dolfin team mailing list archive

[Johan Hake <hake@xxxxxxxxx>]

On Monday 21 September 2009 08:42:21 Anders Logg wrote:
> On Mon, Sep 21, 2009 at 07:58:52AM +0200, Johan Hake wrote:
> > On Sunday 20 September 2009 23:02:31 Anders Logg wrote:
> > > Is it possible to add member functions to JIT-compiled C++ functions
> > > that will be accessible in Python?
> > >
> > > I want to do something like
> > >
> > > code = """
> > > class MyFunction : public Function
> > > {
> > > public:
> > >
> > >   std::vector<double> _values;
> > >
> > >   MyFunction(FunctionSpace& V) : Function(V) {}
> > >
> > >   void eval(double* values, const Data& data) const
> > >   {
> > >     values[0] = _values[data.cell().index()];
> > >   }
> > >
> > >   void update(stuff)
> > >   {
> > >     // Recompute _values here
> > >   }
> > >
> > > };"""
> > >
> > > When I try this, the update() function is not accessible from Python.
> >
> > This works like a charm!
> >
> > from dolfin import *
> >
> > code = """
> > class MyFunction : public Function
> > {
> > public:
> >
> >   std::vector<double> _values;
> >
> >   MyFunction(boost::shared_ptr<FunctionSpace> V) : Function(V) {}
> >
> >   void eval(double* values, const Data& data) const
> >   {
> >     values[0] = _values[data.cell().index()];
> >   }
> >
> >   void update()
> >   {
> >       std::cout << "done" << std::endl;
> >     // Recompute _values here
> >   }
> >
> > };
> > """
> >
> > mesh = UnitSquare(2,2)
> > V = FunctionSpace(mesh,'CG',1)
> > f = Function(V,code)
> > f.update()
> 
> Thanks!
> 
> The problem was I couldn't get it to compile (missing the shared_ptr
> stuff) so I tried doing
> 
>   f = Function(V, code=code)
> 
> which seemed to work. Only it didn't... The code=code keyword argument
> was just ignored (or perhaps used to set an attribute?). And then my
> update() function was missing.
> 
> Should there be some check for keyword arguments like the one above?

Ahh!

I think the **kwargs is an artifact from some deprecated functionality.

It is removed now.

Johan