 at 9:10 PM, Kristian
>>>>> Oelgaard<k.b.oelgaard@xxxxxxxxxx> wrote:
>>>>>>
>>>>>> Quoting Shawn Walker <walker@xxxxxxxxxxxxxxx>:
>>>>>>
>>>>>>> Actually, I am still a little confused.  Whenever you compute an
>>>>>>> integral
>>>>>>> by quadrature, you need to evaluate the integrand at the quadrature
>>>>>>> points.  Those are the points I need.
>>>>>>
>>>>>> If you have a quadrature element in your form
>>>>>>
>>>>>> element = FiniteElement("Quadrature", triangle, 2)
>>>>>>
>>>>>> you can call the
>>>>>> tabulate_coordinates() function of the dof_map associated with the
>>>>>> quadrature
>>>>>> element. If you don't have a quadrature element there is no direct way
>>>>>> of
>>>>>> getting the quadrature points.
>>>>>>
>>>>>>> I just need the quad rule that is used in a particular case.  I see
>>>>>>> the
>>>>>>> weights are defined in the tabulate_tensor routine.  Are the points
>>>>>>> listed
>>>>>>> in a comment somewhere?
>>>>>>
>>>>>> No, currently not. But it might be a natural thing to have. I'll look
>>>>>> into it.
>>>>>
>>>>> It could be an idea to make it available through UFC,
>>>>> but then again each ufc::*_integral may use different
>>>>> quadrature rules for different terms...
>>>>> However, an exception can be thrown if there is no unique rule in use.
>>>>>
>>>>> Martin
>>>>> _______________________________________________
>>>>> FFC-dev mailing list
>>>>> FFC-dev@xxxxxxxxxx
>>>>> http://www.fenics.org/mailman/listinfo/ffc-dev
>>>
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>>>
>>
>