dlasq5.f man page

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.

Referenced By

dlasq5(3) is an alias of dlasq5.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK