10.39.1 Notes

Domain variables

Only variables with finite integer domains are supported. This includes boolean variables which are considered finite integer domain variables with the domain 0..1. Domain variables declared to be of type var int are initially given the finite integer domain inf..sup, and constrained to -2^27..2^27 before any search is performed on them, as well as before certain constraints that demand bounded domains are posted on them.

Ground set values

Although set variables are not supported, ground set values are supported. For example, the MiniZinc global constraint sum_pred/4 takes as second argument an array of such ground set values.

Solve annotations

• The solve annotations currently recognized are bool_search, int_search, labelling_ff, and seq_search.
• The FlatZinc specification describes several exploration strategies. Currently, the only recognized exploration strategies are complete and fail.
• When no solve annotation is given, a default leftmost indomain heuristic is used on all problem variables (excluding those that have a var_is_introduced annotation; see below). This corresponds to labeling/2 of library(clpfd) with the option list [leftmost, step, up].
• The choice method indomain_random as described in the FlatZinc specification uses random_member/2 of library(random). The random generator of SICStus is initialized using the same seed on each start up, meaning that the same sequence will be tried for indomain_random on each start up. This behavior can be changed by setting a different random seed using setrand/1 of library(random).

Constraint annotations

Constraint annotations of the form domain, bounds, and value are recognized in relevant FlatZinc-to-library(clpfd) constraint translations. Any other constraint annotation is ignored.

Variable annotations

The following variable annotations are recognized:

• output_var: the variable may be written on the current output stream.
• output_array: the variable array may be written on the current output stream.
• var_is_introduced: the variable will not be considered in any default labeling (such as when no search annotation is given or when the labelling_ff search annotation is given).

Any other variable annotation is ignored.