dlasq4.f man page

dlasq4.f —

Synopsis

Functions/Subroutines

subroutine dlasq4 (I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU, TTYPE, G)
DLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr.

Function/Subroutine Documentation

subroutine dlasq4 (integerI0, integerN0, double precision, dimension( * )Z, integerPP, integerN0IN, double precisionDMIN, double precisionDMIN1, double precisionDMIN2, double precisionDN, double precisionDN1, double precisionDN2, double precisionTAU, integerTTYPE, double precisionG)

DLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr.

Purpose:

DLASQ4 computes an approximation TAU to the smallest eigenvalue
using values of d from the previous transform.

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.

PP

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

N0IN

  N0IN is INTEGER
The value of N0 at start of EIGTEST.

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(N)

DN1

  DN1 is DOUBLE PRECISION
d(N-1)

DN2

  DN2 is DOUBLE PRECISION
d(N-2)

TAU

  TAU is DOUBLE PRECISION
This is the shift.

TTYPE

  TTYPE is INTEGER
Shift type.

G

  G is REAL
G is passed as an argument in order to save its value between
calls to DLASQ4.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Further Details:

CNST1 = 9/16

Definition at line 151 of file dlasq4.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dlasq4(3) is an alias of dlasq4.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK