org.apache.commons.geometry.euclidean.internal

Class Vectors

java.lang.Object

org.apache.commons.geometry.euclidean.internal.Vectors

public final class Vectors
extends Object

This class consists exclusively of static vector utility methods.

Method Summary

Modifier and Type	Method and Description
static double	checkedNorm(double norm) Throws an IllegalArgumentException if the given norm value is not real (ie, not NaN or infinite) or zero.
static double	checkedNorm(Vector<?> vec) Returns the vector's norm value, throwing an IllegalArgumentException if the value is not real (ie, not NaN or infinite) or zero.
static IllegalArgumentException	illegalNorm(double norm) Return an exception indicating an illegal norm value.
static boolean	isRealNonZero(double value) Returns true if the given value is real (ie, not NaN or infinite) and not equal to zero.
static double	linearCombination(double a1, double b1, double a2, double b2) Compute the linear combination \(a_1 b_1 + a_2 b_2 \) with high accuracy.
static double	linearCombination(double a1, double b1, double a2, double b2, double a3, double b3) Compute the linear combination \(a_1 b_1 + a_2 b_2 + a_3 b_3 \) with high accuracy.
static double	norm(double x) Get the L2 norm (commonly known as the Euclidean norm) for the vector with the given components.
static double	norm(double x1, double x2) Get the L2 norm (commonly known as the Euclidean norm) for the vector with the given components.
static double	norm(double x1, double x2, double x3) Get the L2 norm (commonly known as the Euclidean norm) for the vector with the given components.
static double	normSq(double x) Get the square of the L2 norm (also known as the Euclidean norm) for the vector with the given components.
static double	normSq(double x1, double x2) Get the square of the L2 norm (also known as the Euclidean norm) for the vector with the given components.
static double	normSq(double x1, double x2, double x3) Get the square of the L2 norm (also known as the Euclidean norm) for the vector with the given components.

Methods inherited from class java.lang.Object

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

Method Detail

isRealNonZero

public static boolean isRealNonZero(double value)

Returns true if the given value is real (ie, not NaN or infinite) and not equal to zero.

Parameters:

value - the value to test

Returns:

true if value is not NaN, infinite, or zero; otherwise false

checkedNorm

public static double checkedNorm(double norm)

Throws an IllegalArgumentException if the given norm value is not real (ie, not NaN or infinite) or zero. The argument is returned to allow this method to be called inline.

Parameters:

norm - vector norm value

Returns:

the validated norm value

Throws:

IllegalArgumentException - if the given norm value is NaN, infinite, or zero

checkedNorm

public static double checkedNorm(Vector<?> vec)

Returns the vector's norm value, throwing an IllegalArgumentException if the value is not real (ie, not NaN or infinite) or zero.

Parameters:

vec - vector to obtain the real, non-zero norm of

Returns:

the validated norm value

Throws:

IllegalArgumentException - if the vector norm value is NaN, infinite, or zero

illegalNorm

public static IllegalArgumentException illegalNorm(double norm)

Return an exception indicating an illegal norm value.

Parameters:

norm - illegal norm value

Returns:

exception indicating an illegal norm value

norm

public static double norm(double x)

Get the L₂ norm (commonly known as the Euclidean norm) for the vector with the given components. This corresponds to the common notion of vector magnitude or length and is defined as the square root of the sum of the squares of all vector components.

Parameters:

x - vector component

Returns:

L₂ norm for the vector with the given components

See Also:

L2 Norm

norm

public static double norm(double x1,
                          double x2)

Get the L₂ norm (commonly known as the Euclidean norm) for the vector with the given components. This corresponds to the common notion of vector magnitude or length and is defined as the square root of the sum of the squares of all vector components.

Parameters:

x1 - first vector component

x2 - second vector component

Returns:

L₂ norm for the vector with the given components

See Also:

L2 Norm

norm

public static double norm(double x1,
                          double x2,
                          double x3)

Get the L₂ norm (commonly known as the Euclidean norm) for the vector with the given components. This corresponds to the common notion of vector magnitude or length and is defined as the square root of the sum of the squares of all vector components.

Parameters:

x1 - first vector component

x2 - second vector component

x3 - third vector component

Returns:

L₂ norm for the vector with the given components

See Also:

L2 Norm

normSq

public static double normSq(double x)

Get the square of the L₂ norm (also known as the Euclidean norm) for the vector with the given components. This is equal to the sum of the squares of all vector components.

Parameters:

x - vector component

Returns:

square of the L₂ norm for the vector with the given components

See Also:

norm(double)

normSq

public static double normSq(double x1,
                            double x2)

Get the square of the L₂ norm (also known as the Euclidean norm) for the vector with the given components. This is equal to the sum of the squares of all vector components.

Parameters:

x1 - first vector component

x2 - second vector component

Returns:

square of the L₂ norm for the vector with the given components

See Also:

norm(double, double)

normSq

public static double normSq(double x1,
                            double x2,
                            double x3)

Get the square of the L₂ norm (also known as the Euclidean norm) for the vector with the given components. This is equal to the sum of the squares of all vector components.

Parameters:

x1 - first vector component

x2 - second vector component

x3 - third vector component

Returns:

square of the L₂ norm for the vector with the given components

See Also:

norm(double, double, double)

linearCombination

public static double linearCombination(double a1,
                                       double b1,
                                       double a2,
                                       double b2)

Compute the linear combination \(a_1 b_1 + a_2 b_2 \) with high accuracy.

Parameters:

a1 - first factor of the first term

b1 - second factor of the first term

a2 - first factor of the second term

b2 - second factor of the seconf term

Returns:

linear combination.

See Also:

Sum

linearCombination

public static double linearCombination(double a1,
                                       double b1,
                                       double a2,
                                       double b2,
                                       double a3,
                                       double b3)

Compute the linear combination \(a_1 b_1 + a_2 b_2 + a_3 b_3 \) with high accuracy.

Parameters:

a1 - first factor of the first term

b1 - second factor of the first term

a2 - first factor of the second term

b2 - second factor of the seconf term

a3 - first factor of the third term

b3 - second factor of the third term

Returns:

linear combination.

See Also:

Sum