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[Anders Logg <logg@xxxxxxxxx>]

On Tue, Feb 17, 2009 at 04:37:20PM +0000, A Navaei wrote:
> 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.

Can you extend the sandbox code to [2] (in the simplest possible way)
and I can take a look.

-- 
Anders


> -Ali
> 
> > Also, the above answered question (2).
> >
> >
> > -Ali
> >
> >>>
> >>>
> >>> -----BEGIN PGP SIGNATURE-----
> >>> Version: GnuPG v1.4.9 (GNU/Linux)
> >>>
> >>> iEYEARECAAYFAkma5H0ACgkQTuwUCDsYZdFvpwCdFb7i80BdC7XDqxwbtlr28FV0
> >>> g30AnjcDnux+6kRuTBSKdnhtKAnV7zuz
> >>> =ri5f
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> >>>
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