org.kabeja.math
Class MathUtils

java.lang.Object
  org.kabeja.math.MathUtils

public class MathUtils
extends java.lang.Object

Author:

Field Summary

static double

DISTANCE_DELTA

Constructor Summary

MathUtils()

Method Summary

static double	absoluteValue(Vector v) Returns the absalute value (or length) of the vector
static Vector	addVectorToVector(Vector a, Vector b)
static Vector	crossProduct(Vector a, Vector b) Calculate the cross product of 2 vectors.
static double	distance(Point start, Point end)
static double	getAngle(Vector a, Vector b) Calculate the angle between vector a vector b
static double	getDirectionAngle(Vector v) Returns the angle of the vector again the x-axis
static Point	getIntersection(Point a, Vector u, Point b, Vector v)
static Point	getPointOfStraightLine(Point a, Vector direction, double parameter) Calculate a point of a straigt line.
static int	getQuadrant(double angle) Returns the qaudrant for the given angle: 0,1,2 or 3
static int	getQuadrant(Point p, Point center) Returns the qaudrant: 0,1,2 or 3
static Vector	getVector(Point a, Point b) Calculate the vector from point a to point b
static Vector	invertDirection(Vector v) Invert the direction of the given vector
static double[][]	multiplyMatrixByMatrix(double[][] a, double[][] b)
static double[]	multiplyMatrixByVector(double[][] a, double[] v)
static Vector	normalize(Vector v)
static Point	rotatePointXY(Point p, Point center, double angle) Rotate the given point around centerpoint with the given angle in X-Y plane.
static double	scalarProduct(Vector a, Vector b) Calculate the scalar product of vector a and vector b
static Vector	scaleVector(Vector a, double scale) Scale a vector with the given value
static Vector	subtractVectorByVector(Vector a, Vector b) Substracts a vector from other vector.

Methods inherited from class java.lang.Object

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

Field Detail

DISTANCE_DELTA

public static final double DISTANCE_DELTA

See Also:

Constant Field Values

Constructor Detail

MathUtils

public MathUtils()

Method Detail

scalarProduct

public static double scalarProduct(Vector a,
                                   Vector b)

Calculate the scalar product of vector a and vector b

Parameters:

a -

b -

Returns:

the result of the scalar product

absoluteValue

public static double absoluteValue(Vector v)

Returns the absalute value (or length) of the vector

Parameters:

v -

Returns:

crossProduct

public static Vector crossProduct(Vector a,
                                  Vector b)

Calculate the cross product of 2 vectors.

Parameters:

a -

b -

Returns:

a new vector as result of the cross product of a and b

scaleVector

public static Vector scaleVector(Vector a,
                                 double scale)

Scale a vector with the given value

Parameters:

a - the vector

scale - the value to scale

Returns:

a new vector scaled with the given

getPointOfStraightLine

public static Point getPointOfStraightLine(Point a,
                                           Vector direction,
                                           double parameter)

Calculate a point of a straigt line.

Parameters:

a - the startpoint of the straight line

direction - the direction vector of the straight line

parameter - the parameter

Returns:

a new point

getVector

public static Vector getVector(Point a,
                               Point b)

Calculate the vector from point a to point b

Parameters:

a -

b -

Returns:

the vector from a to b

getIntersection

public static Point getIntersection(Point a,
                                    Vector u,
                                    Point b,
                                    Vector v)

distance

public static double distance(Point start,
                              Point end)

getAngle

public static double getAngle(Vector a,
                              Vector b)

Calculate the angle between vector a vector b

Parameters:

a -

b -

Returns:

the angle in radian

rotatePointXY

public static Point rotatePointXY(Point p,
                                  Point center,
                                  double angle)

Rotate the given point around centerpoint with the given angle in X-Y plane.

Parameters:

p - the point to rotate

center - the centerpoint

angle - in radian

Returns:

the rotated point

normalize

public static Vector normalize(Vector v)

getQuadrant

public static int getQuadrant(Point p,
                              Point center)

Returns the qaudrant:
0,1,2 or 3

Parameters:

p -

center -

Returns:

getQuadrant

public static int getQuadrant(double angle)

Returns the qaudrant for the given angle:
0,1,2 or 3

Parameters:

angle - in degree

Returns:

the quadrant

getDirectionAngle

public static double getDirectionAngle(Vector v)

Returns the angle of the vector again the x-axis

Parameters:

v - the vector

Returns:

the angle in degree

invertDirection

public static Vector invertDirection(Vector v)

Invert the direction of the given vector

Parameters:

the - vector to invert

Returns:

new inverted vector

multiplyMatrixByMatrix

public static double[][] multiplyMatrixByMatrix(double[][] a,
                                                double[][] b)
                                         throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

multiplyMatrixByVector

public static double[] multiplyMatrixByVector(double[][] a,
                                              double[] v)
                                       throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

subtractVectorByVector

public static Vector subtractVectorByVector(Vector a,
                                            Vector b)

Substracts a vector from other vector.

Parameters:

a - the minuend

b - the subtrahend

Returns:

the difference as vector

addVectorToVector

public static Vector addVectorToVector(Vector a,
                                       Vector b)