NAME

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

SYNOPSIS

SUBROUTINE SLASQ6(

I0, N0, Z, PP, DMIN, DMIN1, DMIN2, DN, DNM1, DNM2 )

INTEGER I0, N0, PP REAL DMIN, DMIN1, DMIN2, DN, DNM1, DNM2 REAL Z( * )

PURPOSE

SLASQ6 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) REAL 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) REAL

Minimum value of d. DMIN1 (output) REAL Minimum value of d, excluding D( N0 ). DMIN2 (output) REAL Minimum value of d, excluding D( N0 ) and D( N0-1 ).

DN (output) REAL

d(N0), the last value of d.

DNM1 (output) REAL

d(N0-1).

DNM2 (output) REAL

d(N0-2).