weka.core.matrix

## Class SingularValueDecomposition

- java.lang.Object
- - weka.core.matrix.SingularValueDecomposition

- All Implemented Interfaces:
    java.io.Serializable, RevisionHandler

      public class SingularValueDecomposition
      extends java.lang.Object
      implements java.io.Serializable, RevisionHandler

  Singular Value Decomposition.

  For an m-by-n matrix A with m >= n, the singular value decomposition is an m-by-n orthogonal matrix U, an n-by-n diagonal matrix S, and an n-by-n orthogonal matrix V so that A = U*S*V'.

  The singular values, sigma[k] = S[k][k], are ordered so that sigma[0] >= sigma[1] >= ... >= sigma[n-1].

  The singular value decompostion always exists, so the constructor will never fail. The matrix condition number and the effective numerical rank can be computed from this decomposition.

  Adapted from the JAMA package.
  Version:
    $Revision: 5953 $
  Author:
    The Mathworks and NIST, Fracpete (fracpete at waikato dot ac dot nz)
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `SingularValueDecomposition(Matrix Arg)` Construct the singular value decomposition

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `double` | `cond()` Two norm condition number
    `java.lang.String` | `getRevision()` Returns the revision string.
    `Matrix` | `getS()` Return the diagonal matrix of singular values
    `double[]` | `getSingularValues()` Return the one-dimensional array of singular values
    `Matrix` | `getU()` Return the left singular vectors
    `Matrix` | `getV()` Return the right singular vectors
    `double` | `norm2()` Two norm
    `int` | `rank()` Effective numerical matrix rank

    - ### Methods inherited from class java.lang.Object

      `equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### SingularValueDecomposition

          public SingularValueDecomposition(Matrix Arg)

      Construct the singular value decomposition
      Parameters:
        `Arg` - Rectangular matrix

  - ### Method Detail

    - #### getU

          public Matrix getU()

      Return the left singular vectors
      Returns:
        U

    - #### getV

          public Matrix getV()

      Return the right singular vectors
      Returns:
        V

    - #### getSingularValues

          public double[] getSingularValues()

      Return the one-dimensional array of singular values
      Returns:
        diagonal of S.

    - #### getS

          public Matrix getS()

      Return the diagonal matrix of singular values
      Returns:
        S

    - #### norm2

          public double norm2()

      Two norm
      Returns:
        max(S)

    - #### cond

          public double cond()

      Two norm condition number
      Returns:
        max(S)/min(S)

    - #### rank

          public int rank()

      Effective numerical matrix rank
      Returns:
        Number of nonnegligible singular values.

    - #### getRevision

          public java.lang.String getRevision()

      Returns the revision string.
      Specified by:
        `getRevision` in interface `RevisionHandler`
      Returns:
        the revision