org.ranksys.core.util.sampling

Class WeightedSampling<T>

java.lang.Object

org.ranksys.core.util.sampling.WeightedSampling<T>

Type Parameters:

T - type of sampled objects

public class WeightedSampling<T>
extends Object

Weighted sampling with and without replacement.

Author:

Saúl Vargas (Saul.Vargas@mendeley.com)

Constructor Summary

Constructors

Constructor and Description
WeightedSampling(Stream<T> elems, ToDoubleFunction<T> value, boolean withReplacement) Constructor
WeightedSampling(Stream<T> elems, ToDoubleFunction<T> value, boolean withReplacement, long seed) Constructor.
WeightedSampling(Stream<T> elems, ToDoubleFunction<T> value, boolean withReplacement, Random rnd) Constructor.

Method Summary

Modifier and Type	Method and Description
T	sample() Sample an element.
Stream<T>	sample(int k) Sample k elements.

Methods inherited from class java.lang.Object

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

Constructor Detail

WeightedSampling

public WeightedSampling(Stream<T> elems,
                        ToDoubleFunction<T> value,
                        boolean withReplacement)

Constructor

Parameters:

elems - stream of element to sample from

value - sampling weight function

withReplacement - if true selection with replacement, without otherwise

WeightedSampling

public WeightedSampling(Stream<T> elems,
                        ToDoubleFunction<T> value,
                        boolean withReplacement,
                        long seed)

Constructor.

Parameters:

elems - stream of element to sample from

value - sampling weight function

withReplacement - if true selection with replacement, without otherwise

seed - seed to Random constructor

WeightedSampling

public WeightedSampling(Stream<T> elems,
                        ToDoubleFunction<T> value,
                        boolean withReplacement,
                        Random rnd)

Constructor.

Parameters:

elems - stream of element to sample from

value - sampling weight function

withReplacement - if true selection with replacement, without otherwise

rnd - random

Method Detail

sample

public Stream<T> sample(int k)

Sample k elements.

Parameters:

k - (maximum) number of element to sample

Returns:

sampled elements

sample

public T sample()

Sample an element.

Returns:

sampled element