DLASQ6(3)                  MathKeisan LAPACK routine                 DLASQ6(3)



NAME
       DLASQ6  -  one  dqd  (shift equal to zero) transform in ping-pong form,
       with protection against underflow and overflow

SYNOPSIS
       SUBROUTINE DLASQ6( I0, N0, Z, PP, DMIN, DMIN1, DMIN2, DN, DNM1, DNM2 )

           INTEGER        I0, N0, PP

           DOUBLE         PRECISION DMIN, DMIN1, DMIN2, DN, DNM1, DNM2

           DOUBLE         PRECISION Z( * )

PURPOSE
       DLASQ6 computes one dqd (shift equal to zero)  transform  in  ping-pong
       form, with protection against underflow and overflow.


ARGUMENTS
       I0    (input) INTEGER
             First index.

       N0    (input) INTEGER
             Last index.

       Z     (input) DOUBLE PRECISION array, dimension ( 4*N )
             Z holds the qd array. EMIN is stored in Z(4*N0) to avoid an extra
             argument.

       PP    (input) INTEGER
             PP=0 for ping, PP=1 for pong.

       DMIN  (output) DOUBLE PRECISION
             Minimum value of d.

             DMIN1 (output) DOUBLE PRECISION Minimum value of d, excluding  D(
             N0 ).

             DMIN2  (output) DOUBLE PRECISION Minimum value of d, excluding D(
             N0 ) and D( N0-1 ).

       DN    (output) DOUBLE PRECISION
             d(N0), the last value of d.

       DNM1  (output) DOUBLE PRECISION
             d(N0-1).

       DNM2  (output) DOUBLE PRECISION
             d(N0-2).



 LAPACK auxiliary routine (versionNo3v.e1m)ber 2006                       DLASQ6(3)