org.apache.tinkerpop.gremlin.algorithm.generator

Class PowerLawDistribution

java.lang.Object

org.apache.tinkerpop.gremlin.algorithm.generator.PowerLawDistribution

All Implemented Interfaces:

Distribution

public class PowerLawDistribution
extends Object
implements Distribution

Generates values according to a scale-free distribution with the configured gamma value.

Author:

Matthias Broecheler (me@matthiasb.com)

Constructor Summary

Constructors

Constructor and Description
PowerLawDistribution(double gamma) Constructs a new scale-free distribution for the provided gamma value.

Method Summary

Modifier and Type	Method and Description
static int	getValue(Random random, double multiplier, double beta)
Distribution	initialize(int invocations, int expectedTotal) Initializes the distribution such that expectedTotal is equal to the expected sum of generated values after the given number of invocatiosn.
int	nextConditionalValue(Random random, int otherValue) Returns the next value conditional on another given value.
int	nextValue(Random random) Returns the next value.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

PowerLawDistribution

public PowerLawDistribution(double gamma)

Constructs a new scale-free distribution for the provided gamma value.

Method Detail

initialize

public Distribution initialize(int invocations,
                               int expectedTotal)

Description copied from interface: Distribution

Initializes the distribution such that expectedTotal is equal to the expected sum of generated values after the given number of invocatiosn.

Since most distributions have an element of randomness, these values are the expected values.

Specified by:

initialize in interface Distribution

Returns:

A new distribution configured to match the expected total for the number of invocations.

nextValue

public int nextValue(Random random)

Description copied from interface: Distribution

Returns the next value. If this value is randomly generated, the randomness must be drawn from the provided random generator.

DO NOT use your own internal random generator as this makes the generated values non-reproducible and leads to faulty behavior.

Specified by:

nextValue in interface Distribution

Parameters:

random - random generator to use for randomness

Returns:

next value

nextConditionalValue

public int nextConditionalValue(Random random,
                                int otherValue)

Description copied from interface: Distribution

Returns the next value conditional on another given value.

This can be used, for instance, to define conditional degree distributions where the in-degree is conditional on the out-degree.

If this value is randomly generated, the randomness must be drawn from the provided random generator. DO NOT use your own internal random generator as this makes the generated values non-reproducible and leads to faulty behavior.

Specified by:

nextConditionalValue in interface Distribution

Parameters:

random - random generator to use for randomness

otherValue - The prior value

Returns:

next value

toString

public String toString()

Overrides:

toString in class Object

getValue

public static int getValue(Random random,
                           double multiplier,
                           double beta)