DLASQ4
Purpose
DLASQ4 computes an approximation TAU to the smallest eigenvalue
using values of d from the previous transform.
using values of d from the previous transform.
Arguments
| I0 |
(input) INTEGER
First index.
|
| N0 |
(input) INTEGER
Last index.
|
| Z |
(input) DOUBLE PRECISION 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) DOUBLE PRECISION
Minimum value of d.
|
| DMIN1 |
(input) DOUBLE PRECISION
Minimum value of d, excluding D( N0 ).
|
| DMIN2 |
(input) DOUBLE PRECISION
Minimum value of d, excluding D( N0 ) and D( N0-1 ).
|
| DN |
(input) DOUBLE PRECISION
d(N)
|
| DN1 |
(input) DOUBLE PRECISION
d(N-1)
|
| DN2 |
(input) DOUBLE PRECISION
d(N-2)
|
| TAU |
(output) DOUBLE PRECISION
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 DLASQ4. |
Further Details
CNST1 = 9/16