The upper left shows the unit disc in blue together with the two canonical unit vectors. The upper right shows the action of M on the unit disc: it distorts the circle to an ellipse. The SVD decomposes M into three simple transformations: a rotation V*, a scaling Σ along the coordinate axes and a second rotation U.
The SVD reveals the lengths σ1 resp. σ2 of the semi-major axis resp. semi-minor axis of the ellispe; they are just the singular values which occur as diagonal elements of the scaling Σ. The rotation of the ellipse with respect to the coordinate axes is given by U.
In this particular case the decomposition is as follows:
Oben links sieht man den Einheitskreis in blau zusammen mit den Standard-Einheitsvektoren. Oben rechts sieht man das Bild des Einheitskreises unter M: der Kreis wird zu einer Ellipse verzogen. Die SVD zerlegt M in drei einfache Transformationen: eine Rotation V*, eine Dehnung Σ entlang der Koordinatenachsen und eine zweite Rotation U.
Die Zerlegung lässt direkt die Längen σ1 bzw. σ2 der großen bzw. kleinen Halbachse der Ellipse erkennen; die Werte stehen in der Hauptdiagonalen von Σ. Die Rotation der Ellipse in Bezug auf das Koordinatensystem wird durch U beschrieben.
In diesem speziellen Fall sieht die Singulärwertzerlegung aus wie folgt::
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue
You may select the license of your choice.
Captions
Illustration of the singular value decomposition UΣV* of a real 2×2 matrix M.
{{Information |Description={{en|1=Visualisation of a singular value decomposition. details will follow}} |Source={{own}} |Author=Georg-Johann |Date=2010-08-28 |Permission= |other_versions= }} Category:SVG mathematics
Singular Value Decomposition of the 2-dimensional Shearing
M = ( 1 1 )
( 0 1 )
The Image shows:
Upper Left:
The unit Disc with the two canonical unit Vectors
Upper Right:
Unit Disc et al. transformed with M and signular Values
sigma_1 and sigma_2 indicated
Lower Left:
The Action of V^* on the Unit disc. This is a just
Rotation.
Lower Right:
The Action of Sigma * V^* on the Unit disc. Sigma scales in
vertically and horizontally.
The this special Case the singularValues are Phi and 1/Phi where
Phi is the Golden Ratio. V^* is a (counter clockwise) Rotation by
an angle alpha where alpha satisfies tan(alpha) = -Phi.
U is a Rotation by beta with tan(beta) = Phi-1