dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

On 22 February 2013 13:13, Johan Hake <hake.dev@xxxxxxxxx> wrote:
> Any comment on this?
>
> Basically we need another constructor which generates a shallow copy of
> a Function, which also has access to the original Function.
>

Would this be a non-issue if using a shared_ptr? What's the difference
between a shallow copy of a Function and a pointer to a Function?

Garth

> Johan
>
> On 02/21/2013 07:08 PM, Johan Hake wrote:
>> Hello!
>>
>> To fix:
>>
>> [child().child() fails for Function and FunctionSpaces in Python]
>> https://bugs.launchpad.net/bugs/1130354
>>
>> we need to add a way of shallow copy a Function. For now we have used:
>>
>> Function(boost::shared_ptr<const FunctionSpace> V,
>>          boost::shared_ptr<GenericVector> x);
>>
>> Which create a new Function with a shared FunctionSpace and
>> GenericVector. The problem is that there is no way of bringing
>> Hierarchical data to the new Function as it is not passed through the
>> constructor.
>>
>> We would need something like:
>>
>> Function(boost::shared_ptr<const Function> u);
>>
>> which is interpreted as a shallow copy.
>>
>> We could then map this to:
>>
>>   Function._shallow_copy()
>>
>> and
>>
>>   Function(const Function& u);
>>
>> to
>>
>>   Function._deep_copy()
>>
>> in the Python interface. Then we add:
>>
>>   Function.
>>
>>   def copy(self, deepcopy=True):
>>      if deepcopy:
>>         return self._deep_copy()
>>      else:
>>         return self._shallow_copy()
>>
>> Any objections to adding:
>>
>>   Function(boost::shared_ptr<const Function> u);
>>
>> as a shallow copy constructor?
>>
>> If so we could maybe remove:
>>
>>    Function(boost::shared_ptr<const FunctionSpace> V,
>>             boost::shared_ptr<GenericVector> x);
>>
>> as I think we added it so we could create a shallow copy in the Python
>> interface.
>>
>> Johan
>>
>
>
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