Module constraints

Expand description

Defines the constraints that Pumpkin provides out of the box which can be added to the Solver.

A constraint is a relation over variables. In the solver, constraints are enforced through propagators, and therefore constraints can be viewed as a collection of propagators.

§Example

let mut solver = Solver::default();

let a = solver.new_bounded_integer(0, 3);
let b = solver.new_bounded_integer(0, 3);

// All constraints require a constraint tag.
let constraint_tag = solver.new_constraint_tag();

solver
    .add_constraint(constraints::equals([a, b], 0, constraint_tag))
    .post();

§Note

At the moment, the API for posting propagators is not yet publicly accessible as it is unstable. Consumers of the Pumpkin library can therefore only define constraints by decomposing them into the constraints that are predefined in the library. Once the propagator API is stabilized, it will become part of the public API.

Structs§

ConstraintPoster: A structure which is responsible for adding the created Constraints to the Solver. For an example on how to use this, see crate::constraints.

Traits§

Constraint: A Constraint is a relation over variables. It disqualifies certain partial assignments of making it into a solution of the problem.
NegatableConstraint: A Constraint which has a well-defined negation.

Functions§

absolute: Creates the Constraint |signed| = absolute.
all_different: Creates the Constraint that enforces that all the given variables are distinct.
binary_equals: Creates the NegatableConstraint lhs = rhs.
binary_greater_than: Creates the NegatableConstraint lhs > rhs.
binary_greater_than_or_equals: Creates the NegatableConstraint lhs >= rhs.
binary_less_than: Creates the NegatableConstraint lhs < rhs.
binary_less_than_or_equals: Creates the NegatableConstraint lhs <= rhs.
binary_not_equals: Creates the NegatableConstraint lhs != rhs.
boolean_equals: Creates the Constraint \sum weights_i * bools_i == rhs.
boolean_less_than_or_equals: Creates the Constraint \sum weights_i * bools_i <= rhs.
clause: Creates the NegatableConstraint \/ literal
conjunction: Creates the NegatableConstraint /\ literal
cumulative: Creates the Cumulative Constraint.
cumulative_with_options: Creates the Cumulative constraint with the provided CumulativeOptions.
disjunctive_strict: Creates the Disjunctive Constraint (also called the NoOverlap Constraint or the Unary Resource Constraint).
division: Creates the Constraint numerator / denominator = rhs.
element: Creates the element Constraint which states that array[index] = rhs.
equals: Creates the NegatableConstraint \sum terms_i = rhs.
greater_than: Create the NegatableConstraint \sum terms_i > rhs.
greater_than_or_equals: Create the NegatableConstraint \sum terms_i >= rhs.
less_than: Create the NegatableConstraint \sum terms_i < rhs.
less_than_or_equals: Create the NegatableConstraint \sum terms_i <= rhs.
maximum: Creates the Constraint max(array) = m.
minimum: Creates the Constraint min(array) = m.
negative_table: Create a negative table constraint over the variables xs.
not_equals: Create the NegatableConstraint \sum terms_i != rhs.
plus: Creates the Constraint a + b = c.
table: Create a table constraint over the variables xs.
times: Creates the Constraint a * b = c.