NAME¶

DLASQ5 - computes one dqds transform in ping-pong form, one version for IEEE machines another for non IEEE machines

SYNOPSIS¶

SUBROUTINE DLASQ5(

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

LOGICAL IEEE INTEGER I0, N0, PP DOUBLE PRECISION DMIN, DMIN1, DMIN2, DN, DNM1, DNM2, TAU DOUBLE PRECISION Z( * )

PURPOSE¶

DLASQ5 computes one dqds transform in ping-pong form, one version for IEEE machines another for non IEEE machines.

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.

TAU (input) DOUBLE PRECISION

This is the shift.

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).

IEEE (input) LOGICAL

Flag for IEEE or non IEEE arithmetic.