man slasq4 (Fonctions bibliothèques) - compute an approximation TAU to the smallest eigenvalue using values of d from the previous transform

NAME

SLASQ4 - compute an approximation TAU to the smallest eigenvalue using values of d from the previous transform

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( * )

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.