Module org.cicirello.chips_n_salsa
Class WeightedSquaredTardiness
java.lang.Object
org.cicirello.search.problems.scheduling.WeightedSquaredTardiness
 All Implemented Interfaces:
IntegerCostOptimizationProblem<Permutation>
,Problem<Permutation>
,SingleMachineSchedulingProblem
public final class WeightedSquaredTardiness
extends Object
implements SingleMachineSchedulingProblem
Implements the scheduling cost function known as weighted squared tardiness. 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 tardiness of job j is: T[j] = max(0, L[j]). That is, although lateness can be
negative, tardiness is never negative (i.e., no reward for a job completing early). The weighted
squared tardiness cost function is the weighted sum of the squares of the tardiness of the jobs
of, i.e., the sum of w[j]T[j]^{2} over all jobs j, where w[j] is job j's weight.

Constructor Summary
ConstructorDescriptionWeightedSquaredTardiness
(SingleMachineSchedulingProblemData instanceData) Constructs a single machine scheduling problem for minimizing weighted squared tardiness. 
Method Summary
Modifier and TypeMethodDescriptionint
cost
(Permutation candidate) Computes the cost of a candidate solution to the problem instance.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
minCost()
A lower bound on the minimum theoretical cost across all possible solutions to the problem instance, where lower cost implies better solution.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

Constructor Details

WeightedSquaredTardiness
Constructs a single machine scheduling problem for minimizing weighted squared tardiness. Parameters:
instanceData
 An encapsulation of the job characteristics, such as processing times, etc. Throws:
IllegalArgumentException
 if instanceData.hasDueDates() returns false.


Method Details

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 interfaceSingleMachineSchedulingProblem
 Returns:
 an encapsulation of the data describing the scheduling problem instance

cost
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 interfaceIntegerCostOptimizationProblem<Permutation>
 Parameters:
candidate
 The candidate solution to evaluate. Returns:
 The cost of the candidate solution. Lower cost means better solution.

value
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 interfaceIntegerCostOptimizationProblem<Permutation>
 Parameters:
candidate
 The candidate solution to evaluate. Returns:
 The actual optimization value of the candidate solution.

minCost
public int minCost()Description copied from interface:IntegerCostOptimizationProblem
A lower bound on the minimum theoretical cost across all possible solutions to the problem instance, where lower cost implies better solution. The default implementation returns Integer.MIN_VALUE. Specified by:
minCost
in interfaceIntegerCostOptimizationProblem<Permutation>
 Returns:
 A lower bound on the minimum theoretical cost of the problem instance.
