org.moeaframework.util
Class RotationMatrixBuilder

java.lang.Object
  org.moeaframework.util.RotationMatrixBuilder

public class RotationMatrixBuilder
extends Object

Builds rotation matrices of any dimension constructively from one or more 2D planar rotations. Three types of construction mechanisms are provided:

1. Specific rotation planes and thetas

     new RotationMatrixBuilder(3).rotatePlane(0,1).withTheta(Math.PI/4)
          .rotatePlane(1,2).withTheta(Math.PI/8).create()

2. Specific rotation planes with random thetas

     new RotationMatrixBuilder(3).rotatePlane(0,1).rotatePlane(1,2)
          .withRandomThetas().create()

3. Random subplanes with random thetas

     new RotationMatrixBuilder(3).rotateK(2).create()

References:

1. Aguilera, A. and Pérez-Aguila, R. "General n-Dimensional Rotations." WSCG 2004, pp. 1-8, 2004.

Constructor Summary

RotationMatrixBuilder(int dimension)
Constructs a rotation matrix builder for the given dimension.

Method Summary

org.apache.commons.math3.linear.RealMatrix	create() Returns the rotation matrix resulting from applying all 2D rotation planes and angles added to this builder.
RotationMatrixBuilder	rotateAll() Rotates all 2D rotation planes and assigns each a random rotation angle.
RotationMatrixBuilder	rotateK(int k) Rotates k randomly-selected but unique 2D rotation planes and assigns each a random rotation angle.
RotationMatrixBuilder	rotatePlane(int i, int j) Adds a rotation around the 2D rotation plane defined by the two axes.
RotationMatrixBuilder	withRandomThetas() Assigns random rotation angles to all 2D rotation planes added to this builder.
RotationMatrixBuilder	withTheta(double theta) Sets the rotation angle, in radians, of the last 2D rotation plane added to this builder.
RotationMatrixBuilder	withThetas(double theta) Sets the rotation angle, in radians, of all 2D rotation planes added to this builder.

Methods inherited from class java.lang.Object

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

Constructor Detail

RotationMatrixBuilder

public RotationMatrixBuilder(int dimension)

Constructs a rotation matrix builder for the given dimension.

Parameters:

dimension - the dimension of rotation matrices produced by this builder

Method Detail

rotatePlane

public RotationMatrixBuilder rotatePlane(int i,
                                         int j)

Adds a rotation around the 2D rotation plane defined by the two axes. The plane is initially unrotated, but can be assigned a specific rotation angle if followed by withTheta(double).

Parameters:

i - the first axis

j - the second axis

Returns:

a reference to this rotation matrix builder

withTheta

public RotationMatrixBuilder withTheta(double theta)

Sets the rotation angle, in radians, of the last 2D rotation plane added to this builder. This method should always only follow invocations of rotatePlane(int, int).

Parameters:

theta - the rotation angle in radians

Returns:

a reference to this rotation matrix builder

withThetas

public RotationMatrixBuilder withThetas(double theta)

Sets the rotation angle, in radians, of all 2D rotation planes added to this builder.

Parameters:

theta - the rotation angle in radians

Returns:

a reference to this rotation matrix builder

withRandomThetas

public RotationMatrixBuilder withRandomThetas()

Assigns random rotation angles to all 2D rotation planes added to this builder.

Returns:

a reference to this rotation matrix builder

rotateAll

public RotationMatrixBuilder rotateAll()

Rotates all 2D rotation planes and assigns each a random rotation angle.

Returns:

a reference to this rotation matrix builder

rotateK

public RotationMatrixBuilder rotateK(int k)

Rotates k randomly-selected but unique 2D rotation planes and assigns each a random rotation angle. For an N-dimension rotation matrix, there exist (N choose 2) 2D rotation planes.

Parameters:

k - the number of randomly-selected 2D rotation planes

Returns:

a reference to this rotation matrix builder

create

public org.apache.commons.math3.linear.RealMatrix create()

Returns the rotation matrix resulting from applying all 2D rotation planes and angles added to this builder.

Returns:

the rotation matrix resulting from applying all 2D rotation planes and angles added to this builder