documents/tutorial/fdintro.tex

338 \item        whose capacity constraints are:
341 \item        red   has capacity 3
342 \item        blue  has capacity 1
343 \item 	     green has capacity 4
364 \item and certain bin types have capacity constraint for certain
394 To represent a bin, with its colour, capacity and contents we use
397 :- local struct(bin(colour,capacity,contents:contents))
483 constrain_bin(bin\{colour:Col,capacity:Cap,contents:C\}) :-
492 The colour capacity constraint relates the colour of the bin to its
493 capacity.  It uses generalised propagation to apply
498 	capacity(Col,Cap) infers ac.
500 capacity(blue, 1).
501 capacity(green,4).
502 capacity(red,  3).
509 \paragraph{capacity\_constraint}
510 The capacity constraint states:
515 their sum does not exceed the capacity of the bin,
571 Like the capacity constraint, the relation between the colour and
572 capacity ($WCap$ is expressed using generalised propagation to enforce
574 exceed the capacity:
581 colour_wood_cap(blue, Cap) :- capacity(blue, Cap).
587 This model artificially introduces a capacity of blue bins for
588 wood items (set simply at its maximum capacity for all items).
678 The first requirement is to ensure the capacity variable has a finite
689 invoking the capacity predicate.  If, however, the colour $Col$ is a
695     ( nonvar(Col) -> capacity(Col,Cap) ;
701 If the required capacity (i.e. the minimum value in the domain of $Cap$)
703 If, moreover, the required capacity is more than 3, then the colour must
705 If the required capacity is either 2 or 3, then any change to the $Col$
709 colour for each capacity, as well as vice versa, it suffices to call the
710 capacity predicate as soon as either variable is instantiated.
711 If, however the minimum capacity is still 1, then the col\_cap\_cons
714 capacity increases \verb0Cap->min0:
724             suspend(capacity(Col, Cap), 3, (Col, Cap)->inst)