dolfin team mailing list archive

["Martin Sandve Alnæs" <martinal@xxxxxxxxx>]

2007/7/25, Anders Logg <logg@xxxxxxxxx>:
> Garth N. Wells wrote:
> > Anders Logg wrote:
> >> I think there is a very simple solution. We just change the
> >> constructor of Function to
> >>
> >>     Function(Mesh& mesh, GenericVector& x, const Form& form, uint i = 1)
> >>
> >> and the vector member of DiscreteFunction to
> >>
> >>     GenericVector* x;
> >>
> >> Then if one needs a Function that uses a particular linear algebra
> >> backend, then just create the Function from a PETScVector, uBlasVector
> >> or EpetraVector. Otherwise, create it from a Vector (tied to the
> >> default backend) or let the Function itself decide (in which case it
> >> will be a Vector).
> >>
> >
> > I thought that this would be a simple solution, but there a "new Vector"
> > in DiscreteFunction which requires that the vector type be known. If
> > this is somehow re-written, the above approach could be used.
> >
> > Garth
>
> This is used to create copies of the vector (when creating a sub
> function or in the copy constructor). How about adding a factory
> function to GenericVector? (And also to GenericFoo in general.)
>
>      virtual GenericVector* create() = 0;
>
> Then we can call this instead of new Vector() in DiscreteFunction.cpp.
>
> /Anders

I already have this in pycc::GenericVector/Foo, but I call it "copy",
which I think is a better name.

For eventual other situations which require type-independent
construction of GenericFoo without an object to copy, we can have a
factory design:

class GenericFooFactory
{
public:
 GenericFoo * create_foo(...) const = 0;
 ...
};

This is implemented for each backend, and create_foo can be defined
with several different argument lists.

Martin