SLASQ6(3) 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).