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.
Number of divisions.
TTYPE (output) INTEGER
Shift type.
IEEE (input) LOGICAL
Flag for IEEE or non IEEE arithmetic (passed to
SLASQ5).
Man(1) output converted with
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