DLASQ4 (3) Linux Manual 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

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