Module org.cicirello.chips_n_salsa
Package org.cicirello.search.problems

Class ForresterEtAl2008

java.lang.Object
org.cicirello.search.problems.ForresterEtAl2008
All Implemented Interfaces:
Splittable<Initializer<SingleReal>>, Initializer<SingleReal>, OptimizationProblem<SingleReal>, Problem<SingleReal>
public final class ForresterEtAl2008 extends Object implements OptimizationProblem<SingleReal>, Initializer<SingleReal>
A continuous function with a single suboptimal local minimum, and a single global minimum, and a 0 derivative inflexion point, defined for inputs x in [0.0, 1.0].

This minimization problem was introduced in:

  • Forrester, A.I.J.; Sóbester, A.; Keane, A.J. Appendix: Example Problems. In Engineering Design via Surrogate Modelling: A Practical Guide; John Wiley and Sons, Ltd, 2008; pp. 195–203. doi:10.1002/9780470770801.app1.

The lower fidelity variation is as defined https://www.sfu.ca/~ssurjano/forretal08.html.

  • Constructor Details

    • ForresterEtAl2008

      public ForresterEtAl2008()
      Constructs the original version of the ForresterEtAl2008 cost function.

    • ForresterEtAl2008

      public ForresterEtAl2008(boolean lowerFidelity)
      Constructs the ForresterEtAl2008 cost function.
      Parameters:
      lowerFidelity - - If false, constructs the original function. If true, constructs the lower fidelity version of the function.

  • Method Details

    • cost

      public double cost(SingleReal candidate)
      Description copied from interface: OptimizationProblem
      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 OptimizationProblem<SingleReal>
      Parameters:
      candidate - The candidate solution to evaluate.
      Returns:
      The cost of the candidate solution. Lower cost means better solution.

    • value

      public double value(SingleReal candidate)
      Description copied from interface: OptimizationProblem
      Computes the value of the candidate solution within the usual constraints and interpretation of the problem.
      Specified by:
      value in interface OptimizationProblem<SingleReal>
      Parameters:
      candidate - The candidate solution to evaluate.
      Returns:
      The actual optimization value of the candidate solution.

    • createCandidateSolution

      public SingleReal createCandidateSolution()
      Description copied from interface: Initializer
      Creates one candidate solution to a problem.
      Specified by:
      createCandidateSolution in interface Initializer<SingleReal>
      Returns:
      a candidate solution to a problem instance.

    • split

      public ForresterEtAl2008 split()
      Description copied from interface: Splittable
      Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms. The state of the object that is returned may or may not be identical to that of the original. Thus, this is a distinct concept from the functionality of the Copyable interface. Classes that implement this interface must ensure that the object returned performs the same functionality, and that it does not share any state data that would be either unsafe or inefficient for concurrent access by multiple threads. The split method is allowed to simply return the this reference, provided that it is both safe and efficient for multiple threads to share a single copy of the Splittable object. The intention is to provide a multithreaded search with the capability to provide spawned threads with their own distinct search operators. Such multithreaded algorithms can call the split method for each thread it spawns to generate a functionally identical copy of the operator, but with independent state.
      Specified by:
      split in interface Splittable<Initializer<SingleReal>>
      Returns:
      A functionally identical copy of the object, or a reference to this if it is both safe and efficient for multiple threads to share a single instance of this Splittable object.