Re: [eclipse-clp-users] Why the minimize is halting in each solution?

On 22/06/2013 15:32, Claudio Cesar de Sá wrote:
> Sergii
>
> Thanks your solution, surely it is simpler and shorter, but in my
> solution in predicate  member(X_var , [list the templates = option])
> should be works like:
> ?- member(X, [[1, 1, 0], [0, 1, 1]]).
> X = [1, 1, 0]
> Yes (0.00s cpu, solution 1, maybe more)
> X = [0, 1, 1]
> Yes (0.01s cpu, solution 2)
>
> where each solution is a branch in the tree search.
> These are choices points for the search.
>
> Why is it not working as expected?


If you want to optimize, then all your search must be done _inside_
the minimize/2 or bb_min/3 predicate.  As Sergii already said:

> In your model your should not have any predicates like `member`, only
> constraints. Basically, your model should not leave any Prolog choice
> points.

This is the basic rule for a constraint program:
1. first deterministic constraint setup
2. then nondeterministic search (possibly with b&b)


So, move your member/2 call inside minimize/2:

       minimize((
               member(L_X , All_contiguities),
               search(L_X,0,first_fail,indomain,complete,[])
          ), Zneg).

In your code, you don't actually need search/6, because L_X is already
fully instantiated.  It is a bit strange to precompute a list of all
possibilities, and then search over it.  It would be more elegant to
nondeterministically generate the different combinations directly and
do this instead of the member/2.


-- Joachim