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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 (integerI0, integerN0, double precision, dimension( * )Z, integerPP, double precisionTAU, double precisionSIGMA, double precisionDMIN, double precisionDMIN1, double precisionDMIN2, double precisionDN, double precisionDNM1, double precisionDNM2, logicalIEEE, double precisionEPS)

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:

September 2012

Definition at line 144 of file dlasq5.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Tue Sep 25 2012 Version 3.4.2