NAME
DLASQ6 - computes 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).