tbgitoo.tools

Class VectorTools

java.lang.Object

tbgitoo.tools.VectorTools

public class VectorTools
extends java.lang.Object

Some standard functions applied to vectors

Author:

thomasbraschler

Constructor Summary

Constructors

Constructor and Description
VectorTools()

Method Summary

Modifier and Type	Method and Description
static double[]	element_wise_multiplication(double[] x, double[] y) Element-wise multiplication of two vectors.
static boolean	findInVector(int needle, java.util.Vector<java.lang.Integer> haystack) Is a given value in a vector?
static int[]	getIndexesOfValuesExceedingThreshold(double[] vals, double threshold) /Indexes of the values at or above the threshold
static double	mean(double[] x) Mean of the values in a vector
static double	scalar_product(double[] x, double[] y) Scalar product of two vectors.
static java.util.Vector<java.lang.Integer>	setDiff(java.util.Vector<java.lang.Integer> a, java.util.Vector<java.lang.Integer> b) Ensemble difference: Returns all the elements that are in a but could not be found in b
static double	sum(double[] x) Sum of the values in a vector
static int	sum(int[] x) Sum of the values in a vector
static double	vector_norm(double[] x) Pythagorean length of the vector: sqrt(x1^2+x2^2+..)

Methods inherited from class java.lang.Object

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

Constructor Detail

VectorTools

public VectorTools()

Method Detail

mean

public static double mean(double[] x)

Mean of the values in a vector

Parameters:

x - The vector of values

Returns:

The arithmetic mean of the values in the vector. 0 if vector length 0 is provided

vector_norm

public static double vector_norm(double[] x)

Pythagorean length of the vector: sqrt(x1^2+x2^2+..)

Parameters:

x - The vector of values

Returns:

The Pythogerean (Euclidian) norm of the vector

scalar_product

public static double scalar_product(double[] x,
                                    double[] y)

Scalar product of two vectors. If not of the same length, the shorter is length is considered only

Parameters:

x - First vector of values

y - Second vector of values

Returns:

Scalar product

element_wise_multiplication

public static double[] element_wise_multiplication(double[] x,
                                                   double[] y)

Element-wise multiplication of two vectors. If not of the same length, multiplication is only carried out up to the end of the shorter vector

Parameters:

x - First vector of values

y - Second vector of values

Returns:

Vector of the same length as x and y (or the shorter of the two if different)

sum

public static int sum(int[] x)

Sum of the values in a vector

Parameters:

x - The vector of values

Returns:

The sum of values in the vector. 0 if vector length 0 is provided

sum

public static double sum(double[] x)

Sum of the values in a vector

Parameters:

x - The vector of values

Returns:

The sum of values in the vector. 0 if vector length 0 is provided

findInVector

public static boolean findInVector(int needle,
                                   java.util.Vector<java.lang.Integer> haystack)

Is a given value in a vector?

Parameters:

needle - The value to be searched

haystack - The vector to be searched through

Returns:

True if needle was found in haystack, false otherwise

setDiff

public static java.util.Vector<java.lang.Integer> setDiff(java.util.Vector<java.lang.Integer> a,
                                                          java.util.Vector<java.lang.Integer> b)

Ensemble difference: Returns all the elements that are in a but could not be found in b

Parameters:

a - Vector with candidate elements to be tested

b - Vector with disallowed elements that should not be in output

Returns:

Vector of all values in a that could not be found in b

getIndexesOfValuesExceedingThreshold

public static int[] getIndexesOfValuesExceedingThreshold(double[] vals,
                                                         double threshold)

/Indexes of the values at or above the threshold

Parameters:

vals - Array of values

threshold - Minimal threshold required for elements to be eligible

Returns:

Array of indexes to the elements with values above the threshold