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dlasq5.f(3) LAPACK dlasq5.f(3)

NAME

dlasq5.f

SYNOPSIS

Functions/Subroutines


subroutine dlasq5 (I0, N0, Z, PP, TAU, SIGMA, DMIN, DMIN1, DMIN2, DN, DNM1, DNM2, IEEE, EPS)
DLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.

Function/Subroutine Documentation

subroutine dlasq5 (integer I0, integer N0, double precision, dimension( * ) Z, integer PP, double precision TAU, double precision SIGMA, double precision DMIN, double precision DMIN1, double precision DMIN2, double precision DN, double precision DNM1, double precision DNM2, logical IEEE, double precision EPS)

DLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.

Purpose:


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

Parameters:

I0


I0 is INTEGER
First index.

N0


N0 is INTEGER
Last index.

Z


Z is DOUBLE PRECISION array, dimension ( 4*N )
Z holds the qd array. EMIN is stored in Z(4*N0) to avoid
an extra argument.

PP


PP is INTEGER
PP=0 for ping, PP=1 for pong.

TAU


TAU is DOUBLE PRECISION
This is the shift.

SIGMA


SIGMA is DOUBLE PRECISION
This is the accumulated shift up to this step.

DMIN


DMIN is DOUBLE PRECISION
Minimum value of d.

DMIN1


DMIN1 is DOUBLE PRECISION
Minimum value of d, excluding D( N0 ).

DMIN2


DMIN2 is DOUBLE PRECISION
Minimum value of d, excluding D( N0 ) and D( N0-1 ).

DN


DN is DOUBLE PRECISION
d(N0), the last value of d.

DNM1


DNM1 is DOUBLE PRECISION
d(N0-1).

DNM2


DNM2 is DOUBLE PRECISION
d(N0-2).

IEEE


IEEE is LOGICAL
Flag for IEEE or non IEEE arithmetic.

EPS


EPS is DOUBLE PRECISION
This is the value of epsilon used.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

June 2017

Definition at line 146 of file dlasq5.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Tue Nov 14 2017 Version 3.8.0