Package org.ejml.dense.row.decomposition.eig.symm

Class SymmetricQREigenHelper_DDRM

java.lang.Object
org.ejml.dense.row.decomposition.eig.symm.SymmetricQREigenHelper_DDRM
public class SymmetricQREigenHelper_DDRM extends Object
A helper class for the symmetric matrix implicit QR algorithm for eigenvalue decomposition. Performs most of the basic operations needed to extract eigenvalues and eigenvectors.

  • Field Details

    • rand

      protected Random rand

    • steps

      protected int steps

    • numExceptional

      protected int numExceptional

    • lastExceptional

      protected int lastExceptional

    • eigenSmall

      protected EigenvalueSmall_F64 eigenSmall

    • Q

      @Nullable protected @Nullable DMatrixRMaj Q

    • N

      protected int N

    • diag

      protected double[] diag

    • off

      protected double[] off

    • x1

      protected int x1

    • x2

      protected int x2

    • splits

      protected int[] splits

    • numSplits

      protected int numSplits

  • Constructor Details

    • SymmetricQREigenHelper_DDRM

      public SymmetricQREigenHelper_DDRM()

  • Method Details

    • printMatrix

      public void printMatrix()

    • setQ

      public void setQ(DMatrixRMaj q)

    • incrementSteps

      public void incrementSteps()

    • init

      public void init(double[] diag, double[] off, int numCols)
      Sets up and declares internal data structures.
      Parameters:
      diag - Diagonal elements from tridiagonal matrix. Modified.
      off - Off diagonal elements from tridiagonal matrix. Modified.
      numCols - number of columns (and rows) in the matrix.

    • swapDiag

      public double[] swapDiag(double[] diag)
      Exchanges the internal array of the diagonal elements for the provided one.

    • swapOff

      public double[] swapOff(double[] off)
      Exchanges the internal array of the off diagonal elements for the provided one.

    • reset

      public void reset(int N)
      Sets the size of the matrix being decomposed, declares new memory if needed, and sets all helper functions to their initial value.

    • copyDiag

      public double[] copyDiag(double[] ret)

    • copyOff

      public double[] copyOff(double[] ret)

    • copyEigenvalues

      public double[] copyEigenvalues(double[] ret)

    • setSubmatrix

      public void setSubmatrix(int x1, int x2)
      Sets which submatrix is being processed.
      Parameters:
      x1 - Lower bound, inclusive.
      x2 - Upper bound, inclusive.

    • isZero

      protected boolean isZero(int index)
      Checks to see if the specified off diagonal element is zero using a relative metric.

    • performImplicitSingleStep

      protected void performImplicitSingleStep(double lambda, boolean byAngle)

    • updateQ

      protected void updateQ(int m, int n, double c, double s)

    • createBulge

      protected void createBulge(int x1, double p, boolean byAngle)
      Performs a similar transform on A-pI

    • createBulge2by2

      protected void createBulge2by2(int x1, double p, boolean byAngle)

    • removeBulge

      protected void removeBulge(int x1)

    • removeBulgeEnd

      protected void removeBulgeEnd(int x1)
      Rotator to remove the bulge

    • eigenvalue2by2

      protected void eigenvalue2by2(int x1)
      Computes the eigenvalue of the 2 by 2 matrix.

    • exceptionalShift

      public void exceptionalShift()
      Perform a shift in a random direction that is of the same magnitude as the elements in the matrix.

    • nextSplit

      public boolean nextSplit()
      Tells it to process the submatrix at the next split. Should be called after the current submatrix has been processed.

    • computeShift

      public double computeShift()

    • computeWilkinsonShift

      public double computeWilkinsonShift()

    • getMatrixSize

      public int getMatrixSize()

    • resetSteps

      public void resetSteps()