[Dune] Returning Geometries As Objects

[Carsten Gräser]

Am 07.02.2012 12:07, schrieb Martin Nolte:
> Hi Oli,
> 
> as far as I understood Christian, he wants the lifetime (I mean the time
> in which the geometry remains valid) to be unlimited before the next
> release. Changing the user code to call geometry only once (which would
> be wise anyway) might take a lot of time and, therefore, I think a
> longer transition period would be good.
> 
> Moreover, I'm still not sure on the correct path. I see at least three
> possibilities:
> 
> A geometry object is valid
> (a) for ever (i.e., as long as it exists)
> (b) as long as the grid, the entity belongs to
Do you mean: 'As long as the grid is not modified.' by this?
Otherwise I suggest this as (b').

Carsten


> (c) as long as the entity exists within the grid
> (d) as long as the corresponding entity pointer is valid (current
> situation)
> 
> I think we should at least prescribe (c), so that, e.g., references to
> the corners are allowed.
> 
> So: What kind of limit on the lifetime of a geometry do you have in mind?
> 
> Best,
> 
> Martin
> 
> 
> 
> On 02/07/2012 11:56 AM, Oliver Sander wrote:
>> This pretty much exactly reflects my view. I don't think I want the
>> reference feature in there either. A variable that looks like an
>> object but is in fact a reference is a big violation of the principle
>> of least surprise. To me, the difficult-to-find bugs that lurk here
>> are far more serious than potential speed loss.
>>
>> Concerning the speed loss: are the measurements of how much loss to
>> expect? And can that not be mitigated in the calling code by making
>> sure to call each geometry-Method only once?
>>
>> best,
>> Oliver
>>
>>>
>>> I'm against a merge, unless we agree to disable the reference feature
>>> before the next release. Yes, this will require updates in all grid
>>> implementations, but I think it is necessary to make this change show
>>> its full potential and to actually value all the work and time you
>>> spent here.
>>>
>>> If we can agree on this, I have no furthe objections regarding a
>>> merge. I think it is well enough tested to actually do a merge. My
>>> main concern is about adding undesired features which we (might) have
>>> to deal with for an unforseable time.
>>>
>>> And "we agree" does not necessarily require a formal vote. I think it
>>> just means that those people involved in (core) grid implementations
>>> have to agree. I, for my part, am willing to do add the necessary
>>> changes. Now we only need an opinion from Robert and Oliver [assuming
>>> that you actually want to use you new feature ;-)].
>>>
>>> Cheers
>>> Christian