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In [[numerical linear algebra]], a '''Givens rotation''' is a [[Rotation (mathematics)|rotation]] in the plane spanned by two coordinates axes. Givens rotations are named after [[Wallace Givens]], who introduced them to numerical analysts in the 1950s while he was working at [[Argonne National Laboratory]]. | |||
== Matrix representation == | |||
The | A Givens rotation is represented by a [[matrix (mathematics)|matrix]] of the form | ||
:<math>G(i, j, \theta) = | |||
\begin{bmatrix} 1 & \cdots & 0 & \cdots & 0 & \cdots & 0 \\ | |||
\vdots & \ddots & \vdots & & \vdots & & \vdots \\ | |||
0 & \cdots & c & \cdots & -s & \cdots & 0 \\ | |||
\vdots & & \vdots & \ddots & \vdots & & \vdots \\ | |||
0 & \cdots & s & \cdots & c & \cdots & 0 \\ | |||
\vdots & & \vdots & & \vdots & \ddots & \vdots \\ | |||
0 & \cdots & 0 & \cdots & 0 & \cdots & 1 | |||
\end{bmatrix}</math> | |||
where ''c'' = cos(''θ'') and ''s'' = sin(''θ'') appear at the intersections ''i''th and ''j''th rows and columns. That is, the non-zero elements of Givens matrix is given by: | |||
:<math>\begin{align} | |||
g_{k\, k} &{}= 1 \qquad \text{for} \ k \ne i,\,j\\ | |||
g_{i\, i} &{}= c \\ | |||
g_{j\, j} &{}= c \\ | |||
g_{j\, i} &{}= -s \\ | |||
g_{i\, j} &{}= s \qquad \text{for} \ i > j | |||
\end{align}</math> (sign of sine switches for j > i) | |||
The product ''G''(''i'',''j'',θ)'''x''' represents a counterclockwise rotation | |||
of the vector '''x''' in the (''i'',''j'') plane of θ radians, hence the name Givens rotation. | |||
The main use of Givens rotations in [[numerical linear algebra]] is to introduce zeros in vectors or matrices. | |||
This effect can, for example, be employed for computing the [[QR decomposition]] of a matrix. One advantage over [[Householder transformation]]s is that they can easily be parallelised, and another is that often for very sparse matrices they have a lower operation count. | |||
== Stable calculation == | |||
When a Givens rotation matrix, ''G''(''i'',''j'',θ), multiplies another matrix, ''A'', from the left, ''GA'', only rows ''i'' and ''j'' of ''A'' are affected. Thus we restrict attention to the following problem. Given ''a'' and ''b'', find ''c'' = cos θ and ''s'' = sin θ such that | |||
:<math> \begin{bmatrix} c & -s \\ s & c \end{bmatrix} \begin{bmatrix} a \\ b \end{bmatrix} = \begin{bmatrix} r \\ 0 \end{bmatrix} . </math> | |||
Explicit calculation of θ is rarely necessary or desirable. Instead we directly seek ''c'', ''s'', and ''r''. An obvious solution would be | |||
:<math>\begin{align} | |||
r &{}\larr \sqrt{a^2 + b^2} \\ | |||
c &{}\larr a / r \\ | |||
s &{}\larr -b / r. | |||
\end{align}</math> | |||
However, the computation for ''r'' may [[arithmetic overflow|overflow]] or underflow. An alternative formulation avoiding this problem {{harv|Golub|Van Loan|1996|loc=§5.1.8}} is implemented as the [[hypot]] function in many programming languages . | |||
Furthermore, as {{harvtxt|Anderson|2000}} discovered in improving [[LAPACK]], a previously overlooked numerical consideration is continuity. To achieve this, we require ''r'' to be positive. | |||
if (b = 0) then {c ← copysign(1,a); s ← 0; r ← abs(a)} | |||
else if (a = 0) then {c ← 0; s ← -copysign(1,b); r ← abs(b)} | |||
else if (abs(b) > abs(a)) then | |||
t ← a/b | |||
u ← copysign(sqrt(1+t*t),b) | |||
s ← -1/u | |||
c ← -s*t | |||
r ← b*u | |||
else | |||
t ← b/a | |||
u ← copysign(sqrt(1+t*t),a) | |||
c ← 1/u | |||
s ← -c*t | |||
r ← a*u | |||
This is written in terms of the [[IEEE 754]] <tt>copysign(x,y)</tt> function, which provides a safe and cheap way to copy the sign of <tt>y</tt> to <tt>x</tt>. If that is not available, <tt>|x|*sgn(y)</tt>, using the [[sign function]], is an alternative. | |||
== Triangularization == | |||
Given the following 3x3 Matrix, perform two iterations of the Given's Rotation to bring the matrix to an upper [[Triangular matrix]] in order to compute the [[QR decomposition]]. | |||
:<math> A = | |||
\begin{bmatrix} 6 & 5 & 0 \\ | |||
5 & 1 & 4 \\ | |||
0 & 4 & 3 \\ | |||
\end{bmatrix}</math> | |||
In order to form the desired matrix, we must zero elements (2,1) and (3,2). We first select element (2,1) to zero. Using a rotation matrix of: | |||
:<math>G_{1} = | |||
\begin{bmatrix} c & -s & 0 \\ | |||
s & c & 0 \\ | |||
0 & 0 & 1 \\ | |||
\end{bmatrix}</math> | |||
We have the following matrix multiplication: | |||
:<math>\begin{bmatrix} c & -s & 0 \\ | |||
s & c & 0 \\ | |||
0 & 0 & 1 \\ | |||
\end{bmatrix} | |||
\begin{bmatrix} 6 & 5 & 0 \\ | |||
5 & 1 & 4 \\ | |||
0 & 4 & 3 \\ | |||
\end{bmatrix}</math> | |||
Where: | |||
:<math>\begin{align} | |||
r &{}= \sqrt{6^2 + 5^2} = 7.8102 \\ | |||
c &{}= 6 / r = 0.7682\\ | |||
s &{}= -5 / r = -0.6402 | |||
\end{align} | |||
</math> | |||
Plugging in these values for c and s and performing the matrix multiplication above yields a new A of: | |||
:<math>A =\begin{bmatrix} 7.8102 & 4.4813 & 2.5607 \\ | |||
0 & -2.4327 & 3.0729 \\ | |||
0 & 4 & 3 \\ | |||
\end{bmatrix}</math> | |||
We now want to zero element (3,2) to finish off the process. Using the same idea as before, we have a rotation matrix of: | |||
:<math>G_{2} = | |||
\begin{bmatrix} 1 & 0 & 0 \\ | |||
0 & c & -s \\ | |||
0 & s & c \\ | |||
\end{bmatrix}</math> | |||
We are presented with the following matrix multiplication: | |||
:<math>\begin{bmatrix} 1 & 0 & 0 \\ | |||
0 & c & -s \\ | |||
0 & s & c \\ | |||
\end{bmatrix} | |||
\begin{bmatrix} 7.8102 & 4.4813 & 2.5607 \\ | |||
0 & -2.4327 & 3.0729 \\ | |||
0 & 4 & 3 \\ | |||
\end{bmatrix}</math> | |||
Where: | |||
:<math>\begin{align} | |||
r &{}= \sqrt{(-2.4327)^2 + 4^2} = 4.6817 \\ | |||
c &{}= -2.4327 / r = -0.5196 \\ | |||
s &{}= -4 / r = -0.8544 | |||
\end{align} | |||
</math> | |||
Plugging in these values for c and s and performing the multiplications gives us a new matrix of: | |||
:<math>R = | |||
\begin{bmatrix} 7.8102 & 4.4813 & 2.5607 \\ | |||
0 & 4.6817 & 0.9664 \\ | |||
0 & 0 & -4.1843 \\ | |||
\end{bmatrix}</math> | |||
This new matrix R is the upper triangular matrix needed to perform an iteration of the [[QR decomposition]]. Q is now formed using the transpose of the rotation matrices in the following manner: | |||
:<math>Q = G_{1}^T * G_{2}^T | |||
</math> | |||
Performing this matrix multiplication yields: | |||
:<math>Q = | |||
\begin{bmatrix} 0.7682 & 0.3327 & 0.5470 \\ | |||
0.6402 & -0.3992 & -0.6564 \\ | |||
0 & 0.8544 & -0.5196 \\ | |||
\end{bmatrix}</math> | |||
This completes two iterations of the Givens Rotation and calculating the [[QR decomposition]] can now be done. | |||
==Givens rotations in Clifford Algebras== | |||
In [[Clifford algebras]] and its child structures like [[geometric algebra]] rotations are represented by bivectors. Givens rotations are represented by the external product of the basis vectors. Given any pair of basis vectors <math>e_i, e_j</math> Givens rotations bivectors are: | |||
<math>B_{ij}=e_i\wedge e_j</math> | |||
Their action on any vector is written : | |||
<math>v=e^{-(\theta/2)(e_i \wedge e_j)}u e^{(\theta/2)(e_i \wedge e_j)}</math> | |||
where : | |||
<math>e^{(\theta/2)(e_i \wedge e_j)}= \cos(\theta/2)+ \sin(\theta/2) e_i \wedge e_j</math> | |||
==Dimension 3== | |||
:See also [[Euler angles]] | |||
There are three Givens rotations in dimension 3: | |||
:<math>\begin{align} \\ | |||
R_X(\theta) = | |||
\begin{bmatrix} | |||
1 & 0 & 0 \\ | |||
0 & \cos \theta & -\sin \theta \\ | |||
0 & \sin \theta & \cos \theta | |||
\end{bmatrix} | |||
\end{align} | |||
</math> | |||
Note: The <math>R_Y(\theta)</math> matrix immediately below is __not__ a Givens rotation. The <math>R_Y(\theta)</math> matrix immediately below respects the right-hand rule ... and is this usual matrix one sees in Computer Graphics; however, a Givens rotation is simply a matrix as defined in the [[#Matrix_representation|Matrix representation]] section above and does not necessarily respect the right-hand rule. This section should be considered suspect. | |||
:<math>\begin{align} \\ | |||
R_Y(\theta) = | |||
\begin{bmatrix} | |||
\cos \theta & 0 & \sin \theta \\ | |||
0 & 1 & 0 \\ | |||
-\sin \theta & 0 & \cos \theta | |||
\end{bmatrix} | |||
\end{align} | |||
</math> | |||
Note: The actual Givens rotation matrix for <math>R_Y(\theta)</math> would be: | |||
:<math>\begin{align} \\ | |||
R_Y(\theta) = | |||
\begin{bmatrix} | |||
\cos \theta & 0 & -\sin \theta \\ | |||
0 & 1 & 0 \\ | |||
\sin \theta & 0 & \cos \theta | |||
\end{bmatrix} | |||
\end{align} | |||
</math> | |||
:<math>\begin{align} \\ | |||
R_Z(\theta) = | |||
\begin{bmatrix} | |||
\cos \theta & -\sin \theta & 0 \\ | |||
\sin \theta & \cos \theta & 0 \\ | |||
0 & 0 & 1 | |||
\end{bmatrix} | |||
\end{align} | |||
</math> | |||
Given that they are [[endomorphism]]s they can be composed with each other as many times as desired, keeping in mind that ''g'' ∘ ''f'' ≠ ''f'' ∘ ''g''. | |||
These three '''Givens rotations''' [[Function composition#Rotation composition|composed]] can generate any rotation matrix. This means that they can [[transformation (geometry)|transform]] the basis of the space to any other [[Cartesian coordinate system|frame]] in the space. | |||
When rotations are performed in the right order, the values of the rotation angles of the final frame will be equal to the [[Euler angles]] of the final frame in the corresponding convention. For example, an operator <math>R = R_Y(\theta_3).R_X(\theta_2).R_Z(\theta_1)</math> transforms the basis of the space into a frame with angles roll, pitch and yaw <math>YPR = (\theta_3,\theta_2,\theta_1)</math> in the [[Euler angles#Tait–Bryan angles|Tait-Bryan convention]] z-x-y (convention in which the line of nodes is perpendicular to z and Y axes, also named Y-X’-Z’’). | |||
For the same reason, any [[rotation matrix]] in 3D can be decomposed in a product of three of these [[Rotation operator (vector space)|rotations]]. | |||
The meaning of the composition of two Givens rotations g∘f is an operator that transforms vectors first by f and then by g, being f and g rotations about one axis of basis of the space. This is similar to the [[Euler angles#Euler angles as composition of extrinsic rotations|extrinsic rotation equivalence]] for Euler angles. | |||
===Table of composed rotations=== | |||
The following table shows the three Givens rotations equivalent to the different Euler angles conventions using extrinsic composition (composition of rotations about the basis axes) of [[Active and passive transformation|active rotations]] and the right-handed rule for the positive sign of the angles. | |||
The notation has been simplified in such a way that c1 means cos(θ<sub>1</sub>) and s2 means sin(θ<sub>2</sub>). The subindexes of the angles are the order in which they are applied using '''extrinsic''' composition (1 for intrinsic rotation, 2 for nutation, 3 for precession) | |||
As rotations are applied just in the opposite order of the [[Euler angles#Table of composed rotations|Euler angles table of rotations]], this table is the same but swapping indexes 1 and 3 in the angles associated with the corresponding entry. An entry like zxy means to apply first the y rotation, then x, and finally z, in the basis axes. | |||
All the compositions assume the right hand convention for the matrices that are multiplied, yielding the following results<ref>[http://www.aeroengineering.info/eulermatrix.html Rotation matrix multiplication tool]</ref> | |||
:{| class="wikitable" style="background-color:white;font-weight:bold" | |||
|- | |||
!xzx | |||
|<math>\begin{bmatrix} | |||
c_2 & - c_1 s_2 & s_1 s_2 \\ | |||
c_3 s_2 & c_3 c_2 c_1 - s_3 s_1 & - c_2 c_3 s_1 - c_1 s_3 \\ | |||
s_2 s_3 & c_3 s_1 + c_1 c_2 s_3 & c_3 c_1 - c_2 s_3 s_1 | |||
\end{bmatrix}</math> | |||
!xzy | |||
|<math>\begin{bmatrix} | |||
c_2 c_3 & - c_3 s_2 c_1 + s_3 s_1 & c_3 s_2 s_1 + s_3 c_1 \\ | |||
s_2 & c_1 c_2 & - c_2 s_1 \\ | |||
- s_3 c_2 & s_3 s_2 c_1+c_3 s_1 & -s_3 s_2 s_1 + c_3 c_1 | |||
\end{bmatrix}</math> | |||
|- | |||
!xyx | |||
|<math>\begin{bmatrix} | |||
c_2 & s_1 s_2 & c_1 s_2 \\ | |||
s_2 s_3 & c_3 c_1 - c_2 s_3 s_1 & - c_3 s_1 - c_1 c_2 s_3 \\ | |||
-c_3 s_2 & c_3 c_2 s_1 + c_1 s_3 & c_3 c_2 c_1 - s_3 s_1 | |||
\end{bmatrix}</math> | |||
!xyz | |||
|<math>\begin{bmatrix} | |||
c_3 c_2 & -s_3 c_1 + c_3 s_2 s_1 & s_3 s_1 + c_3 s_2 c_1 \\ | |||
s_3 c_2 & c_3 c_1 + s_3 s_2 s_1 & -c_3 s_1 + s_3 s_2 c_1 \\ | |||
-s_2 & c_2 s_1 & c_2 c_1 | |||
\end{bmatrix}</math> | |||
|- | |||
!yxy | |||
|<math>\begin{bmatrix} | |||
c_3 c_1 - c_2 s_3 s_1 & s_2 s_3 & c_3 s_1 + s_3 c_2 c_1 \\ | |||
s_1 s_2 & c_2 & - c_1 s_2 \\ | |||
-c_2 c_3 s_1 - c_1 s_3 & c_3 s_2 & c_3 c_2 c_1 - s_3 s_1 | |||
\end{bmatrix}</math> | |||
!yxz | |||
|<math>\begin{bmatrix} | |||
c_3 c_1-s_3 s_2 s_1 & -s_3 c_2 & c_3 s_1+s_3 s_2 c_1 \\ | |||
s_3 c_1+c_3 s_2 s_1 & c_3 c_2 & s_3 s_1-c_3 s_2 c_1 \\ | |||
-c_2 s_1 & s_2 & c_2 c_1 | |||
\end{bmatrix}</math> | |||
|- | |||
!yxy | |||
|<math>\begin{bmatrix} | |||
c_3 c_2 c_1 - s_3 s_1 & - c_3 s_2 & c_2 c_3 s_1 + c_1 s_3 \\ | |||
c_1 s_2 & c_2 & s_1 s_2 \\ | |||
-c_3 s_1 - c_1 c_2 s_3 & s_2 s_3 & c_3 c_1 - c_2 s_3 s_1 | |||
\end{bmatrix}</math> | |||
!yzx | |||
|<math>\begin{bmatrix} | |||
c_2 c_1 & -s_2 & c_2 s_1 \\ | |||
c_3 s_2 c_1+s_3 s_1 & c_3 c_2 & c_3 s_2 s_1-s_3 c_1 \\ | |||
s_3 s_2 c_1-c_3 s_1 & s_3 c_2 & s_3 s_2 s_1+c_3 c_1 | |||
\end{bmatrix}</math> | |||
|- | |||
!zyz | |||
|<math>\begin{bmatrix} | |||
c_3 c_2 c_1 - s_3 s_1 & - c_2 s_1 c_3 - c_1 s_3 & c_3 s_2 \\ | |||
c_3 s_1 + c_1 c_2 s_3 & c_3 c_1 - c_2 s_3 s_1 & s_2 s_3 \\ | |||
-c_1 s_2 & s_1 s_2 & c_2 | |||
\end{bmatrix}</math> | |||
!zyx | |||
|<math>\begin{bmatrix} | |||
c_2 c_1 & -c_2 s_1 & s_2 \\ | |||
s_3 s_2 c_1+c_3 s_1 & -s_3 s_2 s_1+c_3 c_1 & -s_3 c_2 \\ | |||
-c_3 s_2 c_1+s_3 s_1 & c_3 s_2 s_1+s_3 c_1 & c_3 c_2 | |||
\end{bmatrix}</math> | |||
|- | |||
!zxz | |||
|<math>\begin{bmatrix} | |||
c_3 c_1 - c_2 s_1 s_3 & - c_3 s_1 - c_1 c_2 s_3 & s_2 s_3 \\ | |||
c_2 c_3 s_1 + c_1 s_3 & c_3 c_2 c_1 - s_3 s_1 & - c_3 s_2 \\ | |||
s_1 s_2 & c_1 s_2 & c_2 | |||
\end{bmatrix}</math> | |||
!zxy | |||
|<math>\begin{bmatrix} | |||
c_3 c_1+s_3 s_2 s_1 & -c_3 s_1+s_3 s_2 c_1 & s_3 c_2 \\ | |||
c_2 s_1 & c_2 c_1 & -s_2 \\ | |||
-s_3 c_1+c_3 s_2 s_1 & s_3 s_1+c_3 s_2 c_1 & c_3 c_2 | |||
\end{bmatrix}</math> | |||
|} | |||
== See also == | |||
* [[Jacobi rotation]] | |||
* [[Plane of rotation]] | |||
* [[Householder transformation]] | |||
== Notes == | |||
<references/> | |||
== References == | |||
* {{Citation | last1=Anderson | first1=Edward | url=http://www.netlib.org/lapack/lawns/downloads/ | title=Discontinuous Plane Rotations and the Symmetric Eigenvalue Problem | year=2000 }}. LAPACK Working Note 150, University of Tennessee, UT-CS-00-454, December 4, 2000. | |||
* D. Bindel, J. Demmel, W. Kahan, O. Marques. (2001) ''[http://www.netlib.org/lapack/lawns/downloads/ On Computing Givens rotations reliably and efficiently]''. LAPACK Working Note 148, University of Tennessee, UT-CS-00-449, January 31, 2001.<!-- The paper itself says January 2001, but the LAWN site says October 2000. --> | |||
* {{Citation | |||
| last = Cybenko | |||
| first = George | |||
| title = Reducing Quantum Computations to Elementary Unitary Operations | |||
| journal = Computing in Science and Engineering | |||
| volume = 3 | |||
| issue = 2 | |||
| pages = 27–32 | |||
| date = March–April 2001 | |||
| doi = 10.1109/5992.908999 | |||
| url = http://vlsicad.eecs.umich.edu/Quantum/papers/QC-Unitary.pdf | |||
}} | |||
* {{Citation | last1=Golub | first1=Gene H. | author1-link=Gene H. Golub | last2=Van Loan | first2=Charles F. | author2-link=Charles F. Van Loan | title=Matrix Computations | publisher=Johns Hopkins | edition=3rd | isbn=978-0-8018-5414-9 | year=1996}}. | |||
*{{Citation | last1=Press | first1=WH | last2=Teukolsky | first2=SA | last3=Vetterling | first3=WT | last4=Flannery | first4=BP | year=2007 | title=Numerical Recipes: The Art of Scientific Computing | edition=3rd | publisher=Cambridge University Press | publication-place=New York | isbn=978-0-521-88068-8 | chapter=Section 11.3.1. Givens Method | chapter-url=http://apps.nrbook.com/empanel/index.html#pg=578}} | |||
{{Numerical linear algebra}} | |||
[[Category:Numerical linear algebra]] | |||
[[Category:Matrices]] |
Revision as of 02:10, 30 January 2014
In numerical linear algebra, a Givens rotation is a rotation in the plane spanned by two coordinates axes. Givens rotations are named after Wallace Givens, who introduced them to numerical analysts in the 1950s while he was working at Argonne National Laboratory.
Matrix representation
A Givens rotation is represented by a matrix of the form
where c = cos(θ) and s = sin(θ) appear at the intersections ith and jth rows and columns. That is, the non-zero elements of Givens matrix is given by:
The product G(i,j,θ)x represents a counterclockwise rotation of the vector x in the (i,j) plane of θ radians, hence the name Givens rotation.
The main use of Givens rotations in numerical linear algebra is to introduce zeros in vectors or matrices. This effect can, for example, be employed for computing the QR decomposition of a matrix. One advantage over Householder transformations is that they can easily be parallelised, and another is that often for very sparse matrices they have a lower operation count.
Stable calculation
When a Givens rotation matrix, G(i,j,θ), multiplies another matrix, A, from the left, GA, only rows i and j of A are affected. Thus we restrict attention to the following problem. Given a and b, find c = cos θ and s = sin θ such that
Explicit calculation of θ is rarely necessary or desirable. Instead we directly seek c, s, and r. An obvious solution would be
However, the computation for r may overflow or underflow. An alternative formulation avoiding this problem Template:Harv is implemented as the hypot function in many programming languages .
Furthermore, as Template:Harvtxt discovered in improving LAPACK, a previously overlooked numerical consideration is continuity. To achieve this, we require r to be positive.
if (b = 0) then {c ← copysign(1,a); s ← 0; r ← abs(a)} else if (a = 0) then {c ← 0; s ← -copysign(1,b); r ← abs(b)} else if (abs(b) > abs(a)) then t ← a/b u ← copysign(sqrt(1+t*t),b) s ← -1/u c ← -s*t r ← b*u else t ← b/a u ← copysign(sqrt(1+t*t),a) c ← 1/u s ← -c*t r ← a*u
This is written in terms of the IEEE 754 copysign(x,y) function, which provides a safe and cheap way to copy the sign of y to x. If that is not available, |x|*sgn(y), using the sign function, is an alternative.
Triangularization
Given the following 3x3 Matrix, perform two iterations of the Given's Rotation to bring the matrix to an upper Triangular matrix in order to compute the QR decomposition.
In order to form the desired matrix, we must zero elements (2,1) and (3,2). We first select element (2,1) to zero. Using a rotation matrix of:
We have the following matrix multiplication:
Where:
Plugging in these values for c and s and performing the matrix multiplication above yields a new A of:
We now want to zero element (3,2) to finish off the process. Using the same idea as before, we have a rotation matrix of:
We are presented with the following matrix multiplication:
Where:
Plugging in these values for c and s and performing the multiplications gives us a new matrix of:
This new matrix R is the upper triangular matrix needed to perform an iteration of the QR decomposition. Q is now formed using the transpose of the rotation matrices in the following manner:
Performing this matrix multiplication yields:
This completes two iterations of the Givens Rotation and calculating the QR decomposition can now be done.
Givens rotations in Clifford Algebras
In Clifford algebras and its child structures like geometric algebra rotations are represented by bivectors. Givens rotations are represented by the external product of the basis vectors. Given any pair of basis vectors Givens rotations bivectors are:
Their action on any vector is written :
where :
Dimension 3
- See also Euler angles
There are three Givens rotations in dimension 3:
Note: The matrix immediately below is __not__ a Givens rotation. The matrix immediately below respects the right-hand rule ... and is this usual matrix one sees in Computer Graphics; however, a Givens rotation is simply a matrix as defined in the Matrix representation section above and does not necessarily respect the right-hand rule. This section should be considered suspect.
Note: The actual Givens rotation matrix for would be:
Given that they are endomorphisms they can be composed with each other as many times as desired, keeping in mind that g ∘ f ≠ f ∘ g.
These three Givens rotations composed can generate any rotation matrix. This means that they can transform the basis of the space to any other frame in the space.
When rotations are performed in the right order, the values of the rotation angles of the final frame will be equal to the Euler angles of the final frame in the corresponding convention. For example, an operator transforms the basis of the space into a frame with angles roll, pitch and yaw in the Tait-Bryan convention z-x-y (convention in which the line of nodes is perpendicular to z and Y axes, also named Y-X’-Z’’).
For the same reason, any rotation matrix in 3D can be decomposed in a product of three of these rotations.
The meaning of the composition of two Givens rotations g∘f is an operator that transforms vectors first by f and then by g, being f and g rotations about one axis of basis of the space. This is similar to the extrinsic rotation equivalence for Euler angles.
Table of composed rotations
The following table shows the three Givens rotations equivalent to the different Euler angles conventions using extrinsic composition (composition of rotations about the basis axes) of active rotations and the right-handed rule for the positive sign of the angles.
The notation has been simplified in such a way that c1 means cos(θ1) and s2 means sin(θ2). The subindexes of the angles are the order in which they are applied using extrinsic composition (1 for intrinsic rotation, 2 for nutation, 3 for precession)
As rotations are applied just in the opposite order of the Euler angles table of rotations, this table is the same but swapping indexes 1 and 3 in the angles associated with the corresponding entry. An entry like zxy means to apply first the y rotation, then x, and finally z, in the basis axes.
All the compositions assume the right hand convention for the matrices that are multiplied, yielding the following results[1]
See also
Notes
References
- Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.
Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.
In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.
Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region
Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.
15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.
To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010. LAPACK Working Note 150, University of Tennessee, UT-CS-00-454, December 4, 2000. - D. Bindel, J. Demmel, W. Kahan, O. Marques. (2001) On Computing Givens rotations reliably and efficiently. LAPACK Working Note 148, University of Tennessee, UT-CS-00-449, January 31, 2001.
- Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.
Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.
In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.
Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region
Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.
15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.
To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010 - Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.
Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.
In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.
Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region
Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.
15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.
To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010. - Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.
Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.
In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.
Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region
Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.
15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.
To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010