On Thu, Feb 10, 2011 at 08:44:21AM +0000, Garth N. Wells wrote: > > > On 10/02/11 07:19, Anders Logg wrote: > > B1;2600;0cOn Wed, Feb 09, 2011 at 11:03:28PM +0000, Garth N. Wells wrote: > >> > >> > >> On 09/02/11 22:43, Anders Logg wrote: > >>> On Wed, Feb 09, 2011 at 10:11:40AM -0800, Johan Hake wrote: > >>>> Hello! > >>>> > >>>> I am pretty sure the reason the Macbot still complains (mesh unit test) > >>>> is > >>>> that refine is broken for SWIG 2.0. > >>>> > >>>> I think it is some premature destruction of a refined mesh. I would > >>>> suggest we > >>>> implement a full shared_ptr version of the interface to get around this > >>>> problem. I have no clue of why it works for SWIG 1.3.40. Probably > >>>> because a > >>>> faulty implementation. > >>>> > >>>> I also suggest more developers upgrade to SWIG 2.0.1 and maybe one of the > >>>> linux build bots two? If it is only the Macbot that uses SWIG 2.0 it is > >>>> easily > >>>> to think it is some Mac specific error. > >>>> > >>>> Johan > >>> > >>> I plan to merge with main tomorrow if my buildbot is green. Then Marie > >>> also needs to merge (we have both touched refine.h/cpp). Then we can > >>> sort out the shared_ptrs. > >>> > >> > >> I really don't get the approach to hierarchies. Mesh refinement was > >> simple, and now something simple has become complex (with bugs that are > >> hard to track down because of the introduced complexity). > > > > I really don't understand what the problem is. Mesh refinement is just > > as simple as it used to be, the Mesh class itself is (almost) as > > simple as it used to be (one added inheritance), and the Hierarchical > > base class is also a very simple class (just stores two pointers for > > child and parent). All the complexity is in refine.cpp, which only > > kicks in if you do something like refine(variational_problem) or > > refine(function_space). > > > >> This hierarchy business looks viral - now I get Swig warnings for > >> DirichleBC. > >> > >> I would much rather keep basic classes simple, and have hierarchical > >> containers that can keep track of parent/child relationships. The > >> present approach seems to take a narrow/immediate view on the issue. > > > > I think that would lead to more complex code. We would need to store > > quite a few different relationship trees separately from the objects. > > > > The problems we see now are related to SWIG and correct use of > > shared_ptrs. We've had quite a few SWIG/shared_ptr problems in the > > past and figured out how to fix them. I'm sure we will handle this > > too. > > > > I would like to remove the mesh refine functions, or re-write them. My > objections to the current implementation are: > > - It forces a mesh hierarchy on users, even if this is not desired
It doesn't. Normal users will do mesh = refine(mesh); and then no hierarchy is stored (in C++). It would be very easy to add a parameter "store_hierarchy" which defaults to false if that is desired. > - It is not const-correct. I believe it is const-correct in Marie's branch. > - The 'parent' can go out of scope, leaving the 'child' with a dangling > pointer. It shouldn't go out of scope since we use shared ptrs. It's the same issue as everywhere else where we pass by reference and use reference_to_no_delete_pointer. It's not special for the refinement functions. -- Anders > We should be very particular about const-correctness throughout (i.e. > not use const_cast unless absolutely necessary) because it makes > multi-threading *much* easier to develop. > > Garth > _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
