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larrr - Man Page

larrr: step in stemr, test to do expensive tridiag eig algorithm

Synopsis

Functions

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.
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.

Detailed Description

Function Documentation

subroutine dlarrr (integer n, double precision, dimension( * ) d, double precision, dimension( * ) e, integer info)

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.

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 93 of file dlarrr.f.

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.  

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

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.

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

Definition at line 93 of file slarrr.f.

Author

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Info

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK