ffc team mailing list archive

["Martin Sandve Alnæs" <martinal@xxxxxxxxx>]

2008/12/6 Garth N. Wells <gnw20@xxxxxxxxx>:
>
>
> Martin Sandve Alnæs wrote:
>>
>> 2008/12/6 Garth N. Wells <gnw20@xxxxxxxxx>:
>>>
>>> It would be useful if we could somehow associate names with mixed
>>> functions, e.g.
>>>
>>>  P2 = VectorElement("Lagrange", "triangle", 2)
>>>  P1 = FiniteElement("Lagrange", "triangle", 1)
>>>  TH = P2 + P1
>>>  (u, p, "U") = Functions(TH)
>>>
>>> so that in the DOLFIN-specific C++ wrapper code we can use
>>>
>>>  a.U = u;
>>>
>>> to attach mixed functions rather than
>>>
>>>  a.w0 = u;
>>>  a.w1 = v;
>>>  etc.
>>>
>>> which is error prone. Andy suggestions on a nice way to do this in the
>>> FFC input? Will this be part of UFL?
>>>
>>> Garth
>>
>> I get the problem and idea, but I don't get this code example. You
>> can't assign to "U".
>>
>
> The example isn't a suggestion, just an illustration that I would somehow
> like to associate the name "U" with the mixed function.
>
>> Also, I think we should remove "Functions" from UFL, using "split"
>> explicitly instead:
>>
>> U = Function(TH)
>> u, p = split(u)
>>
>> then we will have:
>>
>> a.U = u; // mixed function
>>
>> in the dolfin code.
>>
>
> That would be nice.
>
>> We can add a name attribute to Function in UFL, but I
>> removed this a short while ago to keep things simple...
>> Then this would do the same:
>>
>> u, p = split(Function(TH, name="U"))
>>
>
> The first of your examples look simpler to me.
>
> Garth

Good! I'll make it happen (for UFL).

(I'm hoping to get a basic UFL-based form compiler up and
running before christmas, with most features in place).

--
Martin