Martin Sandve Alnæs wrote:
> 2007/7/25, Anders Logg <[EMAIL PROTECTED]>:
>> 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.
I also thought of naming it copy(), but this is not alwats appropriate.
In DiscreteFunction, one needs to create a new vector which is not a
copy (but which is a copy of a slice of the vector). Having a copy()
function might be useful, but one can create a new object and then copy
the values by get/set.
> 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
Why not place it as a member function in GenericFoo? Then we avoid
having a number of additional classes (PETScVectorFactor,
PETScMatrixFactory, uBlasVectorFactory, ...).
/Anders
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