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slasq5.f(3) LAPACK slasq5.f(3)

NAME

slasq5.f

SYNOPSIS

Functions/Subroutines


subroutine slasq5 (I0, N0, Z, PP, TAU, SIGMA, DMIN, DMIN1, DMIN2, DN, DNM1, DNM2, IEEE, EPS)
SLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.

Function/Subroutine Documentation

subroutine slasq5 (integer I0, integer N0, real, dimension( * ) Z, integer PP, real TAU, real SIGMA, real DMIN, real DMIN1, real DMIN2, real DN, real DNM1, real DNM2, logical IEEE, real EPS)

SLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.

Purpose: 



 SLASQ5 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 REAL 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 REAL


        This is the shift.

SIGMA



          SIGMA is REAL


        This is the accumulated shift up to this step.

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(N0), the last value of d.

DNM1



          DNM1 is REAL


        d(N0-1).

DNM2



          DNM2 is REAL


        d(N0-2).

IEEE



          IEEE is LOGICAL


        Flag for IEEE or non IEEE arithmetic.

EPS



         EPS is REAL


        This is the value of epsilon used.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 146 of file slasq5.f.

Author

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