fd_minimize(Goal, X) repeatedly calls Goal to find a value that minimizes the variable X. Goal is a Prolog goal that should instantiate X, a common case being the use of fd_labeling/2 (section 9.9.1). This predicate uses a branch-and-bound algorithm with restart: each time call(Goal) succeeds the computation restarts with a new constraint X #< V where V is the value of X at the end of the last call of Goal. When a failure occurs (either because there are no remaining choice-points for Goal or because the added constraint is inconsistent with the rest of the store) the last solution is recomputed since it is optimal.
fd_maximize(Goal, X) is similar to fd_minimize/2 but X is maximized.
|Goal is a variable||instantiation_error|
|Goal is neither a variable nor a callable term||type_error(callable, Goal)|
|The predicate indicator Pred of Goal does not correspond to an existing procedure and the value of the unknown Prolog flag is error (section 8.22.1)||existence_error(procedure, Pred)|
|X is neither a variable nor an FD variable nor an integer||type_error(fd_variable, X)|
GNU Prolog predicates.