SLAZQ4(1) LAPACK auxiliary routine (version 3.1) SLAZQ4(1)NAME
SLAZQ4 - an approximation TAU to the smallest eigenvalue using values
of d from the previous transform
SYNOPSIS
SUBROUTINE SLAZQ4( I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, DN1,
DN2, TAU, TTYPE, G )
INTEGER I0, N0, N0IN, PP, TTYPE
REAL DMIN, DMIN1, DMIN2, DN, DN1, DN2, G, TAU
REAL Z( * )
PURPOSE
SLAZQ4 computes an approximation TAU to the smallest eigenvalue using
values of d from the previous transform.
I0 (input) INTEGER
First index.
N0 (input) INTEGER
Last index.
Z (input) REAL array, dimension ( 4*N )
Z holds the qd array.
PP (input) INTEGER
PP=0 for ping, PP=1 for pong.
N0IN (input) INTEGER
The value of N0 at start of EIGTEST.
DMIN (input) REAL
Minimum value of d.
DMIN1 (input) REAL
Minimum value of d, excluding D( N0 ).
DMIN2 (input) REAL
Minimum value of d, excluding D( N0 ) and D( N0-1 ).
DN (input) REAL
d(N)
DN1 (input) REAL
d(N-1)
DN2 (input) REAL
d(N-2)
TAU (output) REAL
This is the shift.
TTYPE (output) INTEGER
Shift type.
G (input/output) REAL
G is passed as an argument in order to save its value between
calls to SLAZQ4
FURTHER DETAILS
This is a thread safe version of SLASQ4, which passes G through the
argument list in place of declaring G in a SAVE statment.
LAPACK auxiliary routine (versioOctober 2006 SLAZQ4(1)
