jenes.utils

Class Random

java.lang.Object

jenes.utils.MersenneTwisterFast

jenes.utils.Random

All Implemented Interfaces:

java.io.Serializable

public class Random
extends MersenneTwisterFast

This class provides the random generator used by JENES.

Random extends the MersenneTwisterFast class with some methods useful to JENES for obtaining values within a range.

Random implements the singleton design pattern, thus only one instance of Random is available and retrieved by invoking the method getInstance().

The random sequence is controlled by the seed. The standard seed assures that the same sequence of random values is produced by different runs. The time based seed, assures that the sequences varies run by run.

Since:

1.0

Version:

1.2

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static long	STANDARD_SEED The seed used as default

Method Summary

Methods

Modifier and Type	Method and Description
static Random	getInstance() Returns the Random singleton.
static Random	getInstance(long seed) Returns the Random sigleton imposing the seed given as argument
long	getSeed() Return the current seed used for random
boolean	nextBoolean(double coin) Returns a random boolean value.
double	nextDouble(double bound) Returns a random double uniformly distributed within the interval [0,bound[.
double	nextDouble(double lowerBound, double upperBound) Returns a double uniformly distributed within the interval [lowerBound,upperBound[.
int	nextInt(int lowerBound, int upperBound) Returns a random integer drawn uniformly in the interval [lowerBound, upperBound[.
void	setStandardSeed() Sets the stardard value as Random seed.
void	setTimeSeed() Sets the current time as Random seed.

Methods inherited from class jenes.utils.MersenneTwisterFast

main, nextBoolean, nextByte, nextBytes, nextChar, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong, nextShort, setSeed

Methods inherited from class java.lang.Object

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

Field Detail

STANDARD_SEED

public static final long STANDARD_SEED

The seed used as default

See Also:

Constant Field Values

Method Detail

getInstance

public static Random getInstance()

Returns the Random singleton. At the first invocation the Random object is instantiated.

Returns:

the Random instance

getInstance

public static Random getInstance(long seed)

Returns the Random sigleton imposing the seed given as argument

Parameters:

seed -

Returns:

setTimeSeed

public final void setTimeSeed()

Sets the current time as Random seed. This method will make the Random sequence of values different run by run.

setStandardSeed

public final void setStandardSeed()

Sets the stardard value as Random seed. This method will assure the Random sequence of values will not change by run. It should be used for debugging purpose only.

getSeed

public long getSeed()

Return the current seed used for random

Overrides:

getSeed in class MersenneTwisterFast

Returns:

nextDouble

public final double nextDouble(double bound)

Returns a random double uniformly distributed within the interval [0,bound[. Please note that bound is excluded.

Parameters:

bound - the upper bound

Returns:

a random double uniformly distributed within [0,bound[

nextDouble

public final double nextDouble(double lowerBound,
                double upperBound)

Returns a double uniformly distributed within the interval [lowerBound,upperBound[. Please note that the upperBound is excluded.

Parameters:

lowerBound - the interval lower bound

upperBound - the interval upper bound

Returns:

a double uniformly distributed within [lowerBound,upperBound[

nextInt

public final int nextInt(int lowerBound,
          int upperBound)

Returns a random integer drawn uniformly in the interval [lowerBound, upperBound[. Please note that upperBound is excluded. Thus the integer is between lowerBound and upperBound-1.

Parameters:

lowerBound - the interval lower bound

upperBound - the interval upper bound

Returns:

an integer drawn uniformly from lowerBound to upperBound-1.

nextBoolean

public final boolean nextBoolean(double coin)

Returns a random boolean value.

Parameters:

coin - the probability to have a true value

Returns:

a boolean value