Package org.carrot2.math.matrix

Class NonnegativeMatrixFactorizationKL

java.lang.Object
org.carrot2.math.matrix.NonnegativeMatrixFactorizationKL
All Implemented Interfaces:
IterativeMatrixFactorization, MatrixFactorization
public class NonnegativeMatrixFactorizationKL
extends Object
Performs matrix factorization using the Non-negative Matrix Factorization by minimization of Kullback-Leibler divergence between A and UV' and multiplicative updating.

  • Field Details

    • k

      protected int k
      The desired number of base vectors

    • DEFAULT_K

      protected static int DEFAULT_K

    • maxIterations

      protected int maxIterations
      The maximum number of iterations the algorithm is allowed to run

    • DEFAULT_MAX_ITERATIONS

      protected static final int DEFAULT_MAX_ITERATIONS
      See Also:
      Constant Field Values

    • stopThreshold

      protected double stopThreshold
      If the percentage decrease in approximation error becomes smaller than stopThreshold , the algorithm will stop. Note: calculation of approximation error is quite costly. Setting the threshold to -1 turns off approximation error calculation and hence makes the algorithm do the maximum number of iterations.

    • DEFAULT_STOP_THRESHOLD

      protected static double DEFAULT_STOP_THRESHOLD

    • seedingStrategy

      protected SeedingStrategy seedingStrategy
      Seeding strategy

    • DEFAULT_SEEDING_STRATEGY

      protected static final SeedingStrategy DEFAULT_SEEDING_STRATEGY

    • ordered

      protected boolean ordered
      Order base vectors according to their 'activity'?

    • DEFAULT_ORDERED

      protected static final boolean DEFAULT_ORDERED
      See Also:
      Constant Field Values

    • approximationError

      protected double approximationError
      Current approximation error

    • approximationErrors

      protected double[] approximationErrors
      Approximation errors during subsequent iterations

    • iterationsCompleted

      protected int iterationsCompleted
      Iteration counter

    • aggregates

      protected double[] aggregates
      Sorting aggregates

    • A

      protected org.carrot2.math.mahout.matrix.DoubleMatrix2D A
      Input matrix

    • U

      protected org.carrot2.math.mahout.matrix.DoubleMatrix2D U
      Base vector result matrix

    • V

      protected org.carrot2.math.mahout.matrix.DoubleMatrix2D V
      Coefficient result matrix

  • Constructor Details

    • NonnegativeMatrixFactorizationKL

      public NonnegativeMatrixFactorizationKL​(org.carrot2.math.mahout.matrix.DoubleMatrix2D A)
      Creates the NonnegativeMatrixFactorizationKL object for matrix A. Before accessing results, perform computations by calling the compute() method.
      Parameters:
      A - matrix to be factorized

  • Method Details

    • compute

      public void compute()
      Computes the factorization.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • setK

      public void setK​(int k)
      Sets the number of base vectors k .
      Parameters:
      k - the number of base vectors

    • getK

      public int getK()
      Returns the number of base vectors k .

    • updateApproximationError

      protected boolean updateApproximationError()
      Returns:
      true if the decrease in the approximation error is smaller than the stopThreshold

    • order

      protected void order()
      Orders U and V matrices according to the 'activity' of base vectors.

    • getSeedingStrategy

      public SeedingStrategy getSeedingStrategy()
      Returns current SeedingStrategy.

    • setSeedingStrategy

      public void setSeedingStrategy​(SeedingStrategy seedingStrategy)
      Sets new SeedingStrategy.

    • getMaxIterations

      public int getMaxIterations()
      Returns the maximum number of iterations the algorithm is allowed to run.

    • setMaxIterations

      public void setMaxIterations​(int maxIterations)
      Sets the maximum number of iterations the algorithm is allowed to run.

    • getStopThreshold

      public double getStopThreshold()
      Returns the algorithms stopThreshold. If the percentage decrease in approximation error becomes smaller than stopThreshold, the algorithm will stop.

    • setStopThreshold

      public void setStopThreshold​(double stopThreshold)
      Sets the algorithms stopThreshold. If the percentage decrease in approximation error becomes smaller than stopThreshold, the algorithm will stop.

      Note: calculation of approximation error is quite costly. Setting the threshold to -1 turns off calculation of the approximation error and hence makes the algorithm do the maximum allowed number of iterations.

    • getApproximationError

      public double getApproximationError()
      Description copied from interface: IterativeMatrixFactorization
      Returns approximation error achieved after the last iteration of the algorithm or -1 if the approximation error is not available.
      Specified by:
      getApproximationError in interface IterativeMatrixFactorization
      Returns:
      approximation error or -1

    • getApproximationErrors

      public double[] getApproximationErrors()

    • getIterationsCompleted

      public int getIterationsCompleted()
      Description copied from interface: IterativeMatrixFactorization
      Returns the number of iterations the algorithm has completed.
      Specified by:
      getIterationsCompleted in interface IterativeMatrixFactorization
      Returns:
      the number of iterations the algorithm has completed

    • isOrdered

      public boolean isOrdered()
      Returns true when the factorization is set to generate an ordered basis.

    • setOrdered

      public void setOrdered​(boolean ordered)
      Set to true to generate an ordered basis.

    • getAggregates

      public double[] getAggregates()
      Returns column aggregates for a sorted factorization, and null for an unsorted factorization.

    • getU

      public org.carrot2.math.mahout.matrix.DoubleMatrix2D getU()
      Description copied from interface: MatrixFactorization
      Returns the U matrix (base vectors matrix).
      Specified by:
      getU in interface MatrixFactorization
      Returns:
      U matrix

    • getV

      public org.carrot2.math.mahout.matrix.DoubleMatrix2D getV()
      Description copied from interface: MatrixFactorization
      Returns the V matrix (coefficient matrix)
      Specified by:
      getV in interface MatrixFactorization
      Returns:
      V matrix