slasq3

Langue: en

Version: 325876 (ubuntu - 08/07/09)

Section: 3 (Bibliothèques de fonctions)

Sommaire

NAME

SLASQ3 - check for deflation, computes a shift (TAU) and calls dqds

SYNOPSIS

SUBROUTINE SLASQ3(
I0, N0, Z, PP, DMIN, SIGMA, DESIG, QMAX, NFAIL, ITER, NDIV, IEEE )

    
LOGICAL IEEE

    
INTEGER I0, ITER, N0, NDIV, NFAIL, PP

    
REAL DESIG, DMIN, QMAX, SIGMA

    
REAL Z( * )

PURPOSE

SLASQ3 checks for deflation, computes a shift (TAU) and calls dqds. In case of failure it changes shifts, and tries again until output is positive.

ARGUMENTS

I0 (input) INTEGER
First index.
N0 (input) INTEGER
Last index.
Z (input) REAL array, dimension ( 4*N )
Z holds the qd array.
PP (input) INTEGER
PP=0 for ping, PP=1 for pong.
DMIN (output) REAL
Minimum value of d.
SIGMA (output) REAL
Sum of shifts used in current segment.
DESIG (input/output) REAL
Lower order part of SIGMA
QMAX (input) REAL
Maximum value of q.
NFAIL (output) INTEGER
Number of times shift was too big.
ITER (output) INTEGER
Number of iterations.
NDIV (output) INTEGER
Number of divisions.
TTYPE (output) INTEGER
Shift type.
IEEE (input) LOGICAL
Flag for IEEE or non IEEE arithmetic (passed to SLASQ5).