dolfin team mailing list archive

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

2008/12/5 Martin Sandve Alnæs <martinal@xxxxxxxxx>:
> 2008/12/5 Johan Hake <hake@xxxxxxxxx>:
>> On Friday 05 December 2008 08:55:44 Martin Sandve Alnæs wrote:
>>> 2008/12/4 Johan Hake <hake@xxxxxxxxx>:
>>> > On Thursday 04 December 2008 20:44:20 Anders Logg wrote:
>>> >> I have moved the jit function and the code from get_dolfin_form to
>>> >> separate modules.
>>> >>
>>> >> The JIT compilation seems to work fine, but the _ufc_form member in
>>> >> the generated dolfin::Form subclass seems to be zero. See comment at
>>> >> the top of the the assemble function.
>>> >>
>>> >> Any ideas what goes wrong? If we get this working, we can remove most
>>> >> of the code from assemble.py and reuse it also in pde.py.
>>> >
>>> > It is fixed now.
>>> >
>>> > This is the same problem we have with the compiled elements and dofmaps
>>> > in FunctionSpace. You need to store a reference to the compiled form,
>>> > otherwise swig will garbage collect the form when it goes out of scope,
>>> > killing also the actuall cpp_ufc_form.
>>>
>>> This is the kind of issue I'm hoping SWIGs shared_ptr bindings can help us
>>> with.
>>
>> True. But I had no luck with it. I do not know where the error resides. I
>> actually made a minimal test .cpp file I wrapped with swig, using both
>> shared_ptr and raw pointers. This behaved as expected. Swig garbage collected
>> the objects stored with raw pointers, but did not do it for the shared_ptr
>> stored one. So it _should_ just work.
>>
>> Johan
>
> Can you share this test code? Details are rather important for this stuff :)
>
> Maybe swig chooses the reference versions of dolfin::foo constructors.
>
> --
> Martin

Since I added the helper function with the nice short name
reference_to_no_delete_pointer, we can add logging in
it to see whenever a reference is put in a shared_ptr.
Might be useful to debug this kind of thing.

--
Martin