slaed5 (l)  Linux Man Pages
slaed5: subroutine compute the Ith eigenvalue of a symmetric rankone modification of a 2by2 diagonal matrix diag( D ) + RHO The diagonal elements in the array D are assumed to satisfy D(i) < D(j) for i < j
Command to display slaed5
manual in Linux: $ man l slaed5
NAME
SLAED5  subroutine compute the Ith eigenvalue of a symmetric rankone modification of a 2by2 diagonal matrix diag( D ) + RHO The diagonal elements in the array D are assumed to satisfy D(i) < D(j) for i < j
SYNOPSIS
 SUBROUTINE SLAED5(

I, D, Z, DELTA, RHO, DLAM )

INTEGER
I

REAL
DLAM, RHO

REAL
D( 2 ), DELTA( 2 ), Z( 2 )
PURPOSE
This subroutine computes the Ith eigenvalue of a symmetric rankone
modification of a 2by2 diagonal matrix
We also assume RHO > 0 and that the Euclidean norm of the vector
Z is one.
ARGUMENTS
 I (input) INTEGER

The index of the eigenvalue to be computed. I = 1 or I = 2.
 D (input) REAL array, dimension (2)

The original eigenvalues. We assume D(1) < D(2).
 Z (input) REAL array, dimension (2)

The components of the updating vector.
 DELTA (output) REAL array, dimension (2)

The vector DELTA contains the information necessary
to construct the eigenvectors.
 RHO (input) REAL

The scalar in the symmetric updating formula.
 DLAM (output) REAL

The computed lambda_I, the Ith updated eigenvalue.
FURTHER DETAILS
Based on contributions by
RenCang Li, Computer Science Division, University of California
at Berkeley, USA
Pages related to slaed5
 slaed5 (3)
 slaed0 (l)  computes all eigenvalues and corresponding eigenvectors of a symmetric tridiagonal matrix using the divide and conquer method
 slaed1 (l)  computes the updated eigensystem of a diagonal matrix after modification by a rankone symmetric matrix
 slaed2 (l)  merges the two sets of eigenvalues together into a single sorted set
 slaed3 (l)  finds the roots of the secular equation, as defined by the values in D, W, and RHO, between 1 and K
 slaed4 (l)  subroutine compute the Ith updated eigenvalue of a symmetric rankone modification to a diagonal matrix whose elements are given in the array d, and that D(i) < D(j) for i < j and that RHO > 0
 slaed6 (l)  computes the positive or negative root (closest to the origin) of z(1) z(2) z(3) f(x) = rho +  +  +  d(1)x d(2)x d(3)x It is assumed that if ORGATI = .true
 slaed7 (l)  computes the updated eigensystem of a diagonal matrix after modification by a rankone symmetric matrix
 slaed8 (l)  merges the two sets of eigenvalues together into a single sorted set
 slaed9 (l)  finds the roots of the secular equation, as defined by the values in D, Z, and RHO, between KSTART and KSTOP
 slaeda (l)  computes the Z vector corresponding to the merge step in the CURLVLth step of the merge process with TLVLS steps for the CURPBMth problem