slarrr.f File Reference

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Functions/Subroutines
subroutine	slarrr (N, D, E, INFO)
	SLARRR performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues. More...

Function/Subroutine Documentation

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.

Date

September 2012

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

Definition at line 95 of file slarrr.f.

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