table of contents
| dlasq4.f(3) | LAPACK | dlasq4.f(3) |
NAME¶
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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| Tue Sep 25 2012 | Version 3.4.2 |