Package com.tagtraum.audiokern.math

Class Integers

java.lang.Object

com.tagtraum.audiokern.math.Integers

public final class Integers
extends Object

Utility methods for ints.

Author:

Hendrik Schreiber

Method Summary

Modifier and Type	Method	Description
static void	abs(int[] array)	Changes all values to their absolute values.
static double	arithmeticMean(int[] array)	Computes the arithmetic mean of the array.
static double	arithmeticMean(int[] array, int start, int end)	Computes the arithmetic mean of a portion of an array.
static boolean	isPowerOfTwo(int number)	Indicates whether a number is a power of two.
static int	max(int[] array)	Calculates the min value of a given array.
static float	maximalAccumulatedSimilarity(int[] x, int[] y, DistanceFunction<Integer> similarityFunction)	Computes the dynamic timewarping similarity (i.e.
static int	maxIndex(int[] array)	Calculates the index of the max value of a given array.
static int	maxIndex(int[] array, int offset, int length)	Calculates the index of the max value of a given array.
static int[]	maxIndices(int[] array)	Calculates the indices of the max values of a given array in descending value order.
static int[]	maxIndices(int[] array, int offset, int length)	Calculates the indices of the max values of a given array in descending value order.
static int	min(int[] array)	Calculates the min value of a given array.
static float	minimalAccumulatedDistance(int[] x, int[] y, DistanceFunction<Integer> distanceFunction)	Computes the dynamic timewarping distance (i.e.
static void	normalize(int[][] arrayOfArrays, int scale)	Normalizes the values in the given arrays to values 0..scale.
static void	normalize(int[] array, int scale)	Normalizes the values in the given array to values 0..scale.
static int[]	peaks(int[] array, int interval, boolean strict)	Calculates all peaks in the given array.
static void	reverse(int[] array)	Reverses the order of the ints in place.
static float	standardDeviation(int[] data)
static float	standardDeviation(int[] data, int offset, int length)
static float	variance(int[] array)
static float	variance(int[] array, int offset, int length)

Methods inherited from class java.lang.Object

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

Method Detail

reverse

public static void reverse(int[] array)

Reverses the order of the ints in place.

Parameters:

array - int array

arithmeticMean

public static double arithmeticMean(int[] array,
                                    int start,
                                    int end)

Computes the arithmetic mean of a portion of an array.

Parameters:

array - array

start - first index (incl)

end - last index (excl)

Returns:

mean

arithmeticMean

public static double arithmeticMean(int[] array)

Computes the arithmetic mean of the array.

Parameters:

array - array

Returns:

mean

variance

public static float variance(int[] array)

variance

public static float variance(int[] array,
                             int offset,
                             int length)

standardDeviation

public static float standardDeviation(int[] data)

standardDeviation

public static float standardDeviation(int[] data,
                                      int offset,
                                      int length)

abs

public static void abs(int[] array)

Changes all values to their absolute values.

Parameters:

array - integer array

min

public static int min(int[] array)

Calculates the min value of a given array.

Parameters:

array - integer array

Returns:

minimum

max

public static int max(int[] array)

Calculates the min value of a given array.

Parameters:

array - integer array

Returns:

max

maxIndex

public static int maxIndex(int[] array,
                           int offset,
                           int length)

Calculates the index of the max value of a given array.

Parameters:

array - int array

offset - offset into the array

length - length

Returns:

max

maxIndices

public static int[] maxIndices(int[] array)

Calculates the indices of the max values of a given array in descending value order.

Parameters:

array - int array

Returns:

max indices

maxIndices

public static int[] maxIndices(int[] array,
                               int offset,
                               int length)

Calculates the indices of the max values of a given array in descending value order.

Parameters:

array - int array

offset - offset into the array

length - length

Returns:

max indices

peaks

public static int[] peaks(int[] array,
                          int interval,
                          boolean strict)

Calculates all peaks in the given array. A peak is defined as a value with at least interval values to its left that are strictly less than their direct neighbors to the right, and at least interval values to its right that are strictly less than their direct neighbors to the left.

Parameters:

array - array

interval - number of values to the left and the right that the function has to be increasing or decreasing

strict - if true, the shoulders of the peak must be strictly monotonically increasing or decreasing

Returns:

indices of the detected peaks

maxIndex

public static int maxIndex(int[] array)

Calculates the index of the max value of a given array.

Parameters:

array - int array

Returns:

max

normalize

public static void normalize(int[] array,
                             int scale)

Normalizes the values in the given array to values 0..scale. Note: This method manipulates the provided array.

Parameters:

array - array of integers

scale - scale

normalize

public static void normalize(int[][] arrayOfArrays,
                             int scale)

Normalizes the values in the given arrays to values 0..scale. Note: This method manipulates the provided array.

Parameters:

arrayOfArrays - array of double arrays

scale - scale

isPowerOfTwo

public static boolean isPowerOfTwo(int number)

Indicates whether a number is a power of two.

Parameters:

number - number

Returns:

true, if this number is a power of two (e.g. 4, 8, 16, ...)

minimalAccumulatedDistance

public static float minimalAccumulatedDistance(int[] x,
                                               int[] y,
                                               DistanceFunction<Integer> distanceFunction)

Computes the dynamic timewarping distance (i.e. accumulated cost) between two integer sequences using a given cost function.

Parameters:

x - sequence

y - sequence

distanceFunction - used to compute the local distance between two elements of each sequence

Returns:

total cost of the optimal (i.e. minimal w.r.t cost) warping path between x and y

maximalAccumulatedSimilarity

public static float maximalAccumulatedSimilarity(int[] x,
                                                 int[] y,
                                                 DistanceFunction<Integer> similarityFunction)

Computes the dynamic timewarping similarity (i.e. accumulated similarity) between two integer sequences using a given similarity function.

Parameters:

x - sequence

y - sequence

similarityFunction - used to compute the local distance between two elements of each sequence

Returns:

total similarity of the optimal (i.e. maximal w.r.t. similarity) warping path between x and y