slasq3.f(3) LAPACK slasq3.f(3)
NAME
slasq3.f -
SYNOPSIS
Functions/Subroutines
subroutine slasq3 (I0, N0, Z, PP, DMIN, SIGMA, DESIG, QMAX, NFAIL, ITER, NDIV, IEEE, TTYPE, DMIN1, DMIN2, DN, DN1, DN2, G, TAU)
SLASQ3
Function/Subroutine Documentation
subroutine slasq3 (integerI0, integerN0, real, dimension( * )Z, integerPP, realDMIN, realSIGMA, realDESIG, realQMAX, integerNFAIL, integerITER,
integerNDIV, logicalIEEE, integerTTYPE, realDMIN1, realDMIN2, realDN, realDN1, realDN2, realG, realTAU)
SLASQ3
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.
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.
PP
PP is INTEGER
PP=0 for ping, PP=1 for pong.
PP=2 indicates that flipping was applied to the Z array
and that the initial tests for deflation should not be
performed.
DMIN
DMIN is REAL
Minimum value of d.
SIGMA
SIGMA is REAL
Sum of shifts used in current segment.
DESIG
DESIG is REAL
Lower order part of SIGMA
QMAX
QMAX is REAL
Maximum value of q.
NFAIL
NFAIL is INTEGER
Number of times shift was too big.
ITER
ITER is INTEGER
Number of iterations.
NDIV
NDIV is INTEGER
Number of divisions.
IEEE
IEEE is LOGICAL
Flag for IEEE or non IEEE arithmetic (passed to SLASQ5).
TTYPE
TTYPE is INTEGER
Shift type.
DMIN1
DMIN1 is REAL
DMIN2
DMIN2 is REAL
DN
DN is REAL
DN1
DN1 is REAL
DN2
DN2 is REAL
G
G is REAL
TAU
TAU is REAL
These are passed as arguments in order to save their values
between calls to SLASQ3.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
April 2012
Definition at line 181 of file slasq3.f.
Author
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Version 3.4.1 Sun May 26 2013 slasq3.f(3)