SYNOPSIS

SUBROUTINE DLASQ4(

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

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.
G (input/output) REAL

      G is passed as an argument in order to save its value between
      calls to DLASQ4.

FURTHER DETAILS