SSJ  3.3.1
Stochastic Simulation in Java
Public Member Functions | Static Public Member Functions | List of all members
ParetoDist Class Reference

Extends the class ContinuousDistribution for a distribution from the Pareto family, with shape parameter \(\alpha> 0\) and location parameter \(\beta> 0\) [99]  (page 574). More...

Inheritance diagram for ParetoDist:
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Collaboration diagram for ParetoDist:
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Public Member Functions

 ParetoDist (double alpha)
 Constructs a ParetoDist object with parameters \(\alpha=\) alpha and \(\beta= 1\).
 
 ParetoDist (double alpha, double beta)
 Constructs a ParetoDist object with parameters \(\alpha=\) alpha and \(\beta= \) beta.
 
double density (double x)
 
double cdf (double x)
 Returns the distribution function \(F(x)\). More...
 
double barF (double x)
 Returns \(\bar{F}(x) = 1 - F(x)\). More...
 
double inverseF (double u)
 Returns the inverse distribution function \(F^{-1}(u)\), defined in ( inverseF ). More...
 
double getMean ()
 Returns the mean of the distribution function.
 
double getVariance ()
 Returns the variance of the distribution function.
 
double getStandardDeviation ()
 Returns the standard deviation of the distribution function.
 
double getAlpha ()
 Returns the parameter \(\alpha\).
 
double getBeta ()
 Returns the parameter \(\beta\).
 
void setParams (double alpha, double beta)
 Sets the parameter \(\alpha\) and \(\beta\) for this object.
 
double [] getParams ()
 Return a table containing the parameters of the current distribution. More...
 
String toString ()
 Returns a String containing information about the current distribution.
 
- Public Member Functions inherited from ContinuousDistribution
abstract double density (double x)
 Returns \(f(x)\), the density evaluated at \(x\). More...
 
double barF (double x)
 Returns the complementary distribution function. More...
 
double inverseBrent (double a, double b, double u, double tol)
 Computes the inverse distribution function \(x = F^{-1}(u)\), using the Brent-Dekker method. More...
 
double inverseBisection (double u)
 Computes and returns the inverse distribution function \(x = F^{-1}(u)\), using bisection. More...
 
double inverseF (double u)
 Returns the inverse distribution function \(x = F^{-1}(u)\). More...
 
double getMean ()
 Returns the mean. More...
 
double getVariance ()
 Returns the variance. More...
 
double getStandardDeviation ()
 Returns the standard deviation. More...
 
double getXinf ()
 Returns \(x_a\) such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 
double getXsup ()
 Returns \(x_b\) such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 
void setXinf (double xa)
 Sets the value \(x_a=\) xa, such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 
void setXsup (double xb)
 Sets the value \(x_b=\) xb, such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 

Static Public Member Functions

static double density (double alpha, double beta, double x)
 Computes the density function.
 
static double cdf (double alpha, double beta, double x)
 Computes the distribution function.
 
static double barF (double alpha, double beta, double x)
 Computes the complementary distribution function.
 
static double inverseF (double alpha, double beta, double u)
 Computes the inverse of the distribution function.
 
static double [] getMLE (double[] x, int n)
 Estimates the parameters \((\alpha,\beta)\) of the Pareto distribution using the maximum likelihood method, from the \(n\) observations \(x[i]\), \(i = 0, 1,…, n-1\). More...
 
static ParetoDist getInstanceFromMLE (double[] x, int n)
 Creates a new instance of a Pareto distribution with parameters \(\alpha\) and \(\beta\) estimated using the maximum likelihood method based on the \(n\) observations \(x[i]\), \(i = 0, 1, …, n-1\). More...
 
static double getMean (double alpha, double beta)
 Computes and returns the mean \(E[X] = \alpha\beta/(\alpha- 1)\) of the Pareto distribution with parameters \(\alpha\) and \(\beta\). More...
 
static double getVariance (double alpha, double beta)
 Computes and returns the variance \(\mbox{Var}[X] = \frac{\alpha\beta^2}{(\alpha- 2)(\alpha- 1)}\) of the Pareto distribution with parameters \(\alpha\) and \(\beta\). More...
 
static double getStandardDeviation (double alpha, double beta)
 Computes and returns the standard deviation of the Pareto distribution with parameters \(\alpha\) and \(\beta\). More...
 

Additional Inherited Members

- Public Attributes inherited from ContinuousDistribution
int decPrec = 15
 
- Protected Attributes inherited from ContinuousDistribution
double supportA = Double.NEGATIVE_INFINITY
 
double supportB = Double.POSITIVE_INFINITY
 
- Static Protected Attributes inherited from ContinuousDistribution
static final double XBIG = 100.0
 
static final double XBIGM = 1000.0
 
static final double [] EPSARRAY
 

Detailed Description

Extends the class ContinuousDistribution for a distribution from the Pareto family, with shape parameter \(\alpha> 0\) and location parameter \(\beta> 0\) [99]  (page 574).

The density for this type of Pareto distribution is

\[ f(x) = \frac{\alpha\beta^{\alpha}}{x^{\alpha+1}} \qquad\mbox{for }x \ge\beta, \tag{fpareto} \]

and 0 otherwise. The distribution function is

\[ F(x) = 1 - \left(\beta/x\right)^{\alpha}\qquad\mbox{for }x\ge\beta, \tag{Fpareto} \]

and the inverse distribution function is

\[ F^{-1}(u) = \beta(1 - u)^{-1/\alpha} \qquad\mbox{for } 0 \le u < 1. \]

Member Function Documentation

◆ barF()

double barF ( double  x)

Returns \(\bar{F}(x) = 1 - F(x)\).

Parameters
xvalue at which the complementary distribution function is evaluated
Returns
complementary distribution function evaluated at x

Implements Distribution.

◆ cdf()

double cdf ( double  x)

Returns the distribution function \(F(x)\).

Parameters
xvalue at which the distribution function is evaluated
Returns
distribution function evaluated at x

Implements Distribution.

◆ getInstanceFromMLE()

static ParetoDist getInstanceFromMLE ( double []  x,
int  n 
)
static

Creates a new instance of a Pareto distribution with parameters \(\alpha\) and \(\beta\) estimated using the maximum likelihood method based on the \(n\) observations \(x[i]\), \(i = 0, 1, …, n-1\).

Parameters
xthe list of observations to use to evaluate parameters
nthe number of observations to use to evaluate parameters

◆ getMean()

static double getMean ( double  alpha,
double  beta 
)
static

Computes and returns the mean \(E[X] = \alpha\beta/(\alpha- 1)\) of the Pareto distribution with parameters \(\alpha\) and \(\beta\).

Returns
the mean of the Pareto distribution

◆ getMLE()

static double [] getMLE ( double []  x,
int  n 
)
static

Estimates the parameters \((\alpha,\beta)\) of the Pareto distribution using the maximum likelihood method, from the \(n\) observations \(x[i]\), \(i = 0, 1,…, n-1\).

The estimates are returned in a two-element array, in regular order: [ \(\alpha\), \(\beta\)]. The maximum likelihood estimators are the values \((\hat{\alpha}, \hat{\beta})\) that satisfy the equations:

\begin{align*} \hat{\beta} & = \min_i \{x_i\} \\ \hat{\alpha} & = \frac{n}{\sum_{i=1}^n \ln\left(\frac{x_i}{\hat{\beta}\Rule{0.0pt}{5.5pt}{0.0pt}}\right)}. \end{align*}

See [99]  (page 581).

Parameters
xthe list of observations used to evaluate parameters
nthe number of observations used to evaluate parameters
Returns
returns the parameters [ \(\hat{\alpha}\), \(\hat{\beta}\)]

◆ getParams()

double [] getParams ( )

Return a table containing the parameters of the current distribution.

This table is put in regular order: [ \(\alpha\), \(\beta\)].

Implements Distribution.

◆ getStandardDeviation()

static double getStandardDeviation ( double  alpha,
double  beta 
)
static

Computes and returns the standard deviation of the Pareto distribution with parameters \(\alpha\) and \(\beta\).

Returns
the standard deviation of the Pareto distribution

◆ getVariance()

static double getVariance ( double  alpha,
double  beta 
)
static

Computes and returns the variance \(\mbox{Var}[X] = \frac{\alpha\beta^2}{(\alpha- 2)(\alpha- 1)}\) of the Pareto distribution with parameters \(\alpha\) and \(\beta\).

Returns
the variance of the Pareto distribution \(\mbox{Var}[X] = \alpha\beta^2 / [(\alpha- 2)(\alpha- 1)]\)

◆ inverseF()

double inverseF ( double  u)

Returns the inverse distribution function \(F^{-1}(u)\), defined in ( inverseF ).

Parameters
uvalue in the interval \((0,1)\) for which the inverse distribution function is evaluated
Returns
the inverse distribution function evaluated at u

Implements Distribution.


The documentation for this class was generated from the following file: