DLAZQ4(3f)

NAME
DLAZQ4 - an approximation TAU to the smallest eigenvalue using values of d from the previous transform

SYNOPSIS

SUBROUTINE DLAZQ4(
    I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU, TTYPE, G )

INTEGER
    I0, N0, N0IN, PP, TTYPE

DOUBLE
    PRECISION DMIN, DMIN1, DMIN2, DN, DN1, DN2, G, TAU

DOUBLE
    PRECISION Z( * )

PURPOSE
DLAZQ4 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.
N0IN (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) DOUBLE PRECISION
      G is passed as an argument in order to save its value between
      calls to DLAZQ4

FURTHER DETAILS
This is a thread safe version of DLASQ4, which passes G through the argument list in place of declaring G in a SAVE statment.