Module io.jenetics.ext
Package io.jenetics.ext.moea

Interface Vec<T>

Type Parameters:
T - the underlying array type, like int[] or double[]
All Superinterfaces:
Comparable<Vec<T>>
public interface Vec<T> extends Comparable<Vec<T>>
The Vec interface represents the fitness result of a multi-objective fitness function. It also defines a set of static factory methods which allows you to create Vec instance from a given int[], long[] or double[] array. 
final Vec<double[]> point2D = Vec.of(0.1, 5.4);
final Vec<int[]> point3D = Vec.of(1, 2, 3);
The underlying array is just wrapped and not copied. This means you can change the values of the Vec once it is created, Not copying the underlying array is done for performance reason. Changing the Vec data is, of course, never a good idea.
Since:
4.1
Version:
4.1
See Also:
Implementation Note:
Although the Vec interface extends the Comparable interface, it violates its general contract. It only implements the pareto dominance relation, which defines a partial order. So, trying to sort a list of Vec objects, might lead to an exception (thrown by the sorting method) at runtime.

  • Method Summary

    Modifier and Type
    Method
    Description
    ElementComparator<T>
    comparator()
    Return the comparator for comparing the elements of this MO vector.
    default int
    compare(Vec<T> other, int index)
    Compares the this vector with the other at the given component index.
    default int
    compareTo(Vec<T> other)
    The default implementation uses the dominance(Vec) function for defining a partial order of two vectors.
    T
    data()
    Return the underlying data structure.
    ElementDistance<T>
    distance()
    Return a function which calculates the element distance of a vector at a given element index.
    default double
    distance(Vec<T> other, int index)
    Calculates the distance between two vector elements at the given index.
    Comparator<T>
    dominance()
    Return the comparator which defines the (Pareto) dominance measure.
    static int
    dominance(double[] u, double[] v)
    Calculates the Pareto Dominance of the two vectors u and v.
    static int
    dominance(int[] u, int[] v)
    Calculates the Pareto Dominance of the two vectors u and v.
    static int
    dominance(long[] u, long[] v)
    Calculates the Pareto Dominance of the two vectors u and v.
    static <C extends Comparable<? super C>>
    int
    dominance(C[] u, C[] v)
    Calculates the Pareto Dominance of the two vectors u and v.
    default int
    dominance(Vec<T> other)
    Calculates the Pareto Dominance of vector value() and other.
    static <T> int
    dominance(T[] u, T[] v, Comparator<? super T> comparator)
    Calculates the Pareto Dominance of the two vectors u and v.
    int
    length()
    Return the number of vector elements.
    static Vec<double[]>
    of(double... array)
    Wraps the given array into a Vec object.
    static Vec<int[]>
    of(int... array)
    Wraps the given array into a Vec object.
    static Vec<long[]>
    of(long... array)
    Wraps the given array into a Vec object.
    static <C extends Comparable<? super C>>
    Vec<C[]>
    of(C[] array)
    Wraps the given array into a Vec object.
    static <C extends Comparable<? super C>>
    Vec<C[]>
    of(C[] array, ElementDistance<C[]> distance)
    Wraps the given array into a Vec object.
    static <T> Vec<T[]>
    of(T[] array, Comparator<? super T> comparator, ElementDistance<T[]> distance)
    Wraps the given array into a Vec object.

  • Method Details

    • data

      T data()
      Return the underlying data structure.
      Returns:
      the underlying data structure

    • length

      int length()
      Return the number of vector elements.
      Returns:
      the number of vector elements

    • comparator

      ElementComparator<T> comparator()
      Return the comparator for comparing the elements of this MO vector.
      Returns:
      the comparator for comparing the elements of this MO vector

    • distance

      ElementDistance<T> distance()
      Return a function which calculates the element distance of a vector at a given element index.
      Returns:
      a function which calculates the element distance of a vector at a given element index

    • dominance

      Comparator<T> dominance()
      Return the comparator which defines the (Pareto) dominance measure.
      Returns:
      the comparator which defines the (Pareto) dominance measure

    • compare

      default int compare(Vec<T> other, int index)
      Compares the this vector with the other at the given component index.
      Parameters:
      other - the other vector
      index - the component index
      Returns:
      a negative integer, zero, or a positive integer as this[index] is less than, equal to, or greater than other[index]
      Throws:
      NullPointerException - if the other object is null
      IllegalArgumentException - if the index is out of the valid range [0, length())

    • distance

      default double distance(Vec<T> other, int index)
      Calculates the distance between two vector elements at the given index.
      Parameters:
      other - the second vector
      index - the vector element index
      Returns:
      the distance between two vector elements
      Throws:
      NullPointerException - if the other vector is null
      IllegalArgumentException - if the index is out of the valid range [0, length())

    • dominance

      default int dominance(Vec<T> other)
      Calculates the Pareto Dominance of vector value() and other.
      Parameters:
      other - the other vector
      Returns:
      1 if value() ≻ other, -1 if other ≻ value() and 0 otherwise
      Throws:
      NullPointerException - if the other vector is null

    • compareTo

      default int compareTo(Vec<T> other)
      The default implementation uses the dominance(Vec) function for defining a partial order of two vectors.
      Specified by:
      compareTo in interface Comparable<T>
      Parameters:
      other - the other vector
      Returns:
      1 if value() ≻ other, -1 if other ≻ value() and 0 otherwise
      Throws:
      NullPointerException - if the other vector is null

    • dominance

      static <C extends Comparable<? super C>> int dominance(C[] u, C[] v)
      Calculates the Pareto Dominance of the two vectors u and v.
      Type Parameters:
      C - the element type of vector u and v
      Parameters:
      u - the first vector
      v - the second vector
      Returns:
      1 if u ≻ v, -1 if v ≻ u and 0 otherwise
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if u.length != v.length
      See Also:

    • dominance

      static <T> int dominance(T[] u, T[] v, Comparator<? super T> comparator)
      Calculates the Pareto Dominance of the two vectors u and v.
      Type Parameters:
      T - the element type of vector u and v
      Parameters:
      u - the first vector
      v - the second vector
      comparator - the element comparator which is used for calculating the dominance
      Returns:
      1 if u ≻ v, -1 if v ≻ u and 0 otherwise
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if u.length != v.length
      See Also:

    • dominance

      static int dominance(int[] u, int[] v)
      Calculates the Pareto Dominance of the two vectors u and v.
      Parameters:
      u - the first vector
      v - the second vector
      Returns:
      1 if u ≻ v, -1 if v ≻ u and 0 otherwise
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if u.length != v.length
      See Also:

    • dominance

      static int dominance(long[] u, long[] v)
      Calculates the Pareto Dominance of the two vectors u and v.
      Parameters:
      u - the first vector
      v - the second vector
      Returns:
      1 if u ≻ v, -1 if v ≻ u and 0 otherwise
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if u.length != v.length
      See Also:

    • dominance

      static int dominance(double[] u, double[] v)
      Calculates the Pareto Dominance of the two vectors u and v.
      Parameters:
      u - the first vector
      v - the second vector
      Returns:
      1 if u ≻ v, -1 if v ≻ u and 0 otherwise
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if u.length != v.length
      See Also:

    • of

      static <C extends Comparable<? super C>> Vec<C[]> of(C[] array)
      Wraps the given array into a Vec object.
      Type Parameters:
      C - the array element type
      Parameters:
      array - the wrapped array
      Returns:
      the given array wrapped into a Vec object.
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if the array length is zero

    • of

      static <C extends Comparable<? super C>> Vec<C[]> of(C[] array, ElementDistance<C[]> distance)
      Wraps the given array into a Vec object.
      Type Parameters:
      C - the array element type
      Parameters:
      array - the wrapped array
      distance - the array element distance measure
      Returns:
      the given array wrapped into a Vec object.
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if the array length is zero

    • of

      static <T> Vec<T[]> of(T[] array, Comparator<? super T> comparator, ElementDistance<T[]> distance)
      Wraps the given array into a Vec object.
      Type Parameters:
      T - the array element type
      Parameters:
      array - the wrapped array
      comparator - the (natural order) comparator of the array elements
      distance - the distance function between two vector elements
      Returns:
      the given array wrapped into a Vec object.
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if the array length is zero

    • of

      static Vec<int[]> of(int... array)
      Wraps the given array into a Vec object.
      Parameters:
      array - the wrapped array
      Returns:
      the given array wrapped into a Vec object.
      Throws:
      NullPointerException - if the given array is null
      IllegalArgumentException - if the array length is zero

    • of

      static Vec<long[]> of(long... array)
      Wraps the given array into a Vec object.
      Parameters:
      array - the wrapped array
      Returns:
      the given array wrapped into a Vec object.
      Throws:
      NullPointerException - if the given array is null
      IllegalArgumentException - if the array length is zero

    • of

      static Vec<double[]> of(double... array)
      Wraps the given array into a Vec object.
      Parameters:
      array - the wrapped array
      Returns:
      the given array wrapped into a Vec object.
      Throws:
      NullPointerException - if the given array is null
      IllegalArgumentException - if the array length is zero