ai.libs.jaicore.ml.tsc.util

Class MathUtil

java.lang.Object

ai.libs.jaicore.ml.tsc.util.MathUtil

public class MathUtil
extends java.lang.Object

Utility class consisting of mathematical utility functions.

Method Summary

Modifier and Type	Method and Description
static int	argmax(int[] array) Calculates the index of the maximum value in the given array (argmax).
static double	intManhattanDistance(int[] a, int[] b) Simple Manhattan distance (sum of the absolute differences between the vectors' elements) implementation for arrays of Integer.
static double	mean(double[] vector, int t1, int t2) Function calculating the mean of the interval [t1, t2 (inclusive)] of the given vector.
static double	sigmoid(double z) Function to calculate the sigmoid for the given value z.
static double	singleSquaredEuclideanDistance(double[] vector1, double[] vector2) Computes the single squared Euclidean distance between two vectors.
static double	slope(double[] vector, int t1, int t2) Function calculating the slope of the interval [t1, t2 (inclusive)] of the given vector.
static double	stddev(double[] vector, int t1, int t2, boolean useBiasCorrection) Function calculating the standard deviation of the interval [t1, t2 (inclusive)] of the given vector.
static double	sum(double[] array) Sums the values of the given array.

Methods inherited from class java.lang.Object

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

Method Detail

sigmoid

public static double sigmoid(double z)

Function to calculate the sigmoid for the given value z.

Parameters:

z - Parameter z

Returns:

Returns the sigmoid for the parameter z.

sum

public static double sum(double[] array)

Sums the values of the given array.

Parameters:

array - The array to be summed

Returns:

Returns the sum of the values

singleSquaredEuclideanDistance

public static double singleSquaredEuclideanDistance(double[] vector1,
                                                    double[] vector2)

Computes the single squared Euclidean distance between two vectors.

Parameters:

vector1 - First argument vector

vector2 - Second argument vector

Returns:

Returns the single squared Euclidean distance between two vectors

intManhattanDistance

public static double intManhattanDistance(int[] a,
                                          int[] b)

Simple Manhattan distance (sum of the absolute differences between the vectors' elements) implementation for arrays of Integer.

Parameters:

a - First argument vector

b - Second argument vector

Returns:

Returns the Manhattan distance of the two given vectors

mean

public static double mean(double[] vector,
                          int t1,
                          int t2)

Function calculating the mean of the interval [t1, t2 (inclusive)] of the given vector.

Parameters:

vector - Vector which is used for the calculation

t1 - Interval start

t2 - Interval end (inclusive)

Returns:

Returns the mean of the vector's interval [t1, t2 (inclusive)]

stddev

public static double stddev(double[] vector,
                            int t1,
                            int t2,
                            boolean useBiasCorrection)

Function calculating the standard deviation of the interval [t1, t2 (inclusive)] of the given vector.

Parameters:

vector - Vector which is used for the calculation

t1 - Interval start

t2 - Interval end (inclusive)

useBiasCorrection - Indicator whether the bias (Bessel's) correction should be used

Returns:

Returns the standard deviation of the vector's interval [t1, t2 (inclusive)]

slope

public static double slope(double[] vector,
                           int t1,
                           int t2)

Function calculating the slope of the interval [t1, t2 (inclusive)] of the given vector.

Parameters:

vector - Vector which is used for the calculation

t1 - Interval start

t2 - Interval end (inclusive)

Returns:

Returns the slope of the vector's interval [t1, t2 (inclusive)]

argmax

public static int argmax(int[] array)

Calculates the index of the maximum value in the given array (argmax).

Parameters:

array - Array to be checked. Must not be null or empty

Returns:

Returns the index of the maximum value