dlasq5.f (3) Linux Manual Page

dlasq5.f –

Synopsis

Functions/Subroutines

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.

Function/Subroutine Documentation

subroutine dlasq5 (integerI0, integerN0, double precision, dimension( * )Z, integerPP, double precisionTAU, double precisionSIGMA, double precisionDMIN, double precisionDMIN1, double precisionDMIN2, double precisionDN, double precisionDNM1, double precisionDNM2, logicalIEEE, double precisionEPS)

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.

Date:

September 2012

Definition at line 144 of file dlasq5.f.

Author

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