org.apache.commons.math.random
Class ValueServer

java.lang.Object
  org.apache.commons.math.random.ValueServer

public class ValueServer

extends Object

Generates values for use in simulation applications.

How values are generated is determined by the mode property.

Supported mode values are:

• DIGEST_MODE -- uses an empirical distribution
• REPLAY_MODE -- replays data from valuesFileURL
• UNIFORM_MODE -- generates uniformly distributed random values with mean = mu
• EXPONENTIAL_MODE -- generates exponentially distributed random values with mean = mu
• GAUSSIAN_MODE -- generates Gaussian distributed random values with mean = mu and standard deviation = sigma
• CONSTANT_MODE -- returns mu every time.

Version:

$Revision: 1.17 $ $Date: 2004/08/22 01:41:30 $

Field Summary

static int	CONSTANT_MODE Always return mu
static int	DIGEST_MODE Use empirical distribution
static int	EXPONENTIAL_MODE Exponential random deviates with mean = mu
static int	GAUSSIAN_MODE Gaussian random deviates with mean = mu, std dev = sigma
static int	REPLAY_MODE Replay data from valuesFilePath
static int	UNIFORM_MODE Uniform random deviates with mean = mu

Constructor Summary

ValueServer()
Creates new ValueServer

Method Summary

void	closeReplayFile() Closes valuesFileURL after use in REPLAY_MODE.
void	computeDistribution() Computes the empirical distribution using values from the file in valuesFileURL, using the default number of bins.
void	computeDistribution(int binCount) Computes the empirical distribution using values from the file in valuesFileURL and binCount bins.
void	fill(double[] values) Fills the input array with values generated using getNext() repeatedly.
double[]	fill(int length) Returns an array of length length with values generated using getNext() repeatedly.
EmpiricalDistribution	getEmpiricalDistribution() Getter for property empiricalDistribution.
int	getMode() Getter for property mode.
double	getMu() Getter for property mu.
double	getNext() Returns the next generated value, generated according to the mode value (see MODE constants).
double	getSigma() Getter for property sigma.
URL	getValuesFileURL() Getter for valuesFileURL
void	resetReplayFile() Resets REPLAY_MODE file pointer to the beginning of the valuesFileURL.
void	setMode(int mode) Setter for property mode.
void	setMu(double mu) Setter for property mu.
void	setSigma(double sigma) Setter for property sigma.
void	setValuesFileURL(String url) Sets the valuesFileURL using a string URL representation
void	setValuesFileURL(URL url) Sets the valuesFileURL

Methods inherited from class java.lang.Object

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

Field Detail

DIGEST_MODE

public static final int DIGEST_MODE

Use empirical distribution

See Also:

Constant Field Values

REPLAY_MODE

public static final int REPLAY_MODE

Replay data from valuesFilePath

See Also:

Constant Field Values

UNIFORM_MODE

public static final int UNIFORM_MODE

Uniform random deviates with mean = mu

See Also:

Constant Field Values

EXPONENTIAL_MODE

public static final int EXPONENTIAL_MODE

Exponential random deviates with mean = mu

See Also:

Constant Field Values

GAUSSIAN_MODE

public static final int GAUSSIAN_MODE

Gaussian random deviates with mean = mu, std dev = sigma

See Also:

Constant Field Values

CONSTANT_MODE

public static final int CONSTANT_MODE

Always return mu

See Also:

Constant Field Values

Constructor Detail

ValueServer

public ValueServer()

Creates new ValueServer

Method Detail

getNext

public double getNext()
               throws IOException

Returns the next generated value, generated according to the mode value (see MODE constants).

Returns:

generated value

Throws:

IOException - in REPLAY_MODE if a file I/O error occurs

fill

public void fill(double[] values)
          throws IOException

Fills the input array with values generated using getNext() repeatedly.

Parameters:

values - array to be filled

Throws:

IOException - in REPLAY_MODE if a file I/O error occurs

fill

public double[] fill(int length)
              throws IOException

Returns an array of length length with values generated using getNext() repeatedly.

Parameters:

length - length of output array

Returns:

array of generated values

Throws:

IOException - in REPLAY_MODE if a file I/O error occurs

computeDistribution

public void computeDistribution()
                         throws IOException

Computes the empirical distribution using values from the file in valuesFileURL, using the default number of bins.

valuesFileURL must exist and be readable by *this at runtime.

This method must be called before using getNext() with mode = DISGEST_MODE

Throws:

IOException - if an I/O error occurs reading the input file

computeDistribution

public void computeDistribution(int binCount)
                         throws IOException

Computes the empirical distribution using values from the file in valuesFileURL and binCount bins.

valuesFileURL must exist and be readable by *this at runtime.

This method must be called before using getNext() with mode = DISGEST_MODE

Parameters:

binCount - the number of bins used in computing the empirical distribution

Throws:

IOException - if an error occurs reading the input file

getMode

public int getMode()

Getter for property mode.

Returns:

Value of property mode.

setMode

public void setMode(int mode)

Setter for property mode.

Parameters:

mode - New value of property mode.

getValuesFileURL

public URL getValuesFileURL()

Getter for valuesFileURL

Returns:

Value of property valuesFileURL.

setValuesFileURL

public void setValuesFileURL(String url)
                      throws MalformedURLException

Sets the valuesFileURL using a string URL representation

Parameters:

url - String representation for new valuesFileURL.

Throws:

MalformedURLException - if url is not well formed

setValuesFileURL

public void setValuesFileURL(URL url)

Sets the valuesFileURL

Parameters:

url - New value of property valuesFileURL.

getEmpiricalDistribution

public EmpiricalDistribution getEmpiricalDistribution()

Getter for property empiricalDistribution.

Returns:

Value of property empiricalDistribution.

resetReplayFile

public void resetReplayFile()
                     throws IOException

Resets REPLAY_MODE file pointer to the beginning of the valuesFileURL.

Throws:

IOException - if an error occurs opening the file

closeReplayFile

public void closeReplayFile()
                     throws IOException

Closes valuesFileURL after use in REPLAY_MODE.

Throws:

IOException - if an error occurs closing the file

getMu

public double getMu()

Getter for property mu.

Returns:

Value of property mu.

setMu

public void setMu(double mu)

Setter for property mu.

Parameters:

mu - New value of property mu.

getSigma

public double getSigma()

Getter for property sigma.

Returns:

Value of property sigma.

setSigma

public void setSigma(double sigma)

Setter for property sigma.

Parameters:

sigma - New value of property sigma.