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dlarrr.f(3) LAPACK dlarrr.f(3)

NAME

dlarrr.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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