SLASQ4(3f)          LAPACK auxiliary routine (version 3.1)          SLASQ4(3f)



NAME
       SLASQ4 - 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.

       N0IN  (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
 LAPACK auxiliary routine (versioNovember 2006                      SLASQ4(3f)
