dolfin team mailing list archive

[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;
>
> --
> Anders
>
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