org.encog.mathutil.matrices.decomposition
Class SingularValueDecomposition
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- org.encog.mathutil.matrices.decomposition.SingularValueDecomposition
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public class SingularValueDecomposition extends java.lang.ObjectSingular 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. This file based on a class from the public domain JAMA package. http://math.nist.gov/javanumerics/jama/
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Constructor Summary
Constructors Constructor and Description SingularValueDecomposition(Matrix Arg)Construct the singular value decomposition Structure to access U, S and V.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description doublecond()Two norm condition numberMatrixgetS()Return the diagonal matrix of singular valuesdouble[]getSingularValues()Return the one-dimensional array of singular valuesMatrixgetU()Return the left singular vectorsMatrixgetV()Return the right singular vectorsdoublenorm2()Two normintrank()Effective numerical matrix rank
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Constructor Detail
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SingularValueDecomposition
public SingularValueDecomposition(Matrix Arg)
Construct the singular value decomposition Structure to access U, S and V.- Parameters:
Arg- Rectangular matrix
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Method Detail
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getU
public Matrix getU()
Return the left singular vectors- Returns:
- U
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getV
public Matrix getV()
Return the right singular vectors- Returns:
- V
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getSingularValues
public double[] getSingularValues()
Return the one-dimensional array of singular values- Returns:
- diagonal of S.
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getS
public Matrix getS()
Return the diagonal matrix of singular values- Returns:
- S
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norm2
public double norm2()
Two norm- Returns:
- max(S)
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cond
public double cond()
Two norm condition number- Returns:
- max(S)/min(S)
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rank
public int rank()
Effective numerical matrix rank- Returns:
- Number of nonnegligible singular values.
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