dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

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?

--
Anders

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