slasq4

NAME

SLASQ4 - compute 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 )
INTEGER I0, N0, N0IN, PP, TTYPE
REAL DMIN, DMIN1, DMIN2, DN, DN1, DN2, 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.

FURTHER DETAILS