Package es.upm.etsisi.cf4j.util

Class Maths

java.lang.Object

es.upm.etsisi.cf4j.util.Maths

public class Maths
extends Object

This class contains useful math methods.

Constructor Summary

Constructors

Constructor	Description
Maths()

Method Summary

Modifier and Type	Method	Description
static double	arrayAverage(double[] array)	Calculates the average of an double array
static double	arrayAverage(int[] array)	Calculates the average of an int array
static double	arrayStandardDeviation(double[] array)	Calculates the standard deviation of an double array
static double	arrayStandardDeviation(int[] array)	Calculate the standard deviation of an int array
static double	dotProduct(double[] a, double[] b)	Dot product between two vectors
static double	log(double x, double b)	Returns the log in an specific base
static double	logistic(double x)	Returns the logistic function g(x)

Methods inherited from class java.lang.Object

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

Constructor Detail

Maths

public Maths()

Method Detail

arrayAverage

public static double arrayAverage(double[] array)

Calculates the average of an double array

Parameters:

array - Array of double from which to calculate the mean

Returns:

Array mean

arrayStandardDeviation

public static double arrayStandardDeviation(double[] array)

Calculates the standard deviation of an double array

Parameters:

array - Array of double from which to calculate the standard deviation

Returns:

Standard deviation of the array

arrayAverage

public static double arrayAverage(int[] array)

Calculates the average of an int array

Parameters:

array - Array of int from which to calculate the mean

Returns:

Array mean

arrayStandardDeviation

public static double arrayStandardDeviation(int[] array)

Calculate the standard deviation of an int array

Parameters:

array - Array of int from which to calculate the standard deviation

Returns:

Standard deviation of the array

dotProduct

public static double dotProduct(double[] a,
                                double[] b)

Dot product between two vectors

Parameters:

a - Vector A

b - Vector B

Returns:

dot_product(A, B)

log

public static double log(double x,
                         double b)

Returns the log in an specific base

Parameters:

x - Value

b - Base

Returns:

log of x in base b

logistic

public static double logistic(double x)

Returns the logistic function g(x)

Parameters:

x - The given parameter x of the function g(x)

Returns:

Value of the logistic function g(x)