Package org.apache.commons.rng.sampling

Class DiscreteProbabilityCollectionSampler<T>

java.lang.Object
org.apache.commons.rng.sampling.DiscreteProbabilityCollectionSampler<T>
Type Parameters:
T - Type of items in the collection.
public class DiscreteProbabilityCollectionSampler<T>
extends java.lang.Object
Sampling from a collection of items with user-defined probabilities. Note that if all unique items are assigned the same probability, it is much more efficient to use CollectionSampler.

Sampling uses UniformRandomProvider.nextDouble().

Since:
1.1

  • Constructor Summary

    Constructors 
    Constructor Description
    DiscreteProbabilityCollectionSampler​(UniformRandomProvider rng, java.util.List<T> collection, double[] probabilities)
    Creates a sampler.
    DiscreteProbabilityCollectionSampler​(UniformRandomProvider rng, java.util.Map<T,​java.lang.Double> collection)
    Creates a sampler.

  • Method Summary

    Modifier and Type Method Description
    T sample()
    Picks one of the items from the collection passed to the constructor.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • DiscreteProbabilityCollectionSampler

      public DiscreteProbabilityCollectionSampler​(UniformRandomProvider rng, java.util.Map<T,​java.lang.Double> collection)
      Creates a sampler.
      Parameters:
      rng - Generator of uniformly distributed random numbers.
      collection - Collection to be sampled, with the probabilities associated to each of its items. A (shallow) copy of the items will be stored in the created instance. The probabilities must be non-negative, but zero values are allowed and their sum does not have to equal one (input will be normalized to make the probabilities sum to one).
      Throws:
      java.lang.IllegalArgumentException - if collection is empty, a probability is negative, infinite or NaN, or the sum of all probabilities is not strictly positive.

    • DiscreteProbabilityCollectionSampler

      public DiscreteProbabilityCollectionSampler​(UniformRandomProvider rng, java.util.List<T> collection, double[] probabilities)
      Creates a sampler.
      Parameters:
      rng - Generator of uniformly distributed random numbers.
      collection - Collection to be sampled. A (shallow) copy of the items will be stored in the created instance.
      probabilities - Probability associated to each item of the collection. The probabilities must be non-negative, but zero values are allowed and their sum does not have to equal one (input will be normalized to make the probabilities sum to one).
      Throws:
      java.lang.IllegalArgumentException - if collection is empty or a probability is negative, infinite or NaN, or if the number of items in the collection is not equal to the number of provided probabilities.

  • Method Details

    • sample

      public T sample()
      Picks one of the items from the collection passed to the constructor.
      Returns:
      a random sample.