[Dune] Default constructor in MultiLinearGeometry

[Martin Nolte]

Hi Oli,

as far as I can see, this would in priciple possible if the corner storage has a 
default constructor (like std::vector) and _no_ methods are called on this geometry.

Personally, I feel like the wrong instance to decide upon this question.

Not knowing much about the UGGrid code, I don't see why you ever want an 
uninitialized geometry. From my point of view, you either construct the geometry 
directly before returning it (not holding a copy on the entity), or you do it 
like GeometryGrid and hold a reference counting pointer on the entity. As this 
might be a nullptr, you don't need a default constructor, here.

Apart from this, my feeling is that uninitialized objects are a very bad thing. 
Especially unexperienced programmers will have a hard time finding bugs caused 
by this. A default constructor would, of course, create an "uninitialized" 
geometry (in the sense that you may not use it at all).

Should this question be discussed on the FlySpray?

Best,

Martin

PS: Thanks for all the positive feedback. I was not sure whether this change is 
the right path or not.

On 10/14/2012 09:03 AM, Oliver Sander wrote:
> Hi Martin,
> last night I tried to switch from BasicGeometry to MultiLinearGeometry
> for various parts of UGGrid. Unfortunately, that didn't work as easily
> as I hoped, because UGGrid expects a default constructor, which
> BasicGeometry has, and MultiLinearGeometry hasn't. Is there any chance
> to get a default constructor in MLG, or should a adjust the UGGrid code?
> best,
> Oliver
>
> _______________________________________________
> Dune mailing list
> Dune at dune-project.org
> http://lists.dune-project.org/mailman/listinfo/dune

-- 
Dr. Martin Nolte <nolte at mathematik.uni-freiburg.de>

Universität Freiburg                                   phone: +49-761-203-5630
Abteilung für angewandte Mathematik                    fax:   +49-761-203-5632
Hermann-Herder-Straße 10
79104 Freiburg, Germany