4.2.2. Annotations¶
These annotations control evaluation and solving behaviour.
4.2.2.1. General annotations¶
Parameters¶
annotation add_to_output
Declare that the annotated variable should be added to the output of the model. This annotation only has an effect when the model does not have an output item.
annotation is_defined_var
Declare the annotated variable as being functionally defined. This annotation is introduced into FlatZinc code by the compiler.
annotation is_reverse_map
Declare that the annotated expression is used to map an expression back from FlatZinc to MiniZinc.
annotation maybe_partial
Declare that expression may have undefined result (to avoid warnings)
annotation mzn_break_here
With debug build of mzn2fzn, call MiniZinc::mzn_break_here when flattening this expression to make debugging easier. This annotation is ignored by the release build.
annotation mzn_check_var
Declare that the annotated variable is required for checking solutions.
annotation mzn_rhs_from_assignment
Used internally by the compiler *
annotation output_only
Declare that the annotated variable should be only used for output. This annotation can be used to define variables that are required for solution checkers, or that are necessary for the output item. The annotated variable must be par.
annotation output_var
Declare that the annotated variable should be printed by the solver. This annotation is introduced into FlatZinc code by the compiler.
annotation promise_total
Declare function as total, i.e. it does not put any constraints on its arguments.
annotation var_is_introduced
Declare a variable as being introduced by the compiler.
Functions and Predicates¶
annotation constraint_name(string: s)
Used to attach a name s to a constraint and its decomposition. String annotations on constraint keywords are re-written as constraint_name annotations *
annotation defines_var(var $t: c)
Declare variable: c as being functionally defined by the annotated constraint. This annotation is introduced into FlatZinc code by the compiler.
annotation doc_comment(string: s)
Document the function or variable declaration item with the string s .
annotation expression_name(string: s)
Used to attach a name s to an expression, this should also propagate to any sub-expressions or decomposition of the annotated expression. String annotations on expressions are re-written as expression_name annotations *
annotation mzn_check_enum_var(set of int)
Declare that the annotated variable is required for checking solutions and has an enum type.
annotation mzn_constraint_name(string)
Declare a name for the annotated constraint.
annotation mzn_expression_name(string)
Declare a name for the annotated expression.
annotation mzn_path(string: s)
Representation of the call-stack when the annotated item was introduced, as a string s . Can be used to uniquely identify variables and constraints across different compilations of a model that may have different names. This annotations is introduced into FlatZinc code by the compiler and is retained if –keep-paths argument is used.
annotation output_array(array [$u] of set of int: a)
Declare that the annotated array should be printed by the solver with the given index sets a . This annotation is introduced into FlatZinc code by the compiler.
4.2.2.2. Propagation strength annotations¶
annotation bounds
Annotate a constraint to use bounds propagation
annotation domain
Annotate a constraint to use domain propagation
4.2.2.3. Search annotations¶
Variable selection annotations¶
annotation anti_first_fail
Choose the variable with the largest domain
annotation dom_w_deg
Choose the variable with largest domain, divided by the number of attached constraints weighted by how often they have caused failure
annotation first_fail
Choose the variable with the smallest domain
annotation impact
Choose the variable with the highest impact so far during the search
annotation input_order
Search variables in the given order
annotation largest
Choose the variable with the largest value in its domain
annotation max_regret
Choose the variable with largest difference between the two smallest values in its domain
annotation most_constrained
Choose the variable with the smallest domain, breaking ties using the number of attached constraints
annotation occurrence
Choose the variable with the largest number of attached constraints
annotation smallest
Choose the variable with the smallest value in its domain
Value choice annotations¶
annotation indomain
Assign values in ascending order
annotation indomain_interval
If the domain consists of several contiguous intervals, reduce the domain to the first interval. Otherwise bisect the domain.
annotation indomain_max
Assign the largest value in the domain
annotation indomain_median
Assign the middle value in the domain
annotation indomain_middle
Assign the value in the domain closest to the mean of its current bounds
annotation indomain_min
Assign the smallest value in the domain
annotation indomain_random
Assign a random value from the domain
annotation indomain_reverse_split
Bisect the domain, excluding the lower half first
annotation indomain_split
Bisect the domain, excluding the upper half first
annotation indomain_split_random
Bisect the domain, randomly selecting which half to exclude first
annotation outdomain_max
Exclude the largest value from the domain
annotation outdomain_median
Exclude the middle value from the domain
annotation outdomain_min
Exclude the smallest value from the domain
annotation outdomain_random
Exclude a random value from the domain
Restart annotations¶
Functions and Predicates¶
annotation restart_constant(int: scale)
Restart after constant number of nodes scale
annotation restart_geometric(float: base, int: scale)
Restart with geometric sequence with parameters base and scale
annotation restart_linear(int: scale)
Restart with linear sequence scaled by scale
annotation restart_luby(int: scale)
Restart with Luby sequence scaled by scale
Other declarations¶
annotation bool_search(array [int] of var bool: x,
ann: select,
ann: choice,
ann: explore)
Specify search on variables x , with variable selection strategy select , value choice strategy choice , and exploration strategy explore .
annotation bool_search(array [int] of var bool: x,
ann: select,
ann: choice)
Specify search on variables x , with variable selection strategy select , and value choice strategy choice .
annotation float_search(array [int] of var float: x,
float: prec,
ann: select,
ann: choice,
ann: explore)
Specify search on variables x , with precision prec , variable selection strategy select , value choice strategy choice , and exploration strategy explore .
annotation float_search(array [int] of var float: x,
float: prec,
ann: select,
ann: choice)
Specify search on variables x , with precision prec , variable selection strategy select , and value choice strategy choice .
annotation int_search(array [int] of var int: x,
ann: select,
ann: choice,
ann: explore)
Specify search on variables x , with variable selection strategy select , value choice strategy choice , and exploration strategy explore .
annotation int_search(array [int] of var int: x,
ann: select,
ann: choice)
Specify search on variables x , with variable selection strategy select , and value choice strategy choice .
annotation seq_search(array [int] of ann: s)
Sequentially perform the searches specified in array s
annotation set_search(array [int] of var set of int: x,
ann: select,
ann: choice,
ann: explore)
Specify search on variables x , with variable selection strategy select , value choice strategy choice , and exploration strategy explore .
annotation set_search(array [int] of var set of int: x,
ann: select,
ann: choice)
Specify search on variables x , with variable selection strategy select , and value choice strategy choice .
4.2.2.4. Warm start annotations¶
To be put on the solve item, similar to search annotations. A variable can be mentioned several times and in different annotations but only one of the values is taken
Warm start annotations with optional values¶
The value arrays can contain <> elements (absent values). The following decompositions eliminate those elements because FlatZinc 1.6 does not support optionals.
annotation warm_start(array [int] of var bool: x,
array [int] of opt bool: v)
Specify warm start values v for an array of booleans x
annotation warm_start(array [int] of var int: x,
array [int] of opt int: v)
Specify warm start values v for an array of integers x
annotation warm_start(array [int] of var float: x,
array [int] of opt float: v)
Specify warm start values v for an array of floats x
annotation warm_start(array [int] of var set of int: x,
array [int] of opt set of int: v)
Specify warm start values v for an array of sets x
Other declarations¶
annotation warm_start(array [int] of var bool: x,
array [int] of bool: v)
Specify warm start values v for an array of booleans x
annotation warm_start(array [int] of var int: x, array [int] of int: v)
Specify warm start values v for an array of integers x
annotation warm_start(array [int] of var float: x,
array [int] of float: v)
Specify warm start values v for an array of floats x
annotation warm_start(array [int] of var set of int: x,
array [int] of set of int: v)
Specify warm start values v for an array of sets x
annotation warm_start_array(array [int] of ann: w)
Specify an array w of warm_start annotations or other warm_start_array annotations. Can be useful to keep the annotation order in FlatZinc for manual updating.
Note: if you have search annotations as well, put warm_starts into seq_search in order to have precedence between both, which may matter.