10.55.5 Limitations

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 are given maximally wide bounded domains 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. 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, and seq_search.
• The FlatZinc specification describes several exploration strategies. Currently, the only recognized exploration strategies are complete and fail.
• Variables not included in any solve or is_defined_var annotation are labeled with a default first-fail domain splitting heuristic. This corresponds to labeling/2 of library(clpfd) with the option list [ff,bisect].
• 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 by the FlatZinc interpreter. Any other constraint annotation is ignored.

Variable annotations

The following variable annotations are recognized. Any other variable annotation is ignored:

output_var   since release 4.2

the variable may be written on the current output stream.

output_array   since release 4.2

the variable array may be written on the current output stream.

is_defined_var

the variable will not be considered in any default labeling (such as when the search annotations do not include all variables)