org.apache.mahout.math
Class SingularValueDecomposition

java.lang.Object
  extended by org.apache.mahout.math.SingularValueDecomposition
All Implemented Interfaces:
Serializable

public class SingularValueDecomposition
extends Object
implements Serializable

See Also:
Serialized Form

Constructor Summary
SingularValueDecomposition(Matrix arg)
          Constructs and returns a new singular value decomposition object; The decomposed matrices can be retrieved via instance methods of the returned decomposition object.
 
Method Summary
 double cond()
          Returns the two norm condition number, which is max(S) / min(S).
 Matrix getS()
           
 double[] getSingularValues()
          Returns the diagonal of S, which is a one-dimensional array of singular values
 Matrix getU()
          Returns the left singular vectors U.
 Matrix getV()
          Returns the right singular vectors V.
 double norm2()
          Returns the two norm, which is max(S).
 int rank()
          Returns the effective numerical matrix rank, which is the number of nonnegligible singular values.
 String toString()
          Returns a String with (propertyName, propertyValue) pairs.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

SingularValueDecomposition

public SingularValueDecomposition(Matrix arg)
Constructs and returns a new singular value decomposition object; The decomposed matrices can be retrieved via instance methods of the returned decomposition object.

Parameters:
arg - A rectangular matrix.
Method Detail

cond

public double cond()
Returns the two norm condition number, which is max(S) / min(S).


getS

public Matrix getS()
Returns:
the diagonal matrix of singular values.

getSingularValues

public double[] getSingularValues()
Returns the diagonal of S, which is a one-dimensional array of singular values

Returns:
diagonal of S.

getU

public Matrix getU()
Returns the left singular vectors U.

Returns:
U

getV

public Matrix getV()
Returns the right singular vectors V.

Returns:
V

norm2

public double norm2()
Returns the two norm, which is max(S).


rank

public int rank()
Returns the effective numerical matrix rank, which is the number of nonnegligible singular values.


toString

public String toString()
Returns a String with (propertyName, propertyValue) pairs. Useful for debugging or to quickly get the rough picture. For example,
 rank          : 3
 trace         : 0
 

Overrides:
toString in class Object


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