Module org.cicirello.chips_n_salsa

Package org.cicirello.search.problems.scheduling

Class WeightedLateness

java.lang.Object

org.cicirello.search.problems.scheduling.WeightedLateness

All Implemented Interfaces:

IntegerCostOptimizationProblem<Permutation>, Problem<Permutation>, SingleMachineSchedulingProblem

public final class WeightedLateness
extends Object
implements SingleMachineSchedulingProblem

Implements the scheduling cost function known as weighted lateness. The lateness L[j] of job j is: L[j] = C[j] - d[j], where C[j] is the time it is completed by the machine, and d[j] is its due date. The weighted lateness cost function is the weighted sum over the jobs of: w[j]L[j], where w[j] is job j's weight. Note that the lateness of a job can be negative if the job is completed early, so this cost function can evaluate to a negative value.

Constructor Summary

Constructors

Constructor	Description
WeightedLateness(SingleMachineSchedulingProblemData instanceData)	Constructs a single machine scheduling problem for minimizing weighted lateness.

Method Summary

Modifier and Type	Method	Description
int	cost(Permutation candidate)	Computes the cost of a candidate solution to the problem instance.
SingleMachineSchedulingProblemData	getInstanceData()	Gets an object that encapsulates the data describing the scheduling problem instance, such as number of jobs, and the characteristics of the jobs, such as processing times, setup times, due dates, weights, etc.
int	value(Permutation candidate)	Computes the value of the candidate solution within the usual constraints and interpretation of the problem.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.cicirello.search.problems.IntegerCostOptimizationProblem

costAsDouble, getSolutionCostPair, isMinCost, minCost

Constructor Details

WeightedLateness

public WeightedLateness(SingleMachineSchedulingProblemData instanceData)

Constructs a single machine scheduling problem for minimizing weighted lateness.

Parameters:

instanceData - An encapsulation of the job characteristics, such as processing times, etc.

Throws:

IllegalArgumentException - if instanceData.hasDueDates() returns false.

Method Details

getInstanceData

public SingleMachineSchedulingProblemData getInstanceData()

Description copied from interface: SingleMachineSchedulingProblem

Gets an object that encapsulates the data describing the scheduling problem instance, such as number of jobs, and the characteristics of the jobs, such as processing times, setup times, due dates, weights, etc.

Specified by:

getInstanceData in interface SingleMachineSchedulingProblem

Returns:

an encapsulation of the data describing the scheduling problem instance

cost

public int cost(Permutation candidate)

Description copied from interface: IntegerCostOptimizationProblem

Computes the cost of a candidate solution to the problem instance. The lower the cost, the more optimal the candidate solution.

Specified by:

cost in interface IntegerCostOptimizationProblem<Permutation>

Parameters:

candidate - The candidate solution to evaluate.

Returns:

The cost of the candidate solution. Lower cost means better solution.

value

public int value(Permutation candidate)

Description copied from interface: IntegerCostOptimizationProblem

Computes the value of the candidate solution within the usual constraints and interpretation of the problem.

Specified by:

value in interface IntegerCostOptimizationProblem<Permutation>

Parameters:

candidate - The candidate solution to evaluate.

Returns:

The actual optimization value of the candidate solution.