Man page - lasq5(3)

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lasq5

NAME
SYNOPSIS
Functions
Detailed Description
Function Documentation
subroutine dlasq5 (integer i0, integer n0, double precision, dimension( * )z, integer pp, double precision tau, double precision sigma, doubleprecision dmin, double precision dmin1, double precision dmin2, doubleprecision dn, double precision dnm1, double precision dnm2, logicalieee, double precision eps)
subroutine slasq5 (integer i0, integer n0, real, dimension( * ) z, integerpp, real tau, real sigma, real dmin, real dmin1, real dmin2, real dn,real dnm1, real dnm2, logical ieee, real eps)
Author

NAME

lasq5 - lasq5: dqds step

SYNOPSIS

Functions

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.
subroutine slasq5 (i0, n0, z, pp, tau, sigma, dmin, dmin1, dmin2, dn, dnm1, dnm2, ieee, eps)
SLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.

Detailed Description

Function Documentation

subroutine dlasq5 (integer i0, integer n0, double precision, dimension( * )z, integer pp, double precision tau, double precision sigma, doubleprecision dmin, double precision dmin1, double precision dmin2, doubleprecision dn, double precision dnm1, double precision dnm2, logicalieee, 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.

subroutine slasq5 (integer i0, integer n0, real, dimension( * ) z, integerpp, real tau, real sigma, real dmin, real dmin1, real dmin2, real dn,real dnm1, real dnm2, logical ieee, real eps)

SLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.

Purpose:

SLASQ5 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 REAL 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 REAL
This is the shift.

SIGMA

SIGMA is REAL
This is the accumulated shift up to this step.

DMIN

DMIN is REAL
Minimum value of d.

DMIN1

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

DMIN2

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

DN

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

DNM1

DNM1 is REAL
d(N0-1).

DNM2

DNM2 is REAL
d(N0-2).

IEEE

IEEE is LOGICAL
Flag for IEEE or non IEEE arithmetic.

EPS

EPS is REAL
This is the value of epsilon used.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Author

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