dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Sat, Oct 18, 2008 at 10:16:32PM +0200, Johan Hake wrote:
> On Saturday 18 October 2008 21:24:53 Anders Logg wrote:
> > On Thu, Oct 16, 2008 at 03:38:01PM +0200, Martin Sandve Alnæs wrote:
> > > "in" is a reserved keyword in python. Suggestions: "f.in_space(V)" or
> > > "f.in_function_space(V)" or "f.member(V)"
> >
> > How about keeping u.in(V) in C++ and then map it to something suitable
> > in Python so that one may write
> >
> >   if u in V:
> >       ...
> >
> > in Python. Does anyone know how to do that?
> 
> There is a problem in the logic here. In c++ you ask the function if it is in 
> a certain FunctionSpace, but the python code "u in V" would check if u is in 
> V by calling V.__contains__(u). To make it more consistent we could implement 
> the 'in' function in FunctionSpace, and then just rename 'in' to 
> __contains__. 
> 
> You could also keep it the way it is and then rename Function.in to let say 
> Function._in and then extend FunctionSpace with
> 
>   def __contains__(self,u).
>       assert(u,Function)
>       return u._in(self)
> 
> But then we would have different logics in c++ and python.
> 
> Johan

I think that would be ok, considering it is Python that maps "in" to
"contains". The logic and notation from a user perspective would be
the same in C++ and Python:

  if (u.in(V))
  {
  
  }

  if u in V:

-- 
Anders


> > > As mentioned before, these are not threadsafe:
> > >
> > >     /// Access current cell (available during assembly for
> > > user-defined function)
> > >     const Cell& cell() const;
> > >
> > >     /// Access current facet (available during assembly for
> > > user-defined function)
> > >     uint facet() const;
> > >
> > >     /// Access current facet normal (available during assembly for
> > > user-defined function)
> > >     Point normal() const;
> > >
> > > If we keep these instead of making them arguments to eval,
> > > the user must create one Function for each thread to use
> > > it in a parallell shared memory application.
> >
> > Not necessarily one Function for each thread, but it should be
> > possible to extend Function to keep one cell etc for each thread.
> > The variables are accessed by functions cell(), facet() so it should
> > be possible to hide it.
> 
>

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