Struct vrp_core::models::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 in order to select better one: for example, given the same amount of assigned jobs, prefer less tours used instead of total solution cost.

A local objective defines how 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 amount of tours served, maximize 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’ demand, time limitations for vehicles/jobs, etc.

Implementations

impl GoalContext

pub fn new(features: &[Feature], goal: Goal) -> Result<Self, GenericError>

Creates a new instance of GoalContext with features specified using information about hierarchy of objectives.

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

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

Creates a new instance of GoalContext with given feature constraints.

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

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 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 together having 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.

Trait Implementations

impl Clone for GoalContext

fn clone(&self) -> GoalContext

Returns a copy 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 Default for GoalContext

fn default() -> GoalContext

Returns the “default value” for a type.

impl MultiObjective 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.

fn fitness<'a>( &'a self, solution: &'a Self::Solution ) -> Box<dyn Iterator<Item = f64> + 'a>

An objective fitness values for given solution.

fn get_order( &self, a: &Self::Solution, b: &Self::Solution, idx: usize ) -> Result<Ordering, GenericError>

Get solution order for individual objective.

fn get_distance( &self, a: &Self::Solution, b: &Self::Solution, idx: usize ) -> Result<f64, GenericError>

Gets solution distance for individual objective.

fn size(&self) -> usize

Returns total number of inner objectives.

impl Shuffled for GoalContext

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

Returns a new instance of GoalContext with shuffled objectives.

impl HeuristicObjective for GoalContext