Re: [eclipse-users] Finding which constraints failed

From: Vivek Balaraman <vivek.balaraman_at_...6...>
Date: Fri, 31 Aug 2007 08:10:47 +0530
Kish,
Thanks.

I just gave a bared boned version to get comments. I am doing labeling using
locate. I know that a constraint failure does not mean the constraint is
wrong. I however do want to know the circumstances of its failure, i.e. that
constraint x failed given the context of some parameter values. This may
help users to refine values to get solutions. Of course constraint
propagation means that this technique may not be hugely useful since the
constraint failure may be because some other other constraint narrowed
domain values ...

Vivek


On 8/31/07, Kish Shen <kisshen@...5...> wrote:
>
> Vivek Balaraman wrote:
> > I have about 30 constraints in my system and about 40-50 parameters.
> >
> > I'd like to identify which constraint failed for a certain set of
> > parameters both for debugging purposes and to inform the user
> >
> > What are the better ways of doing this?
> >
> > Thanks in advance
> >
> > Vivek
> >
> >
> Since nobody else have replied to you, I will give it a try...
>
> In most applications, posting the constraints will not normally be
> sufficient to cause a failure, or to give you a solution to your
> problem. You need to do some search (i.e. labelling the variables) to
> get a solution (or failure). In this case, it is very hard to tell which
> contraint `failed' if you get a failure, because this will be the result
> of propagation, where generally a lot of propagators are woken and do
> their propagation until eventually the domain of a variable is reduced
> to empty.
>
> If you are trying to catch only the failures while you are posting the
> constraints, then what you do is fine.
> However, the failure here simply means that the constraint posted is
> inconsistent with the constraints you already have, it does not mean it
> is `wrong', even assuming you know that your problem should have a
> solution -- it could be some of your already posted constraints that are
> `wrong'.
>
> Cheers,
>
> Kish
>
>
Received on Fri Aug 31 2007 - 03:40:57 CEST

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