slasq4.f man page

slasq4.f —

Synopsis

Functions/Subroutines

subroutine slasq4 (I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU, TTYPE, G)
SLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr.

Function/Subroutine Documentation

subroutine slasq4 (integerI0, integerN0, real, dimension( * )Z, integerPP, integerN0IN, realDMIN, realDMIN1, realDMIN2, realDN, realDN1, realDN2, realTAU, integerTTYPE, realG)

SLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr.

Purpose:

SLASQ4 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 REAL 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 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(N)

DN1

  DN1 is REAL
d(N-1)

DN2

  DN2 is REAL
d(N-2)

TAU

  TAU is REAL
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 SLASQ4.

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 slasq4.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

slasq4(3) is an alias of slasq4.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK