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SUMMARY: NESTED  FIELD  CONSTR  METHOD  DETAIL: FIELD  CONSTR  METHOD 
java.lang.Object org.apache.commons.math3.geometry.euclidean.threed.FieldRotation<T>
T
 the type of the field elementspublic class FieldRotation<T extends RealFieldElement<T>>
This class is a reimplementation of Rotation
using RealFieldElement
.
Instance of this class are guaranteed to be immutable.
FieldVector3D
,
RotationOrder
,
Serialized FormConstructor Summary  

FieldRotation(FieldVector3D<T> u,
FieldVector3D<T> v)
Build one of the rotations that transform one vector into another one. 

FieldRotation(FieldVector3D<T> u1,
FieldVector3D<T> u2,
FieldVector3D<T> v1,
FieldVector3D<T> v2)
Build the rotation that transforms a pair of vector into another pair. 

FieldRotation(FieldVector3D<T> axis,
T angle)
Build a rotation from an axis and an angle. 

FieldRotation(RotationOrder order,
T alpha1,
T alpha2,
T alpha3)
Build a rotation from three Cardan or Euler elementary rotations. 

FieldRotation(T[][] m,
double threshold)
Build a rotation from a 3X3 matrix. 

FieldRotation(T q0,
T q1,
T q2,
T q3,
boolean needsNormalization)
Build a rotation from the quaternion coordinates. 
Method Summary  

void 
applyInverseTo(double[] in,
T[] out)
Apply the inverse of the rotation to a vector stored in an array. 

FieldRotation<T> 
applyInverseTo(FieldRotation<T> r)
Apply the inverse of the instance to another rotation. 

FieldVector3D<T> 
applyInverseTo(FieldVector3D<T> u)
Apply the inverse of the rotation to a vector. 

FieldRotation<T> 
applyInverseTo(Rotation r)
Apply the inverse of the instance to another rotation. 

static

applyInverseTo(Rotation rOuter,
FieldRotation<T> rInner)
Apply the inverse of a rotation to another rotation. 

static

applyInverseTo(Rotation r,
FieldVector3D<T> u)
Apply the inverse of a rotation to a vector. 

void 
applyInverseTo(T[] in,
T[] out)
Apply the inverse of the rotation to a vector stored in an array. 

FieldVector3D<T> 
applyInverseTo(Vector3D u)
Apply the inverse of the rotation to a vector. 

void 
applyTo(double[] in,
T[] out)
Apply the rotation to a vector stored in an array. 

FieldRotation<T> 
applyTo(FieldRotation<T> r)
Apply the instance to another rotation. 

FieldVector3D<T> 
applyTo(FieldVector3D<T> u)
Apply the rotation to a vector. 

FieldRotation<T> 
applyTo(Rotation r)
Apply the instance to another rotation. 

static

applyTo(Rotation r1,
FieldRotation<T> rInner)
Apply a rotation to another rotation. 

static

applyTo(Rotation r,
FieldVector3D<T> u)
Apply a rotation to a vector. 

void 
applyTo(T[] in,
T[] out)
Apply the rotation to a vector stored in an array. 

FieldVector3D<T> 
applyTo(Vector3D u)
Apply the rotation to a vector. 

static

distance(FieldRotation<T> r1,
FieldRotation<T> r2)
Compute the distance between two rotations. 

T 
getAngle()
Get the angle of the rotation. 

T[] 
getAngles(RotationOrder order)
Get the Cardan or Euler angles corresponding to the instance. 

FieldVector3D<T> 
getAxis()
Get the normalized axis of the rotation. 

T[][] 
getMatrix()
Get the 3X3 matrix corresponding to the instance 

T 
getQ0()
Get the scalar coordinate of the quaternion. 

T 
getQ1()
Get the first coordinate of the vectorial part of the quaternion. 

T 
getQ2()
Get the second coordinate of the vectorial part of the quaternion. 

T 
getQ3()
Get the third coordinate of the vectorial part of the quaternion. 

FieldRotation<T> 
revert()
Revert a rotation. 

Rotation 
toRotation()
Convert to a constant vector without derivatives. 
Methods inherited from class java.lang.Object 

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

public FieldRotation(T q0, T q1, T q2, T q3, boolean needsNormalization)
A rotation can be built from a normalized quaternion, i.e. a quaternion for which q_{0}^{2} + q_{1}^{2} + q_{2}^{2} + q_{3}^{2} = 1. If the quaternion is not normalized, the constructor can normalize it in a preprocessing step.
Note that some conventions put the scalar part of the quaternion as the 4^{th} component and the vector part as the first three components. This is not our convention. We put the scalar part as the first component.
q0
 scalar part of the quaternionq1
 first coordinate of the vectorial part of the quaternionq2
 second coordinate of the vectorial part of the quaternionq3
 third coordinate of the vectorial part of the quaternionneedsNormalization
 if true, the coordinates are considered
not to be normalized, a normalization preprocessing step is performed
before using thempublic FieldRotation(FieldVector3D<T> axis, T angle) throws MathIllegalArgumentException
We use the convention that angles are oriented according to
the effect of the rotation on vectors around the axis. That means
that if (i, j, k) is a direct frame and if we first provide +k as
the axis and π/2 as the angle to this constructor, and then
apply
the instance to +i, we will get
+j.
Another way to represent our convention is to say that a rotation of angle θ about the unit vector (x, y, z) is the same as the rotation build from quaternion components { cos(θ/2), x * sin(θ/2), y * sin(θ/2), z * sin(θ/2) }. Note the minus sign on the angle!
On the one hand this convention is consistent with a vectorial perspective (moving vectors in fixed frames), on the other hand it is different from conventions with a frame perspective (fixed vectors viewed from different frames) like the ones used for example in spacecraft attitude community or in the graphics community.
axis
 axis around which to rotateangle
 rotation angle.
MathIllegalArgumentException
 if the axis norm is zeropublic FieldRotation(T[][] m, double threshold) throws NotARotationMatrixException
Rotation matrices are orthogonal matrices, i.e. unit matrices (which are matrices for which m.m^{T} = I) with real coefficients. The module of the determinant of unit matrices is 1, among the orthogonal 3X3 matrices, only the ones having a positive determinant (+1) are rotation matrices.
When a rotation is defined by a matrix with truncated values (typically when it is extracted from a technical sheet where only four to five significant digits are available), the matrix is not orthogonal anymore. This constructor handles this case transparently by using a copy of the given matrix and applying a correction to the copy in order to perfect its orthogonality. If the Frobenius norm of the correction needed is above the given threshold, then the matrix is considered to be too far from a true rotation matrix and an exception is thrown.
m
 rotation matrixthreshold
 convergence threshold for the iterative
orthogonality correction (convergence is reached when the
difference between two steps of the Frobenius norm of the
correction is below this threshold)
NotARotationMatrixException
 if the matrix is not a 3X3
matrix, or if it cannot be transformed into an orthogonal matrix
with the given threshold, or if the determinant of the resulting
orthogonal matrix is negativepublic FieldRotation(FieldVector3D<T> u1, FieldVector3D<T> u2, FieldVector3D<T> v1, FieldVector3D<T> v2) throws MathArithmeticException
Except for possible scale factors, if the instance were applied to the pair (u_{1}, u_{2}) it will produce the pair (v_{1}, v_{2}).
If the angular separation between u_{1} and u_{2} is not the same as the angular separation between v_{1} and v_{2}, then a corrected v'_{2} will be used rather than v_{2}, the corrected vector will be in the (v_{1}, v_{2}) plane.
u1
 first vector of the origin pairu2
 second vector of the origin pairv1
 desired image of u1 by the rotationv2
 desired image of u2 by the rotation
MathArithmeticException
 if the norm of one of the vectors is zero,
or if one of the pair is degenerated (i.e. the vectors of the pair are colinear)public FieldRotation(FieldVector3D<T> u, FieldVector3D<T> v) throws MathArithmeticException
Except for a possible scale factor, if the instance were applied to the vector u it will produce the vector v. There is an infinite number of such rotations, this constructor choose the one with the smallest associated angle (i.e. the one whose axis is orthogonal to the (u, v) plane). If u and v are colinear, an arbitrary rotation axis is chosen.
u
 origin vectorv
 desired image of u by the rotation
MathArithmeticException
 if the norm of one of the vectors is zeropublic FieldRotation(RotationOrder order, T alpha1, T alpha2, T alpha3)
Cardan rotations are three successive rotations around the canonical axes X, Y and Z, each axis being used once. There are 6 such sets of rotations (XYZ, XZY, YXZ, YZX, ZXY and ZYX). Euler rotations are three successive rotations around the canonical axes X, Y and Z, the first and last rotations being around the same axis. There are 6 such sets of rotations (XYX, XZX, YXY, YZY, ZXZ and ZYZ), the most popular one being ZXZ.
Beware that many people routinely use the term Euler angles even for what really are Cardan angles (this confusion is especially widespread in the aerospace business where Roll, Pitch and Yaw angles are often wrongly tagged as Euler angles).
order
 order of rotations to usealpha1
 angle of the first elementary rotationalpha2
 angle of the second elementary rotationalpha3
 angle of the third elementary rotationMethod Detail 

public FieldRotation<T> revert()
public T getQ0()
public T getQ1()
public T getQ2()
public T getQ3()
public FieldVector3D<T> getAxis()
FieldRotation(FieldVector3D, RealFieldElement)
public T getAngle()
FieldRotation(FieldVector3D, RealFieldElement)
public T[] getAngles(RotationOrder order) throws CardanEulerSingularityException
The equations show that each rotation can be defined by two different values of the Cardan or Euler angles set. For example if Cardan angles are used, the rotation defined by the angles a_{1}, a_{2} and a_{3} is the same as the rotation defined by the angles π + a_{1}, π  a_{2} and π + a_{3}. This method implements the following arbitrary choices:
Cardan and Euler angle have a very disappointing drawback: all of them have singularities. This means that if the instance is too close to the singularities corresponding to the given rotation order, it will be impossible to retrieve the angles. For Cardan angles, this is often called gimbal lock. There is nothing to do to prevent this, it is an intrinsic problem with Cardan and Euler representation (but not a problem with the rotation itself, which is perfectly well defined). For Cardan angles, singularities occur when the second angle is close to π/2 or +π/2, for Euler angle singularities occur when the second angle is close to 0 or π, this implies that the identity rotation is always singular for Euler angles!
order
 rotation order to use
CardanEulerSingularityException
 if the rotation is
singular with respect to the angles set specifiedpublic T[][] getMatrix()
public Rotation toRotation()
public FieldVector3D<T> applyTo(FieldVector3D<T> u)
u
 vector to apply the rotation to
public FieldVector3D<T> applyTo(Vector3D u)
u
 vector to apply the rotation to
public void applyTo(T[] in, T[] out)
in
 an array with three items which stores vector to rotateout
 an array with three items to put result to (it can be the same
array as in)public void applyTo(double[] in, T[] out)
in
 an array with three items which stores vector to rotateout
 an array with three items to put result topublic static <T extends RealFieldElement<T>> FieldVector3D<T> applyTo(Rotation r, FieldVector3D<T> u)
T
 the type of the field elementsr
 rotation to applyu
 vector to apply the rotation to
public FieldVector3D<T> applyInverseTo(FieldVector3D<T> u)
u
 vector to apply the inverse of the rotation to
public FieldVector3D<T> applyInverseTo(Vector3D u)
u
 vector to apply the inverse of the rotation to
public void applyInverseTo(T[] in, T[] out)
in
 an array with three items which stores vector to rotateout
 an array with three items to put result to (it can be the same
array as in)public void applyInverseTo(double[] in, T[] out)
in
 an array with three items which stores vector to rotateout
 an array with three items to put result topublic static <T extends RealFieldElement<T>> FieldVector3D<T> applyInverseTo(Rotation r, FieldVector3D<T> u)
T
 the type of the field elementsr
 rotation to applyu
 vector to apply the inverse of the rotation to
public FieldRotation<T> applyTo(FieldRotation<T> r)
r
 rotation to apply the rotation to
public FieldRotation<T> applyTo(Rotation r)
r
 rotation to apply the rotation to
public static <T extends RealFieldElement<T>> FieldRotation<T> applyTo(Rotation r1, FieldRotation<T> rInner)
T
 the type of the field elementsr1
 rotation to applyrInner
 rotation to apply the rotation to
public FieldRotation<T> applyInverseTo(FieldRotation<T> r)
r
 rotation to apply the rotation to
public FieldRotation<T> applyInverseTo(Rotation r)
r
 rotation to apply the rotation to
public static <T extends RealFieldElement<T>> FieldRotation<T> applyInverseTo(Rotation rOuter, FieldRotation<T> rInner)
T
 the type of the field elementsrOuter
 rotation to apply the rotation torInner
 rotation to apply the rotation to
public static <T extends RealFieldElement<T>> T distance(FieldRotation<T> r1, FieldRotation<T> r2)
The distance is intended here as a way to check if two rotations are almost similar (i.e. they transform vectors the same way) or very different. It is mathematically defined as the angle of the rotation r that prepended to one of the rotations gives the other one:
r_{1}(r) = r_{2}
This distance is an angle between 0 and π. Its value is the smallest possible upper bound of the angle in radians between r_{1}(v) and r_{2}(v) for all possible vectors v. This upper bound is reached for some v. The distance is equal to 0 if and only if the two rotations are identical.
Comparing two rotations should always be done using this value rather than for example comparing the components of the quaternions. It is much more stable, and has a geometric meaning. Also comparing quaternions components is error prone since for example quaternions (0.36, 0.48, 0.48, 0.64) and (0.36, 0.48, 0.48, 0.64) represent exactly the same rotation despite their components are different (they are exact opposites).
T
 the type of the field elementsr1
 first rotationr2
 second rotation


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