slarrr()

subroutine slarrr	(	integer	n,
		real, dimension( * )	d,
		real, dimension( * )	e,
		integer	info )

SLARRR performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues.

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Purpose:

!>
!> Perform tests to decide whether the symmetric tridiagonal matrix T
!> warrants expensive computations which guarantee high relative accuracy
!> in the eigenvalues.
!> 

Parameters

[in]	N	!> N is INTEGER !> The order of the matrix. N > 0. !>
[in]	D	!> D is REAL array, dimension (N) !> The N diagonal elements of the tridiagonal matrix T. !>
[in,out]	E	!> E is REAL array, dimension (N) !> On entry, the first (N-1) entries contain the subdiagonal !> elements of the tridiagonal matrix T; E(N) is set to ZERO. !>
[out]	INFO	!> INFO is INTEGER !> INFO = 0(default) : the matrix warrants computations preserving !> relative accuracy. !> INFO = 1 : the matrix warrants computations guaranteeing !> only absolute accuracy. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Contributors:

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