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DLASD5Run Method

Purpose ======= This subroutine computes the square root of the I-th eigenvalue of a positive symmetric rank-one modification of a 2-by-2 diagonal matrix diag( D ) * diag( D ) + RHO * Z * transpose(Z) . The diagonal entries in the array D are assumed to satisfy 0 .LE. D(i) .LT. D(j) for i .LT. j . We also assume RHO .GT. 0 and that the Euclidean norm of the vector Z is one.

Namespace: DotNumerics.LinearAlgebra.CSLapack
Assembly: DWSIM.MathOps.DotNumerics (in DWSIM.MathOps.DotNumerics.dll) Version: 1.0.0.0 (1.0.0.0)
Syntax
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public void Run(
	int I,
	double[] D,
	int offset_d,
	double[] Z,
	int offset_z,
	ref double[] DELTA,
	int offset_delta,
	double RHO,
	ref double DSIGMA,
	ref double[] WORK,
	int offset_work
)
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Parameters

I  Int32
(input) INTEGER The index of the eigenvalue to be computed. I = 1 or I = 2.
D  Double
(input) DOUBLE PRECISION array, dimension ( 2 ) The original eigenvalues. We assume 0 .LE. D(1) .LT. D(2).
offset_d  Int32
 
Z  Double
(input) DOUBLE PRECISION array, dimension ( 2 ) The components of the updating vector.
offset_z  Int32
 
DELTA  Double
(output) DOUBLE PRECISION array, dimension ( 2 ) Contains (D(j) - sigma_I) in its j-th component. The vector DELTA contains the information necessary to construct the eigenvectors.
offset_delta  Int32
 
RHO  Double
(input) DOUBLE PRECISION The scalar in the symmetric updating formula.
DSIGMA  Double
(output) DOUBLE PRECISION The computed sigma_I, the I-th updated eigenvalue.
WORK  Double
(workspace) DOUBLE PRECISION array, dimension ( 2 ) WORK contains (D(j) + sigma_I) in its j-th component.
offset_work  Int32
 
See Also