dolfin team mailing list archive

[A Navaei <axnavaei@xxxxxxxxxxxxxx>]

2009/2/17 A Navaei <axnavaei@xxxxxxxxxxxxxx>:
> 2009/2/17 A Navaei <axnavaei@xxxxxxxxxxxxxx>:
>> 2009/2/17 Anders Logg <logg@xxxxxxxxx>:
>>> On Tue, Feb 17, 2009 at 04:06:50PM +0000, A Navaei wrote:
>>>> 2009/2/17 Anders Logg <logg@xxxxxxxxx>:
>>>> > On Tue, Feb 17, 2009 at 03:59:51PM +0000, A Navaei wrote:
>>>> >> 2009/2/17 A Navaei <axnavaei@xxxxxxxxxxxxxx>:
>>>> >> > The following minimal test for Function in c++ reveals some bugs. I
>>>> >> > guess this example can help me with dealing with the current issues of
>>>> >> > ImageFunction.
>>>> >> >
>>>> >> > (1) interpolate.py does not work when a Function is created in c++ and
>>>> >> > wrapped (see comment [2]). It seems that the bug is originated from
>>>> >> > the copy constructor (see comment [3])
>>>> >> >
>>>> >> > (2) In order to perform the interpolation, why is it necessary to
>>>> >> > create another Function and then copy it?
>>>> >> >
>>>> >> > (3) Signature checkes seem not working properly (see comment [1]). The
>>>> >> > signature-based assignments are error-prone anyway, why the
>>>> >> > object-oriented approach is not used?
>>>> >> >
>>>> >> >
>>>> >> I'm adding another issue:
>>>> >>
>>>> >> (4) Sub-classing Function and calling the sub-class interpolate()
>>>> >> function does not call eval().
>>>> >
>>>> > Which interpolate() function? There are 4 different.
>>>>
>>>> The one used in comment [4].
>>>
>>> Yes, I see that now. This is expected behavior. The reason is that the
>>> call to vector() will create a zero vector if there is no vector. Once
>>> the vector has been created, the Function will change from being a
>>> user-defined function to a discrete function which means that eval()
>>> will not be called.
>>>
>>> I don't know what the best solution is. We could either add a new
>>> function just called interpolate() without arguments that interpolates
>>> the function to its function space.
>>
>> I think this is a good idea, as calling
>>
>> v.interpolate(v.vector(), v.function_space());
>>
>> is somehow pointless.
>>
>>
>> -Ali
>>
>>> Or one can work around it by
>>>
>>>  Vector x;
>>>  v.interpolate(x, v.function_space());
>>>  v.vector() = x;
>
> This is what interpolate.py does. Like I explained in (1), this is
> buggy when Function is created in c++ and then wrapped in python.

Also it doesn't work in pure c++ (the work around is already given in
the test code). Please try comment [2] in sandbox.


-Ali

> Also, the above answered question (2).
>
>
> -Ali
>
>>>
>>> --
>>> Anders
>>>
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>>
>