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
Constructors Constructor Description WeightedSquaredTardiness(SingleMachineSchedulingProblemData instanceData)
Constructs a single machine scheduling problem for minimizing weighted squared tardiness.

Method Summary
All Methods Instance Methods Concrete Methods 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
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
getSolutionCostPair, isMinCost




Constructor Detail

WeightedSquaredTardiness
public WeightedSquaredTardiness(SingleMachineSchedulingProblemData instanceData)
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 Detail

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 interfaceSingleMachineSchedulingProblem
 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 interfaceIntegerCostOptimizationProblem<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 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.

