DLASQ4(l) ) DLASQ4(l)
NAME
DLASQ4 - compute an approximation TAU to the smallest eigenvalue using values of d from the previous transform
SYNOPSIS
SUBROUTINE DLASQ4( I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU, TTYPE )
INTEGER I0, N0, N0IN, PP, TTYPE
DOUBLE PRECISION DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU
DOUBLE PRECISION Z( * )
PURPOSE
DLASQ4 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) 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.
FURTHER DETAILS
LAPACK version 3.0 15 June 2000 DLASQ4(l)
