[BACK]Return to dlaed6.f CVS log [TXT] [DIR] Up to [local] / rpl / lapack / lapack

Diff for /rpl/lapack/lapack/dlaed6.f between versions 1.8 and 1.9

version 1.8, 2011/07/22 07:40:26 version 1.9, 2011/11/21 20:42:54
Line 1 Line 1
   *> \brief \b DLAED6
   *
   *  =========== DOCUMENTATION ===========
   *
   * Online html documentation available at 
   *            http://www.netlib.org/lapack/explore-html/ 
   *
   *> \htmlonly
   *> Download DLAED6 + dependencies 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaed6.f"> 
   *> [TGZ]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaed6.f"> 
   *> [ZIP]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaed6.f"> 
   *> [TXT]</a>
   *> \endhtmlonly 
   *
   *  Definition:
   *  ===========
   *
   *       SUBROUTINE DLAED6( KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO )
   * 
   *       .. Scalar Arguments ..
   *       LOGICAL            ORGATI
   *       INTEGER            INFO, KNITER
   *       DOUBLE PRECISION   FINIT, RHO, TAU
   *       ..
   *       .. Array Arguments ..
   *       DOUBLE PRECISION   D( 3 ), Z( 3 )
   *       ..
   *  
   *
   *> \par Purpose:
   *  =============
   *>
   *> \verbatim
   *>
   *> DLAED6 computes the positive or negative root (closest to the origin)
   *> of
   *>                  z(1)        z(2)        z(3)
   *> f(x) =   rho + --------- + ---------- + ---------
   *>                 d(1)-x      d(2)-x      d(3)-x
   *>
   *> It is assumed that
   *>
   *>       if ORGATI = .true. the root is between d(2) and d(3);
   *>       otherwise it is between d(1) and d(2)
   *>
   *> This routine will be called by DLAED4 when necessary. In most cases,
   *> the root sought is the smallest in magnitude, though it might not be
   *> in some extremely rare situations.
   *> \endverbatim
   *
   *  Arguments:
   *  ==========
   *
   *> \param[in] KNITER
   *> \verbatim
   *>          KNITER is INTEGER
   *>               Refer to DLAED4 for its significance.
   *> \endverbatim
   *>
   *> \param[in] ORGATI
   *> \verbatim
   *>          ORGATI is LOGICAL
   *>               If ORGATI is true, the needed root is between d(2) and
   *>               d(3); otherwise it is between d(1) and d(2).  See
   *>               DLAED4 for further details.
   *> \endverbatim
   *>
   *> \param[in] RHO
   *> \verbatim
   *>          RHO is DOUBLE PRECISION
   *>               Refer to the equation f(x) above.
   *> \endverbatim
   *>
   *> \param[in] D
   *> \verbatim
   *>          D is DOUBLE PRECISION array, dimension (3)
   *>               D satisfies d(1) < d(2) < d(3).
   *> \endverbatim
   *>
   *> \param[in] Z
   *> \verbatim
   *>          Z is DOUBLE PRECISION array, dimension (3)
   *>               Each of the elements in z must be positive.
   *> \endverbatim
   *>
   *> \param[in] FINIT
   *> \verbatim
   *>          FINIT is DOUBLE PRECISION
   *>               The value of f at 0. It is more accurate than the one
   *>               evaluated inside this routine (if someone wants to do
   *>               so).
   *> \endverbatim
   *>
   *> \param[out] TAU
   *> \verbatim
   *>          TAU is DOUBLE PRECISION
   *>               The root of the equation f(x).
   *> \endverbatim
   *>
   *> \param[out] INFO
   *> \verbatim
   *>          INFO is INTEGER
   *>               = 0: successful exit
   *>               > 0: if INFO = 1, failure to converge
   *> \endverbatim
   *
   *  Authors:
   *  ========
   *
   *> \author Univ. of Tennessee 
   *> \author Univ. of California Berkeley 
   *> \author Univ. of Colorado Denver 
   *> \author NAG Ltd. 
   *
   *> \date November 2011
   *
   *> \ingroup auxOTHERcomputational
   *
   *> \par Further Details:
   *  =====================
   *>
   *> \verbatim
   *>
   *>  10/02/03: This version has a few statements commented out for thread
   *>  safety (machine parameters are computed on each entry). SJH.
   *>
   *>  05/10/06: Modified from a new version of Ren-Cang Li, use
   *>     Gragg-Thornton-Warner cubic convergent scheme for better stability.
   *> \endverbatim
   *
   *> \par Contributors:
   *  ==================
   *>
   *>     Ren-Cang Li, Computer Science Division, University of California
   *>     at Berkeley, USA
   *>
   *  =====================================================================
       SUBROUTINE DLAED6( KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO )        SUBROUTINE DLAED6( KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO )
 *  *
 *  -- LAPACK routine (version 3.2) --  *  -- LAPACK computational 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..--
 *     February 2007  *     November 2011
 *  *
 *     .. Scalar Arguments ..  *     .. Scalar Arguments ..
       LOGICAL            ORGATI        LOGICAL            ORGATI
Line 14 Line 154
       DOUBLE PRECISION   D( 3 ), Z( 3 )        DOUBLE PRECISION   D( 3 ), Z( 3 )
 *     ..  *     ..
 *  *
 *  Purpose  
 *  =======  
 *  
 *  DLAED6 computes the positive or negative root (closest to the origin)  
 *  of  
 *                   z(1)        z(2)        z(3)  
 *  f(x) =   rho + --------- + ---------- + ---------  
 *                  d(1)-x      d(2)-x      d(3)-x  
 *  
 *  It is assumed that  
 *  
 *        if ORGATI = .true. the root is between d(2) and d(3);  
 *        otherwise it is between d(1) and d(2)  
 *  
 *  This routine will be called by DLAED4 when necessary. In most cases,  
 *  the root sought is the smallest in magnitude, though it might not be  
 *  in some extremely rare situations.  
 *  
 *  Arguments  
 *  =========  
 *  
 *  KNITER       (input) INTEGER  
 *               Refer to DLAED4 for its significance.  
 *  
 *  ORGATI       (input) LOGICAL  
 *               If ORGATI is true, the needed root is between d(2) and  
 *               d(3); otherwise it is between d(1) and d(2).  See  
 *               DLAED4 for further details.  
 *  
 *  RHO          (input) DOUBLE PRECISION  
 *               Refer to the equation f(x) above.  
 *  
 *  D            (input) DOUBLE PRECISION array, dimension (3)  
 *               D satisfies d(1) < d(2) < d(3).  
 *  
 *  Z            (input) DOUBLE PRECISION array, dimension (3)  
 *               Each of the elements in z must be positive.  
 *  
 *  FINIT        (input) DOUBLE PRECISION  
 *               The value of f at 0. It is more accurate than the one  
 *               evaluated inside this routine (if someone wants to do  
 *               so).  
 *  
 *  TAU          (output) DOUBLE PRECISION  
 *               The root of the equation f(x).  
 *  
 *  INFO         (output) INTEGER  
 *               = 0: successful exit  
 *               > 0: if INFO = 1, failure to converge  
 *  
 *  Further Details  
 *  ===============  
 *  
 *  30/06/99: Based on contributions by  
 *     Ren-Cang Li, Computer Science Division, University of California  
 *     at Berkeley, USA  
 *  
 *  10/02/03: This version has a few statements commented out for thread  
 *  safety (machine parameters are computed on each entry). SJH.  
 *  
 *  05/10/06: Modified from a new version of Ren-Cang Li, use  
 *     Gragg-Thornton-Warner cubic convergent scheme for better stability.  
 *  
 *  =====================================================================  *  =====================================================================
 *  *
 *     .. Parameters ..  *     .. Parameters ..
Removed from v.1.8  
changed lines
  Added in v.1.9

CVSweb interface <joel.bertrand@systella.fr>