version 1.6, 2010/08/13 21:03:51
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version 1.9, 2011/11/21 22:19:34
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*> \brief \b DLARRR |
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* |
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* =========== DOCUMENTATION =========== |
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* |
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* Online html documentation available at |
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* http://www.netlib.org/lapack/explore-html/ |
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* |
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*> \htmlonly |
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*> Download DLARRR + dependencies |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarrr.f"> |
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*> [TGZ]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarrr.f"> |
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*> [ZIP]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarrr.f"> |
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*> [TXT]</a> |
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*> \endhtmlonly |
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* |
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* Definition: |
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* =========== |
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* |
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* SUBROUTINE DLARRR( N, D, E, INFO ) |
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* |
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* .. Scalar Arguments .. |
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* INTEGER N, INFO |
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* .. |
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* .. Array Arguments .. |
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* DOUBLE PRECISION D( * ), E( * ) |
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* .. |
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* |
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* |
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* |
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*> \par Purpose: |
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* ============= |
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*> |
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*> \verbatim |
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*> |
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*> Perform tests to decide whether the symmetric tridiagonal matrix T |
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*> warrants expensive computations which guarantee high relative accuracy |
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*> in the eigenvalues. |
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*> \endverbatim |
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* |
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* Arguments: |
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* ========== |
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* |
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*> \param[in] N |
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*> \verbatim |
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*> N is INTEGER |
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*> The order of the matrix. N > 0. |
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*> \endverbatim |
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*> |
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*> \param[in] D |
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*> \verbatim |
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*> D is DOUBLE PRECISION array, dimension (N) |
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*> The N diagonal elements of the tridiagonal matrix T. |
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*> \endverbatim |
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*> |
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*> \param[in,out] E |
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*> \verbatim |
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*> E is DOUBLE PRECISION array, dimension (N) |
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*> On entry, the first (N-1) entries contain the subdiagonal |
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*> elements of the tridiagonal matrix T; E(N) is set to ZERO. |
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*> \endverbatim |
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*> |
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*> \param[out] INFO |
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*> \verbatim |
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*> INFO is INTEGER |
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*> INFO = 0(default) : the matrix warrants computations preserving |
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*> relative accuracy. |
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*> INFO = 1 : the matrix warrants computations guaranteeing |
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*> only absolute accuracy. |
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*> \endverbatim |
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* |
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* Authors: |
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* ======== |
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* |
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*> \author Univ. of Tennessee |
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*> \author Univ. of California Berkeley |
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*> \author Univ. of Colorado Denver |
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*> \author NAG Ltd. |
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* |
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*> \date November 2011 |
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* |
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*> \ingroup auxOTHERauxiliary |
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* |
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*> \par Contributors: |
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* ================== |
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*> |
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*> Beresford Parlett, University of California, Berkeley, USA \n |
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*> Jim Demmel, University of California, Berkeley, USA \n |
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*> Inderjit Dhillon, University of Texas, Austin, USA \n |
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*> Osni Marques, LBNL/NERSC, USA \n |
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*> Christof Voemel, University of California, Berkeley, USA |
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* |
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* ===================================================================== |
SUBROUTINE DLARRR( N, D, E, INFO ) |
SUBROUTINE DLARRR( N, D, E, INFO ) |
* |
* |
* -- LAPACK auxiliary routine (version 3.2) -- |
* -- LAPACK auxiliary routine (version 3.4.0) -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* November 2006 |
* November 2011 |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER N, INFO |
INTEGER N, INFO |
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* .. |
* .. |
* |
* |
* |
* |
* Purpose |
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* ======= |
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* |
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* Perform tests to decide whether the symmetric tridiagonal matrix T |
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* warrants expensive computations which guarantee high relative accuracy |
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* in the eigenvalues. |
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* |
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* Arguments |
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* ========= |
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* |
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* N (input) INTEGER |
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* The order of the matrix. N > 0. |
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* |
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* D (input) DOUBLE PRECISION array, dimension (N) |
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* The N diagonal elements of the tridiagonal matrix T. |
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* |
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* E (input/output) DOUBLE PRECISION array, dimension (N) |
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* On entry, the first (N-1) entries contain the subdiagonal |
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* elements of the tridiagonal matrix T; E(N) is set to ZERO. |
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* |
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* INFO (output) INTEGER |
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* INFO = 0(default) : the matrix warrants computations preserving |
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* relative accuracy. |
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* INFO = 1 : the matrix warrants computations guaranteeing |
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* only absolute accuracy. |
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* |
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* Further Details |
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* =============== |
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* |
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* Based on contributions by |
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* Beresford Parlett, University of California, Berkeley, USA |
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* Jim Demmel, University of California, Berkeley, USA |
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* Inderjit Dhillon, University of Texas, Austin, USA |
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* Osni Marques, LBNL/NERSC, USA |
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* Christof Voemel, University of California, Berkeley, USA |
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* |
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* ===================================================================== |
* ===================================================================== |
* |
* |
* .. Parameters .. |
* .. Parameters .. |