slasq6()

subroutine slasq6	(	integer	i0,
		integer	n0,
		real, dimension( * )	z,
		integer	pp,
		real	dmin,
		real	dmin1,
		real	dmin2,
		real	dn,
		real	dnm1,
		real	dnm2 )

SLASQ6 computes one dqd transform in ping-pong form. Used by sbdsqr and sstegr.

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Purpose:

!>
!> SLASQ6 computes one dqd (shift equal to zero) transform in
!> ping-pong form, with protection against underflow and overflow.
!> 

Parameters

[in]	I0	!> I0 is INTEGER !> First index. !>
[in]	N0	!> N0 is INTEGER !> Last index. !>
[in]	Z	!> Z is REAL array, dimension ( 4*N ) !> Z holds the qd array. EMIN is stored in Z(4*N0) to avoid !> an extra argument. !>
[in]	PP	!> PP is INTEGER !> PP=0 for ping, PP=1 for pong. !>
[out]	DMIN	!> DMIN is REAL !> Minimum value of d. !>
[out]	DMIN1	!> DMIN1 is REAL !> Minimum value of d, excluding D( N0 ). !>
[out]	DMIN2	!> DMIN2 is REAL !> Minimum value of d, excluding D( N0 ) and D( N0-1 ). !>
[out]	DN	!> DN is REAL !> d(N0), the last value of d. !>
[out]	DNM1	!> DNM1 is REAL !> d(N0-1). !>
[out]	DNM2	!> DNM2 is REAL !> d(N0-2). !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.