SLAED9 (3)  Linux Manuals
NAME
slaed9.f 
SYNOPSIS
Functions/Subroutines
subroutine slaed9 (K, KSTART, KSTOP, N, D, Q, LDQ, RHO, DLAMDA, W, S, LDS, INFO)
SLAED9 used by sstedc. Finds the roots of the secular equation and updates the eigenvectors. Used when the original matrix is dense.
Function/Subroutine Documentation
subroutine slaed9 (integerK, integerKSTART, integerKSTOP, integerN, real, dimension( * )D, real, dimension( ldq, * )Q, integerLDQ, realRHO, real, dimension( * )DLAMDA, real, dimension( * )W, real, dimension( lds, * )S, integerLDS, integerINFO)
SLAED9 used by sstedc. Finds the roots of the secular equation and updates the eigenvectors. Used when the original matrix is dense.
Purpose:

SLAED9 finds the roots of the secular equation, as defined by the values in D, Z, and RHO, between KSTART and KSTOP. It makes the appropriate calls to SLAED4 and then stores the new matrix of eigenvectors for use in calculating the next level of Z vectors.
Parameters:

K
K is INTEGER The number of terms in the rational function to be solved by SLAED4. K >= 0.
KSTARTKSTART is INTEGER
KSTOPKSTOP is INTEGER The updated eigenvalues Lambda(I), KSTART <= I <= KSTOP are to be computed. 1 <= KSTART <= KSTOP <= K.
NN is INTEGER The number of rows and columns in the Q matrix. N >= K (delation may result in N > K).
DD is REAL array, dimension (N) D(I) contains the updated eigenvalues for KSTART <= I <= KSTOP.
QQ is REAL array, dimension (LDQ,N)
LDQLDQ is INTEGER The leading dimension of the array Q. LDQ >= max( 1, N ).
RHORHO is REAL The value of the parameter in the rank one update equation. RHO >= 0 required.
DLAMDADLAMDA is REAL array, dimension (K) The first K elements of this array contain the old roots of the deflated updating problem. These are the poles of the secular equation.
WW is REAL array, dimension (K) The first K elements of this array contain the components of the deflationadjusted updating vector.
SS is REAL array, dimension (LDS, K) Will contain the eigenvectors of the repaired matrix which will be stored for subsequent Z vector calculation and multiplied by the previously accumulated eigenvectors to update the system.
LDSLDS is INTEGER The leading dimension of S. LDS >= max( 1, K ).
INFOINFO is INTEGER = 0: successful exit. < 0: if INFO = i, the ith argument had an illegal value. > 0: if INFO = 1, an eigenvalue did not converge
Author:

Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
 September 2012
Contributors:
 Jeff Rutter, Computer Science Division, University of California at Berkeley, USA
Definition at line 156 of file slaed9.f.
Author
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