Package tk.airshipcraft.commonlib.utils.math

Class BiasedRandomPicker<E>

java.lang.Object
tk.airshipcraft.commonlib.utils.math.BiasedRandomPicker<E>
Type Parameters:
E - The type of object that can be picked.
public class BiasedRandomPicker<E> extends Object
This class allows for random selection of objects based on assigned probabilities. It is particularly useful when objects need to be picked with non-uniform chances, enabling the creation of biased random outcomes according to specified weights.
Since:
2023-04-03
Version:
1.0.0
Author:
notzune

  • Constructor Summary

    Constructors
    Constructor
    Description
    BiasedRandomPicker(Map<E,Double> chances)
    Constructs a BiasedRandomPicker with a map of objects and their associated probabilities.

  • Method Summary

    Modifier and Type
    Method
    Description
    double
    getChance(E e)
    Retrieves the probability of an object being picked by this BiasedRandomPicker instance.
    E
    getRandom()
    Randomly selects an object from the pool, considering the assigned chances.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • BiasedRandomPicker

      public BiasedRandomPicker(Map<E,Double> chances)
      Constructs a BiasedRandomPicker with a map of objects and their associated probabilities. The total sum of all provided chances must equal 1, within a tolerance of 10^(-6). A chance of 0 indicates that the object will never be picked, while a chance of 1 indicates certainty.
      Parameters:
      chances - A map where each key is an object to pick and each value is the chance of picking that object.
      Throws:
      IllegalArgumentException - If the provided map is null, contains null values, or if the sum of chances is not 1.

  • Method Details

    • getRandom

      public E getRandom()
      Randomly selects an object from the pool, considering the assigned chances. If the configuration is malformed, there is an extremely low probability that this method may return null, but such a case is highly unlikely (less than 10^(-120)).
      Returns:
      A randomly picked element based on the biased chances.

    • getChance

      public double getChance(E e)
      Retrieves the probability of an object being picked by this BiasedRandomPicker instance. If the object was not assigned an explicit chance, a default of 0.0 is returned.
      Parameters:
      e - The object for which to retrieve the selection chance.
      Returns:
      The probability of the object being picked.