Module org.cicirello.rho_mu

Package org.cicirello.math

Class MathFunctions

java.lang.Object

org.cicirello.math.MathFunctions

public final class MathFunctions
extends Object

MathFunctions is a class of utility methods that implement various mathematical functions.

Method Summary

Modifier and Type	Method	Description
static double	betai(double a, double b, double x)	Computes the incomplete beta function: IX(a, b).
static double	logGamma(double n)	Implementation of the natural log of the absolute value of the gamma function.
static double	pow(double a, int b)	Computes ab, where the exponent b is an integer.

Methods inherited from class java.lang.Object

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

Method Details

betai

public static double betai(double a,
 double b,
 double x)

Computes the incomplete beta function: I_X(a, b).

Parameters:

a - the parameter, a, of the incomplete beta function

b - the parameter, b, of the incomplete beta function

x - the parameter, x, of the incomplete beta function

Returns:

I_X(a, b)

Throws:

IllegalArgumentException - if x is negative or greater than 1

ArithmeticException - if the continued fraction evaluation fails to converge, such as if either a or b are too large, or if the continued fraction evaluation is using too few iterations

pow

public static double pow(double a,
 int b)

Computes a^b, where the exponent b is an integer. This is more efficient than using Math.pow(double, double) since it exploits the integer type of the exponent.

Parameters:

a - The base.

b - The exponent.

Returns:

a^b

logGamma

public static double logGamma(double n)

Implementation of the natural log of the absolute value of the gamma function.

Parameters:

n - input parameter to the function

Returns:

ln(abs(gamma(n)))