de.lmu.ifi.dbs.elki.data

Class VectorUtil

java.lang.Object

de.lmu.ifi.dbs.elki.data.VectorUtil

public final class VectorUtil
extends Object

Utility functions for use with vectors. Note: obviously, many functions are class methods or database related.

Constructor Summary

Constructors

Constructor and Description
VectorUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static double	angle(NumberVector<?,?> v1, NumberVector<?,?> v2, NumberVector<?,?> o) Compute the angle between two vectors.
static double	angle(NumberVector<?,?> v1, NumberVector<?,?> v2, Vector o) Compute the angle between two vectors.
static double	angleSparse(SparseNumberVector<?,?> v1, SparseNumberVector<?,?> v2) Compute the angle for sparse vectors.
static double	cosAngle(NumberVector<?,?> v1, NumberVector<?,?> v2) Compute the absolute cosine of the angle between two vectors.
static DoubleMinMax	getRangeDouble(NumberVector<?,?> vec) Return the range across all dimensions.
static double	minCosAngle(SpatialComparable v1, SpatialComparable v2) Compute the minimum angle between two rectangles.
static <V extends NumberVector<V,?>> V	randomVector(V template) Produce a new vector based on random numbers in [0:1] of the same type and dimensionality as the given vector.
static <V extends NumberVector<V,?>> V	randomVector(V template, Random r) Produce a new vector based on random numbers in [0:1] of the same type and dimensionality as the given vector.
static double	scalarProduct(NumberVector<?,?> d1, NumberVector<?,?> d2) Provides the scalar product (inner product) of this and the given DoubleVector.

Methods inherited from class java.lang.Object

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

Constructor Detail

VectorUtil

public VectorUtil()

Method Detail

getRangeDouble

public static DoubleMinMax getRangeDouble(NumberVector<?,?> vec)

Return the range across all dimensions. Useful in particular for time series.

Parameters:

vec - Vector to process.

Returns:

[min, max]

randomVector

public static <V extends NumberVector<V,?>> V randomVector(V template,
                                           Random r)

Produce a new vector based on random numbers in [0:1] of the same type and dimensionality as the given vector.

Parameters:

template - existing instance of wanted dimensionality.

r - Random generator

Returns:

new instance

randomVector

public static <V extends NumberVector<V,?>> V randomVector(V template)

Produce a new vector based on random numbers in [0:1] of the same type and dimensionality as the given vector.

Parameters:

template - existing instance of wanted dimensionality.

Returns:

new instance

angleSparse

public static double angleSparse(SparseNumberVector<?,?> v1,
                 SparseNumberVector<?,?> v2)

Compute the angle for sparse vectors.

Parameters:

v1 - First vector

v2 - Second vector

Returns:

angle

angle

public static double angle(NumberVector<?,?> v1,
           NumberVector<?,?> v2,
           Vector o)

Compute the angle between two vectors.

Parameters:

v1 - first vector

v2 - second vector

o - Origin

Returns:

Angle

angle

public static double angle(NumberVector<?,?> v1,
           NumberVector<?,?> v2,
           NumberVector<?,?> o)

Compute the angle between two vectors.

Parameters:

v1 - first vector

v2 - second vector

o - Origin

Returns:

Angle

cosAngle

public static double cosAngle(NumberVector<?,?> v1,
              NumberVector<?,?> v2)

Compute the absolute cosine of the angle between two vectors. To convert it to radians, use Math.acos(angle)!

Parameters:

v1 - first vector

v2 - second vector

Returns:

Angle

minCosAngle

public static double minCosAngle(SpatialComparable v1,
                 SpatialComparable v2)

Compute the minimum angle between two rectangles.

Parameters:

v1 - first rectangle

v2 - second rectangle

Returns:

Angle

scalarProduct

public static double scalarProduct(NumberVector<?,?> d1,
                   NumberVector<?,?> d2)

Provides the scalar product (inner product) of this and the given DoubleVector.

Parameters:

d1 - the first vector to compute the scalar product for

d2 - the second vector to compute the scalar product for

Returns:

the scalar product (inner product) of this and the given DoubleVector