Catalano.Math.Random

Class Pcg32

java.lang.Object

Catalano.Math.Random.Pcg32

All Implemented Interfaces:

IRandomNumberGenerator

public class Pcg32
extends java.lang.Object
implements IRandomNumberGenerator

An instance of this class is used to generate a stream of pseudorandom numbers, similarly to Random.

The main differences are:

• PCG algorithm is used; in particular, this is a port of the minimal C implementation.
• Instances of Pcg32 are not thread-safe and so it doesn't obey Random contract.

Constructor Summary

Constructors

Constructor and Description
Pcg32() Creates a new random number generator using current time (returned by System.nanoTime()) as the seed and a unique stream number.
Pcg32(long initState, long initSeq) Creates a new random number generator using a long seed and a long stream number.

Method Summary

Modifier and Type	Method and Description
int	nextBits(int bits) Returns up to 32 random bits.
boolean	nextBoolean() Returns the next pseudorandom, approximately uniformly distributed boolean value.
double	nextDouble() Returns the next pseudorandom, approximately uniformly distributed double value between 0.0 (inclusive) and 1.0 (exclusive).
double	nextDouble(double bound) Returns the next pseudorandom, approximately uniformly distributed double value between 0.0 (inclusive) and bound (exclusive).
void	nextDoubles(double[] d) Returns a vector of pseudorandom, uniformly distributed double values between 0.0 and 1.0 from this random number generator's sequence.
float	nextFloat() Returns the next pseudorandom, approximately uniformly distributed float value between 0.0 (inclusive) and 1.0 (exclusive).
float	nextFloat(float bound) Returns the next pseudorandom, approximately uniformly distributed float value between 0.0 (inclusive) and bound (exclusive).
double	nextGaussian() Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
double	nextGaussian(double mean, double standardDeviation) Returns the next pseudorandom, Gaussian ("normally") distributed double value with given mean and standard deviation from this random number generator's sequence.
int	nextInt() Returns the next pseudorandom, approximately uniformly distributed int value from this random number generator's sequence.
int	nextInt(int n) Returns the next pseudorandom, approximately uniformly distributed int value between 0 (inclusive) and n (exclusive).
long	nextLong() Returns the next pseudorandom, approximately uniformly distributed long value from this random number generator's sequence.
long	nextLong(long n) Returns the next pseudorandom, approximately uniformly distributed long value between 0 (inclusive) and n (exclusive).
void	seed() Initializes the generator with current time as the state and a (very likely to be) unique stream number.
void	seed(long initState, long initSeq)
void	setSeed(long seed) Set seed.

Methods inherited from class java.lang.Object

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

Constructor Detail

Pcg32

public Pcg32(long initState,
             long initSeq)

Creates a new random number generator using a long seed and a long stream number.

The invocation new Pcg32(initState, initSeq) is equivalent to:

 
 Pcg32 rnd = new Pcg32();
 rnd.seed(initState, initSeq);
 

See Also:

seed(long, long)

Pcg32

public Pcg32()

Creates a new random number generator using current time (returned by System.nanoTime()) as the seed and a unique stream number.

See Also:

seed()

Method Detail

setSeed

public void setSeed(long seed)

Description copied from interface: IRandomNumberGenerator

Set seed.

Specified by:

setSeed in interface IRandomNumberGenerator

Parameters:

seed - Seed.

nextInt

public int nextInt()

Returns the next pseudorandom, approximately uniformly distributed int value from this random number generator's sequence. The general contract of nextInt is that one int value is pseudorandomly generated and returned. All 2³² possible int values are produced with (approximately) equal probability.

Specified by:

nextInt in interface IRandomNumberGenerator

See Also:

Random.nextInt()

nextInt

public int nextInt(int n)

Returns the next pseudorandom, approximately uniformly distributed int value between 0 (inclusive) and n (exclusive).

Specified by:

nextInt in interface IRandomNumberGenerator

See Also:

Random.nextInt(int)

nextLong

public long nextLong()

Returns the next pseudorandom, approximately uniformly distributed long value from this random number generator's sequence. The general contract of nextLong is that one long value is pseudorandomly generated and returned. All 2⁶⁴ possible long values are produced with (approximately) equal probability.

Specified by:

nextLong in interface IRandomNumberGenerator

See Also:

Random.nextLong()

nextLong

public long nextLong(long n)

Returns the next pseudorandom, approximately uniformly distributed long value between 0 (inclusive) and n (exclusive).

Returns:

nextBoolean

public boolean nextBoolean()

Returns the next pseudorandom, approximately uniformly distributed boolean value.

See Also:

Random.nextBoolean()

nextFloat

public float nextFloat()

Returns the next pseudorandom, approximately uniformly distributed float value between 0.0 (inclusive) and 1.0 (exclusive).

See Also:

Random.nextFloat()

nextFloat

public float nextFloat(float bound)

Returns the next pseudorandom, approximately uniformly distributed float value between 0.0 (inclusive) and bound (exclusive).

nextDouble

public double nextDouble()

Returns the next pseudorandom, approximately uniformly distributed double value between 0.0 (inclusive) and 1.0 (exclusive).

Specified by:

nextDouble in interface IRandomNumberGenerator

See Also:

Random.nextDouble()

nextDouble

public double nextDouble(double bound)

Returns the next pseudorandom, approximately uniformly distributed double value between 0.0 (inclusive) and bound (exclusive).

nextBits

public int nextBits(int bits)

Description copied from interface: IRandomNumberGenerator

Returns up to 32 random bits.

Specified by:

nextBits in interface IRandomNumberGenerator

nextGaussian

public double nextGaussian()

Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.

See Also:

Random.nextGaussian()

nextGaussian

public double nextGaussian(double mean,
                           double standardDeviation)

Returns the next pseudorandom, Gaussian ("normally") distributed double value with given mean and standard deviation from this random number generator's sequence.

seed

public void seed(long initState,
                 long initSeq)

seed

public void seed()

Initializes the generator with current time as the state and a (very likely to be) unique stream number. This ensures that even if multiple generators are initialized using this method while System.nanoTime() returns the same time, they will have different sequences.

nextDoubles

public void nextDoubles(double[] d)

Description copied from interface: IRandomNumberGenerator

Returns a vector of pseudorandom, uniformly distributed double values between 0.0 and 1.0 from this random number generator's sequence.

Specified by:

nextDoubles in interface IRandomNumberGenerator