All Implemented Interfaces:
ConstructiveHeuristic<Permutation>

public final class ATCS extends WeightedShortestProcessingTime

This is an implementation of the ATCS (Apparent Tardiness Cost with Setups) heuristic. ATCS is defined as: h(j) = (w[j]/p[j]) exp( -max(0,d[j] - T - p[j]) / (k1 p̄) ) exp( -s[i][j] / (k2 s̄)), where w[j] is the weight of job j, p[j] is its processing time, d[j] is the job's due date, T is the current time, and s[i][j] is any setup time of the job if it follows job i. The k1 and k2 are parameters that can be tuned based on problem instance characteristics, p̄ is the average processing time of all jobs, and s̄ is the average setup time of all jobs. The p̄ and s̄ are computed once at the start. For a version of the heuristic that dynamically updates these, see the DynamicATCS class.

The constant MIN_H defines the minimum value the heuristic will return, preventing h(j)=0 in support of stochastic sampling algorithms for which h(j)=0 is problematic. This implementation returns max( MIN_H, h(j)), where MIN_H is a small non-zero value.

  • Field Details

    • MIN_H

      public static final double MIN_H
      The minimum heuristic value. If the heuristic value as calculated is lower than MIN_H, then MIN_H is used as the heuristic value. The reason is related to the primary purpose of the constructive heuristics in the library: heuristic guidance for stochastic sampling algorithms, which assume positive heuristic values (e.g., an h of 0 would be problematic).
      See Also:
  • Constructor Details

    • ATCS

      public ATCS(SingleMachineSchedulingProblem problem, double k1, double k2)
      Constructs an ATCS heuristic.
      Parameters:
      problem - The instance of a scheduling problem that is the target of the heuristic.
      k1 - A parameter to the heuristic, which must be positive.
      k2 - A parameter to the heuristic, which must be positive.
      Throws:
      IllegalArgumentException - if problem.hasDueDates() returns false.
      IllegalArgumentException - if k ≤ 0.0.
    • ATCS

      public ATCS(SingleMachineSchedulingProblem problem)
      Constructs an ATCS heuristic. Sets the values of k1 and k2 according to the procedure described by the authors of the ATCS heuristic.
      Parameters:
      problem - The instance of a scheduling problem that is the target of the heuristic.
      Throws:
      IllegalArgumentException - if problem.hasDueDates() returns false.
  • Method Details