org.dolben.iiid
Class Rn

java.lang.Object
  org.dolben.iiid.Rn

public class Rn
extends java.lang.Object

These are collected functions on generic vectors and matrices.

A scalar is represented by a double. (gratuitous comment;-)

A vector is represented by a one dimensional array of doubles.

A matrix is represented by a two dimensional array of doubles where the row is indexed first.

None of these functions modify their arguments. A returned vector or matrix result is a new array.

Constructor Summary

Rn()

Method Summary

static double[]	add(double[] u, double[] v) Adds two vectors
static double	angle(double[] u, double[] v) Computes the angle between two vectors
static double	dot(double[] u, double[] v) Computes the dot product of two vectors
static double	magnitude(double[] v) Computes the magnitude of a vector
static double[]	multiply(double[][] a, double[] v) Multiplies a vector by a matrix
static double[][]	multiply(double[][] b, double[][] a) Multiplies two matrices
static double[]	multiply(double s, double[] v) Multiplies a vector by a scalar
static double[]	subtract(double[] u, double[] v) Subtracts one vector from another
static double[][]	transpose(double[][] a) Transposes a matrix

Methods inherited from class java.lang.Object

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

Constructor Detail

Rn

public Rn()

Method Detail

multiply

public static double[] multiply(double s,
                                double[] v)

Multiplies a vector by a scalar

Parameters:

s - a scalar

v - a vector

Returns:

the scaled vector

dot

public static double dot(double[] u,
                         double[] v)

Computes the dot product of two vectors

Parameters:

u - one vector

v - another vector

Returns:

the dot product

magnitude

public static double magnitude(double[] v)

Computes the magnitude of a vector

Parameters:

v - a vector

Returns:

the magnitude

angle

public static double angle(double[] u,
                           double[] v)

Computes the angle between two vectors

Parameters:

u - one vector

v - another vector

Returns:

the angle in radians

add

public static double[] add(double[] u,
                           double[] v)

Adds two vectors

Parameters:

u - one vector

v - another vector

Returns:

the vector sum

subtract

public static double[] subtract(double[] u,
                                double[] v)

Subtracts one vector from another

Parameters:

u - another vector

v - one vector

Returns:

the vector difference, u-v

multiply

public static double[] multiply(double[][] a,
                                double[] v)

Multiplies a vector by a matrix

Parameters:

a - the matrix

v - the vector

Returns:

the transformed vector

multiply

public static double[][] multiply(double[][] b,
                                  double[][] a)

Multiplies two matrices

Parameters:

b - one matrix

a - another matrix

Returns:

the matrix product

transpose

public static double[][] transpose(double[][] a)

Transposes a matrix

Parameters:

a - a matrix

Returns:

the transpose