Class Getvec
- java.lang.Object
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- dev.nm.algebra.linear.matrix.doubles.factorization.eigen.mr3.getvec.Getvec
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public class Getvec extends Object
Computes the (scaled) r-th column of the inverse of the sub-matrix block of the tridiagonal matrix T = LDLT - λ I. This is essentially Algorithm Getvec. This is used to compute an Fernando and Parlett (FP) vector of a singleton in MRRR.- See Also:
- "Dhillon, Inderjit S. and Parlett, Beresford N., "Multiple representations to compute orthogonal eigenvectors of symmetric tridiagonal matrices", Linear Algebra and its Applications, 2004, 387, pp. 1-28."
- "Dhillon, Inderjit S. and Parlett, Beresford N., "Orthogonal eigenvectors and relative gaps", SIAM Journal on Matrix Analysis and Applications, 2004, Vol. 25, pp. 858-899."
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Constructor Summary
Constructors Constructor Description Getvec(LDDecomposition LDLt, double lambda, int twistIndex, double gapTolerance, double minPivot)
Computes an FP vector of a singleton.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Vector
getEigenvector()
int
getFirstNonZeroIndex()
double
getInverseNorm()
int
getLastNonZeroIndex()
int
getNegCount()
double
getResidual()
double
getRQCorrection()
int
getTwistIndex()
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Constructor Detail
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Getvec
public Getvec(LDDecomposition LDLt, double lambda, int twistIndex, double gapTolerance, double minPivot)
Computes an FP vector of a singleton.- Parameters:
LDLt
- the robust representation LDLTlambda
- the shift λtwistIndex
- the twist index rgapTolerance
- the gap toleranceminPivot
- the minimum pivot in the Sturm sequence for T
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Method Detail
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getNegCount
public int getNegCount()
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getTwistIndex
public int getTwistIndex()
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getInverseNorm
public double getInverseNorm()
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getResidual
public double getResidual()
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getRQCorrection
public double getRQCorrection()
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getFirstNonZeroIndex
public int getFirstNonZeroIndex()
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getLastNonZeroIndex
public int getLastNonZeroIndex()
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getEigenvector
public Vector getEigenvector()
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