dlarrr.f(3) LAPACK dlarrr.f(3)NAMEdlarrr.f-
SYNOPSIS
Functions/Subroutines
subroutine dlarrr (N, D, E, INFO)
DLARRR performs tests to decide whether the symmetric tridiagonal
matrix T warrants expensive computations which guarantee high
relative accuracy in the eigenvalues.
Function/Subroutine Documentation
subroutine dlarrr (integerN, double precision, dimension( * )D, double
precision, dimension( * )E, integerINFO)
DLARRR performs tests to decide whether the symmetric tridiagonal
matrix T warrants expensive computations which guarantee high relative
accuracy in the eigenvalues.
Purpose:
Perform tests to decide whether the symmetric tridiagonal matrix T
warrants expensive computations which guarantee high relative accuracy
in the eigenvalues.
Parameters:
N
N is INTEGER
The order of the matrix. N > 0.
D
D is DOUBLE PRECISION array, dimension (N)
The N diagonal elements of the tridiagonal matrix T.
E
E is DOUBLE PRECISION 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.
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 dlarrr.f.
Author
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Version 3.4.2 Sat Nov 16 2013 dlarrr.f(3)