slaed6.f - Man Page
SRC/slaed6.f
Synopsis
Functions/Subroutines
subroutine slaed6 (kniter, orgati, rho, d, z, finit, tau, info)
SLAED6 used by SSTEDC. Computes one Newton step in solution of the secular equation.
Function/Subroutine Documentation
subroutine slaed6 (integer kniter, logical orgati, real rho, real, dimension( 3 ) d, real, dimension( 3 ) z, real finit, real tau, integer info)
SLAED6 used by SSTEDC. Computes one Newton step in solution of the secular equation.
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.
- Parameters
KNITER
KNITER is INTEGER Refer to SLAED4 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 SLAED4 for further details.
RHO
RHO is REAL Refer to the equation f(x) above.
D
D is REAL array, dimension (3) D satisfies d(1) < d(2) < d(3).
Z
Z is REAL array, dimension (3) Each of the elements in z must be positive.
FINIT
FINIT is 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
TAU is REAL 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.
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 139 of file slaed6.f.
Author
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Referenced By
The man page slaed6(3) is an alias of slaed6.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK