Package org.robwork.sdurw

Class Quaternionf

java.lang.Object

org.robwork.sdurw.Rotation3DVectorf

org.robwork.sdurw.Quaternionf

public class Quaternionf
extends Rotation3DVectorf

A Quaternion \mathbf{q}\in \mathbb{R}^4 a complex
number used to describe rotations in 3-dimensional space.
q_w+{\bf i}\ q_x+ {\bf j} q_y+ {\bf k}\ q_z

Quaternions can be added and multiplied in a similar way as usual
algebraic numbers. Though there are differences. Quaternion
multiplication is not commutative which means
Q\cdot P \neq P\cdot Q

Constructor Summary

Constructors

Constructor	Description
Quaternionf()	constuct Quaterinion of {0,0,0,1}
Quaternionf(float qx, float qy, float qz, float qw)	Creates a Quaternion
Quaternionf(long cPtr, boolean cMemoryOwn)
Quaternionf(Quaternionf quat)	Creates a Quaternion from another Quaternion
Quaternionf(Rotation3Df rot)	Extracts a Quaternion from Rotation matrix using setRotation(const rw::math::Rotation3D<R>& rot)

Method Summary

Modifier and Type	Method	Description
Quaternionf	add()	Unary plus.
void	delete()
EigenQuaternionf	e()	Convert to an Eigen Quaternion.
boolean	equals(Quaternionf r)	Comparison (equals) operator
float	get(long i)
static long	getCPtr(Quaternionf obj)
float	getLength()	get length of quaternion \sqrt{q_x^2+q_y^2+q_z^2+q_w^2}
float	getLengthSquared()	get squared length of quaternion q_x^2+q_y^2+q_z^2+q_w^2
float	getQw()	get method for the w component
float	getQx()	get method for the x component
float	getQy()	get method for the y component
float	getQz()	get method for the z component
Quaternionf	multiply(float s)	Scalar multiplication.
Quaternionf	negate()	Unary minus.
void	normalize()	normalizes this quaternion so that normalze(Q)=\frac{Q}{\sqrt{q_x^2+q_y^2+q_z^2+q_w^2}}
void	set(long i, float d)
long	size()	The dimension of the quaternion (i.e.
Quaternionf	slerp(Quaternionf v, float t)	Calculates a slerp interpolation between this and v. The slerp interpolation ensures a constant velocity across the interpolation. For t=0 the result is this and for t=1 it is v. Note: Algorithm and implementation is thanks to euclideanspace.com
Rotation3Df	toRotation3D()	Calculates the 3\times 3 Rotation matrix
java.lang.String	toString()

Methods inherited from class org.robwork.sdurw.Rotation3DVectorf

getCPtr

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Quaternionf

public Quaternionf(long cPtr,
                   boolean cMemoryOwn)

Quaternionf

public Quaternionf()

constuct Quaterinion of {0,0,0,1}

Quaternionf

public Quaternionf(float qx,
                   float qy,
                   float qz,
                   float qw)

Creates a Quaternion

Parameters:

qx - [in] q_x

qy - [in] q_y

qz - [in] q_z

qw - [in] q_w

Quaternionf

public Quaternionf(Quaternionf quat)

Creates a Quaternion from another Quaternion

Parameters:

quat - [in] Quaternion

Quaternionf

public Quaternionf(Rotation3Df rot)

Extracts a Quaternion from Rotation matrix using
setRotation(const rw::math::Rotation3D<R>& rot)

Parameters:

rot - [in] A 3x3 rotation matrix \mathbf{rot}

Method Detail

getCPtr

public static long getCPtr(Quaternionf obj)

delete

public void delete()

Overrides:

delete in class Rotation3DVectorf

getQx

public float getQx()

get method for the x component

Returns:

the x component of the quaternion

getQy

public float getQy()

get method for the y component

Returns:

the y component of the quaternion

getQz

public float getQz()

get method for the z component

Returns:

the z component of the quaternion

getQw

public float getQw()

get method for the w component

Returns:

the w component of the quaternion

getLength

public float getLength()

get length of quaternion
\sqrt{q_x^2+q_y^2+q_z^2+q_w^2}

Returns:

the length og this quaternion

getLengthSquared

public float getLengthSquared()

get squared length of quaternion
q_x^2+q_y^2+q_z^2+q_w^2

Returns:

the length og this quaternion

normalize

public void normalize()

normalizes this quaternion so that
normalze(Q)=\frac{Q}{\sqrt{q_x^2+q_y^2+q_z^2+q_w^2}}

toRotation3D

public Rotation3Df toRotation3D()

Calculates the 3\times 3 Rotation matrix

Overrides:

toRotation3D in class Rotation3DVectorf

Returns:

A 3x3 rotation matrix \mathbf{rot}
\mathbf{rot} = \left[ \begin{array}{ccc} 1-2(q_y^2-q_z^2) 2(q_x\ q_y+q_z\ q_w) 2(q_x\ q_z-q_y\ q_w) \\ 2(q_x\ q_y-q_z\ q_w) 1-2(q_x^2-q_z^2) 2(q_y\ q_z+q_x\ q_w)\\ 2(q_x\ q_z+q_y\ q_w) 2(q_y\ q_z-q_x\ q_z) 1-2(q_x^2-q_y^2) \end{array} \right]

size

public long size()

The dimension of the quaternion (i.e. 4).
This method is provided to help support generic algorithms using
size() and operator[].

slerp

public Quaternionf slerp(Quaternionf v,
                         float t)

Calculates a slerp interpolation between this and v.

The slerp interpolation ensures a constant velocity across the interpolation.
For t=0 the result is this and for t=1 it is v.

Note: Algorithm and implementation is thanks to euclideanspace.com

multiply

public Quaternionf multiply(float s)

Scalar multiplication.

negate

public Quaternionf negate()

Unary minus.

add

public Quaternionf add()

Unary plus.

equals

public boolean equals(Quaternionf r)

Comparison (equals) operator

e

public EigenQuaternionf e()

Convert to an Eigen Quaternion.

Returns:

Eigen Quaternion representation.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

get

public float get(long i)

set

public void set(long i,
                float d)