NAME
SLASQ4 - computes an approximation TAU to the smallest eigenvalue using values of d from the previous transform
SYNOPSIS
- SUBROUTINE SLASQ4(
-
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
SLASQ4 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.
NOIN (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 SLASQ4.