redhat man page for dlaed6

DLAED6(l)								 )								 DLAED6(l)

NAME
       DLAED6  -  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 DLAED6( KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO )

	   LOGICAL	  ORGATI

	   INTEGER	  INFO, KNITER

	   DOUBLE	  PRECISION FINIT, RHO, TAU

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

LAPACK version 3.0						   15 June 2000 							 DLAED6(l)