ffc team mailing list archive

[Marie Rognes <meg@xxxxxxxxx>]

On 18. juni 2010 16:23, Kristian Oelgaard wrote:
> On 18 June 2010 15:25, Mehdi <m.nikbakht@xxxxxxxxxx> wrote:
>   
>>
>> If we want to address this issue, the same concept should be also
>> considered for ElementRestriction. What would we expect if we enrich a
>> vector element with a restricted vector element?
>>
>>  V = VectorElement("CG", "triangle", 1)
>>  B = ElementRestriction(V, dc)
>>
>>  W = V + B
>>
>> Since this restricted element is not vector element anymore.
>>     
> Can't we just check, inside the '+' operator, if an element is an
> ElementRestriction and then if the restricted element is a
> VectorElement
> BTW, shouldn't it be RestrictedElement (like EnrichedElement) rather
> than ElementRestriction?
>
>   

Yes, that would be more consistent.


> Another possibility is to propagate the restriction to the subelements
> when creating the restricted element and then return a VectorElement
> with restricted sub elements. Did we try that and fail at some point?
> I forgot.
>
>   


FFC does do this for its internal representation of restricted elements...

--
Marie



> Kristian
>
>   
>> Yours,
>> Mehdi
>>
>>
>>     
>>> Kristian
>>>
>>>       
>>>> Another advantages of using this approach is we don't need to define
>>>> unnecessary scaler elements to just get mixed enriched element. The
>>>> approach of defining scaler elements can be annoying, if we want to use
>>>> both enriched and non-enriched vector elements(which is the case often
>>>> for me).
>>>>
>>>> If we overload +, it is just enough to have:
>>>>
>>>> V = VectorElement("CG", "triangle", 1)
>>>> B = VectorElement("B", "triangle", 3)
>>>> M = V + B
>>>>
>>>> We can use M and V both to define our functions.
>>>>
>>>>
>>>> This is definitely and advantage.
>>>>
>>>>
>>>>
>>>> If we want to extend VectorElement, this would be,
>>>>
>>>> V1 = FiniteElement("CG", "triangle", 1)
>>>> B1 = FiniteElement("B", "triangle", 3)
>>>> M = VectorElemnet(V1 + B1)
>>>>
>>>>
>>>> But we can still extend the vector element to enable this it you think
>>>> it will be useful, that was the essence of my earlier and confusing
>>>> remark which should have been:
>>>>
>>>> 'We CAN of course still do this even if we decide on option 1)'
>>>>
>>>>
>>>> Ok, sentence makes sense now!
>>>>
>>>> --
>>>> Marie
>>>>
>>>>         
>>
>>