VecGhost and state

[Matthew Knepley]

On Thu, Apr 30, 2009 at 9:08 AM, Jed Brown <jed at 59a2.org> wrote:

> Matthew Knepley wrote:
>
> > I am opposed to this, because I really do not like the state mechanism
> > in the first place. It is dangerous (as your debugging shows), and
> > relying on it makes it very easy for people to introduce errors, as we
> > see.
>
> It is dangerous, but it's nice to just call VecNorm wherever you need it
> without worrying about it being wasteful.
>
> In any case, using the maximum scheme and syncronization, the state will
> change any time you change either vector, as long as that vector's state
> is increased when you change it (which is already required for any
> vector).
>

But any time someone creates a new mechanism, they have to respect this.
This is why when the local vector mechanism was introduced, it broke this
immediately.

Programming should not be about what will do the job, but also what
is transparent and robust. This is neither.


> > However, if you really want to synchronize the state of local and
> > global vectors, I will not stop it this time. If there is another
> > error, I am wiping this out altogether.
>
> Wiping what out?  VecGhost?  State?


I mean if this breaks something else, we will go to a conservative scheme.
I still prefer that.

  Matt


>
> Jed
>

-- 
What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
lead.
-- Norbert Wiener
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