slaed6(l) [redhat man page]

SLAED6(l)								 )								 SLAED6(l)

NAME

       SLAED6  -  compute  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

SYNOPSIS

       SUBROUTINE SLAED6( KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO )

	   LOGICAL	  ORGATI

	   INTEGER	  INFO, KNITER

	   REAL 	  FINIT, RHO, TAU

	   REAL 	  D( 3 ), Z( 3 )

PURPOSE

       SLAED6 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 SLAED4 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 SLAED4 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  SLAED4  for  further
		    details.

       RHO	    (input) REAL
		    Refer to the equation f(x) above.

       D	    (input) REAL array, dimension (3)
		    D satisfies d(1) < d(2) < d(3).

       Z	    (input) REAL array, dimension (3)
		    Each of the elements in z must be positive.

       FINIT	    (input) REAL
		    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) REAL
		    The root of the equation f(x).

       INFO	    (output) INTEGER
		    = 0: successful exit
		    > 0: if INFO = 1, failure to converge

FURTHER DETAILS

       Based on contributions by
	  Ren-Cang Li, Computer Science Division, University of California
	  at Berkeley, USA

LAPACK version 3.0						   15 June 2000 							 SLAED6(l)

dlaed6.f(3)							      LAPACK							       dlaed6.f(3)

NAME

       dlaed6.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dlaed6 (KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO)
	   DLAED6 used by sstedc. Computes one Newton step in solution of the secular equation.

Function/Subroutine Documentation
   subroutine dlaed6 (integerKNITER, logicalORGATI, double precisionRHO, double precision, dimension( 3 )D, double precision, dimension( 3 )Z,
       double precisionFINIT, double precisionTAU, integerINFO)
       DLAED6 used by sstedc. Computes one Newton step in solution of the secular equation.

       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.

       Parameters:
	   KNITER

		     KNITER is INTEGER
			  Refer to DLAED4 for its significance.

	   ORGATI

		     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.

	   RHO

		     RHO is DOUBLE PRECISION
			  Refer to the equation f(x) above.

	   D

		     D is DOUBLE PRECISION array, dimension (3)
			  D satisfies d(1) < d(2) < d(3).

	   Z

		     Z is DOUBLE PRECISION array, dimension (3)
			  Each of the elements in z must be positive.

	   FINIT

		     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).

	   TAU

		     TAU is DOUBLE PRECISION
			  The root of the equation f(x).

	   INFO

		     INFO is INTEGER
			  = 0: successful exit
			  > 0: if INFO = 1, failure to converge

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Further Details:

	     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.

       Contributors:
	   Ren-Cang Li, Computer Science Division, University of California at Berkeley, USA

       Definition at line 141 of file dlaed6.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						       dlaed6.f(3)