Re: [eclipse-users] 'forall' predicate

From: Ulrich Scholz <ulrich.scholz_at_...10...>
Date: Thu, 29 Mar 2007 10:54:51 +0200
On Thu, Mar 29, 2007 at 01:02:10PM +1000, Malcolm Ryan wrote:
> Yes, but I want the constraints to be passed around as data before  
> being applied. I'm working towards adding a feature to the  
> "generic_sets" library so that you can specify a bunch of constraints  
> that are applied to every element of the set. 

Yes, I often thought I need something like this.  And I understand what you
mean with 

> the handling of unbound variables is always awkward,

I would like to use constraint programming for problems where a solution is
not a particular assignment to the variables but the final set of
constraints on the (possibly unassigned) variables.  Traditionally, you
simply post constraints and then they are "lost" in the system - no way to
get them out again (not speaking of the processed, optimized set of
constraints after, e.g., propagation).

My solution here is to keep track of the posted constraints externally.
When the algorithm finds a solution (again, not necessarily a full
assignment but a constraint satisfaction problem for which there are valid
assignments) then the stored constraint set is manually post-processed and
returned.  Double work.

Please tell me about your progress.  I did my own homebrewn solutions and
sometimes had to resort to dirty tricks.  Keep on posting your questions.

Good luck!


Ulrich Scholz            

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Received on Thu Mar 29 2007 - 09:55:00 CEST

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