Struct GoalContext

pub struct GoalContext { /* private fields */ }

Defines Vehicle Routing Problem variant by global and local objectives: A global objective defines the way two VRP solutions are compared to select better one: for example, given the same number of assigned jobs, prefer fewer tours used instead of total solution cost.

A local objective defines how a single VRP solution is created/modified. It specifies hard constraints such as vehicle capacity, time windows, skills, etc. Also, it defines soft constraints which are used to guide search in preferred by global objective direction: reduce the number of tours served, maximize the total value of assigned jobs, etc.

Both, global and local objectives, are specified by individual features. In general, a Feature encapsulates a single VRP aspect, such as capacity constraint for job’s demand, time limitations for vehicles/jobs, etc.

Implementations

impl GoalContext

pub fn with_constraints<Iter>(&self, constraints: Iter) -> Self

where Iter: Iterator<Item = Arc<dyn FeatureConstraint>>,

Creates a new instance of GoalContext with given feature constraints.

pub fn constraints( &self, ) -> impl Iterator<Item = Arc<dyn FeatureConstraint>> + '_

Returns an iterator over internal feature constraints.

impl GoalContext

pub fn accept_insertion( &self, solution_ctx: &mut SolutionContext, route_index: usize, job: &Job, )

Accepts job insertion.

pub fn accept_route_state(&self, route_ctx: &mut RouteContext)

Accepts route state.

pub fn accept_solution_state(&self, solution_ctx: &mut SolutionContext)

Accepts solution state.

pub fn notify_failure( &self, solution_ctx: &mut SolutionContext, route_indices: &[usize], jobs: &[Job], ) -> bool

Notifies about a failed attempt to insert given jobs into given routes (indices). Returns true if failure is some attempt to handle failure was performed and retry can be performed.

pub fn merge(&self, source: Job, candidate: Job) -> Result<Job, ViolationCode>

Tries to merge two jobs taking into account common constraints. Returns a new job, if it is possible to merge them having a theoretically assignable job. Otherwise returns violation error code.

pub fn evaluate( &self, move_ctx: &MoveContext<'_>, ) -> Option<ConstraintViolation>

Evaluates feasibility of the refinement move.

pub fn estimate(&self, move_ctx: &MoveContext<'_>) -> InsertionCost

Estimates insertion cost (penalty) of the refinement move.

pub fn fitness<'a>( &'a self, solution: &'a InsertionContext, ) -> impl Iterator<Item = Float> + 'a

Calculates solution’s fitness.

Trait Implementations

impl Clone for GoalContext

fn clone(&self) -> GoalContext

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GoalContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl HeuristicObjective for GoalContext

type Solution = InsertionContext

The solution value type that we define the objective on.

fn total_order(&self, a: &Self::Solution, b: &Self::Solution) -> Ordering

An objective defines a total ordering between any two solution values.

impl Shuffled for GoalContext

fn get_shuffled(&self, random: &dyn Random) -> Self

Returns a new objective, potentially shuffled.