Templates
Description
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 8.9.1). 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.
Errors
| 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 7.22.1) | existence_error(procedure, Pred) | |
| X is neither a variable nor an FD variable nor an integer | type_error(fd_variable, X) | |
Portability
GNU Prolog predicates.