Developer API

org.apache.spark.util.random

Class PoissonSampler<T>

Object

org.apache.spark.util.random.PoissonSampler<T>

Type Parameters:

T - item type

All Implemented Interfaces:

java.io.Serializable, Cloneable, Pseudorandom, RandomSampler<T,T>

public class PoissonSampler<T>
extends Object
implements RandomSampler<T,T>

A sampler for sampling with replacement, based on values drawn from Poisson distribution.

param: fraction the sampling fraction (with replacement) param: useGapSamplingIfPossible if true, use gap sampling when sampling ratio is low.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
PoissonSampler(double fraction)
PoissonSampler(double fraction, boolean useGapSamplingIfPossible)

Method Summary

Modifier and Type	Method and Description
PoissonSampler<T>	clone() return a copy of the RandomSampler object
int	sample() Whether to sample the next item or not.
scala.collection.Iterator<T>	sample(scala.collection.Iterator<T> items) take a random sample
void	setSeed(long seed) Set random seed.

Methods inherited from class Object

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

Constructor Detail

PoissonSampler

public PoissonSampler(double fraction,
                      boolean useGapSamplingIfPossible)

PoissonSampler

public PoissonSampler(double fraction)

Method Detail

clone

public PoissonSampler<T> clone()

Description copied from interface: RandomSampler

return a copy of the RandomSampler object

Specified by:

clone in interface RandomSampler<T,T>

Overrides:

clone in class Object

sample

public int sample()

Description copied from interface: RandomSampler

Whether to sample the next item or not. Return how many times the next item will be sampled. Return 0 if it is not sampled.

Specified by:

sample in interface RandomSampler<T,T>

Returns:

(undocumented)

sample

public scala.collection.Iterator<T> sample(scala.collection.Iterator<T> items)

Description copied from interface: RandomSampler

take a random sample

Specified by:

sample in interface RandomSampler<T,T>

setSeed

public void setSeed(long seed)

Description copied from interface: Pseudorandom

Set random seed.

Specified by:

setSeed in interface Pseudorandom