slarrr (l)  Linux Man Pages
slarrr: tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues
Command to display slarrr
manual in Linux: $ man l slarrr
NAME
SLARRR  tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues
SYNOPSIS
 SUBROUTINE SLARRR(

N, D, E, INFO )

INTEGER
N, INFO

REAL
D( * ), E( * )
PURPOSE
Perform tests to decide whether the symmetric tridiagonal matrix T
warrants expensive computations which guarantee high relative accuracy
in the eigenvalues.
ARGUMENTS
 N (input) INTEGER

The order of the matrix. N > 0.
 D (input) REAL array, dimension (N)

The N diagonal elements of the tridiagonal matrix T.
 E (input/output) REAL array, dimension (N)

On entry, the first (N1) entries contain the subdiagonal
elements of the tridiagonal matrix T; E(N) is set to ZERO.
 INFO (output) INTEGER

INFO = 0(default) : the matrix warrants computations preserving
relative accuracy.
INFO = 1 : the matrix warrants computations guaranteeing
only absolute accuracy.
FURTHER DETAILS
Based on contributions by
Beresford Parlett, University of California, Berkeley, USA
Jim Demmel, University of California, Berkeley, USA
Inderjit Dhillon, University of Texas, Austin, USA
Osni Marques, LBNL/NERSC, USA
Christof Voemel, University of California, Berkeley, USA
Pages related to slarrr
 slarrr (3)
 slarra (l)  the splitting points with threshold SPLTOL
 slarrb (l)  the relatively robust representation(RRR) L D L^T, SLARRB does "limited" bisection to refine the eigenvalues of L D L^T,
 slarrc (l)  the number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = aqTaq, and of L D L^T if JOBT = aqLaq
 slarrd (l)  computes the eigenvalues of a symmetric tridiagonal matrix T to suitable accuracy
 slarre (l)  find the desired eigenvalues of a given real symmetric tridiagonal matrix T, SLARRE sets any "small" offdiagonal elements to zero, and for each unreduced block T_i, it finds (a) a suitable shift at one end of the blockaqs spectrum,
 slarrf (l)  the initial representation L D L^T and its cluster of close eigenvalues (in a relative measure), W( CLSTRT ), W( CLSTRT+1 ), ..
 slarrj (l)  the initial eigenvalue approximations of T, SLARRJ does bisection to refine the eigenvalues of T,
 slarrk (l)  computes one eigenvalue of a symmetric tridiagonal matrix T to suitable accuracy
 slarrv (l)  computes the eigenvectors of the tridiagonal matrix T = L D L^T given L, D and APPROXIMATIONS to the eigenvalues of L D L^T
 slar1v (l)  computes the (scaled) rth column of the inverse of the sumbmatrix in rows B1 through BN of the tridiagonal matrix L D L^T  sigma I