1*> \brief \b DLCTES
2*
3*  =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6*            http://www.netlib.org/lapack/explore-html/
7*
8*  Definition:
9*  ===========
10*
11*       LOGICAL          FUNCTION DLCTES( ZR, ZI, D )
12*
13*       .. Scalar Arguments ..
14*       DOUBLE PRECISION   D, ZI, ZR
15*       ..
16*
17*
18*> \par Purpose:
19*  =============
20*>
21*> \verbatim
22*>
23*> DLCTES returns .TRUE. if the eigenvalue (ZR/D) + sqrt(-1)*(ZI/D)
24*> is to be selected (specifically, in this subroutine, if the real
25*> part of the eigenvalue is negative), and otherwise it returns
26*> .FALSE..
27*>
28*> It is used by the test routine DDRGES to test whether the driver
29*> routine DGGES succesfully sorts eigenvalues.
30*> \endverbatim
31*
32*  Arguments:
33*  ==========
34*
35*> \param[in] ZR
36*> \verbatim
37*>          ZR is DOUBLE PRECISION
38*>          The numerator of the real part of a complex eigenvalue
39*>          (ZR/D) + i*(ZI/D).
40*> \endverbatim
41*>
42*> \param[in] ZI
43*> \verbatim
44*>          ZI is DOUBLE PRECISION
45*>          The numerator of the imaginary part of a complex eigenvalue
46*>          (ZR/D) + i*(ZI).
47*> \endverbatim
48*>
49*> \param[in] D
50*> \verbatim
51*>          D is DOUBLE PRECISION
52*>          The denominator part of a complex eigenvalue
53*>          (ZR/D) + i*(ZI/D).
54*> \endverbatim
55*
56*  Authors:
57*  ========
58*
59*> \author Univ. of Tennessee
60*> \author Univ. of California Berkeley
61*> \author Univ. of Colorado Denver
62*> \author NAG Ltd.
63*
64*> \date November 2011
65*
66*> \ingroup double_eig
67*
68*  =====================================================================
69      LOGICAL          FUNCTION DLCTES( ZR, ZI, D )
70*
71*  -- LAPACK test routine (version 3.4.0) --
72*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
73*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
74*     November 2011
75*
76*     .. Scalar Arguments ..
77      DOUBLE PRECISION   D, ZI, ZR
78*     ..
79*
80*  =====================================================================
81*
82*     .. Parameters ..
83      DOUBLE PRECISION   ZERO, ONE
84      PARAMETER          ( ZERO = 0.0D+0, ONE = 1.0D+0 )
85*     ..
86*     .. Intrinsic Functions ..
87      INTRINSIC          SIGN
88*     ..
89*     .. Executable Statements ..
90*
91      IF( D.EQ.ZERO ) THEN
92         DLCTES = ( ZR.LT.ZERO )
93      ELSE
94         DLCTES = ( SIGN( ONE, ZR ).NE.SIGN( ONE, D ) )
95      END IF
96*
97      RETURN
98*
99*     End of DLCTES
100*
101      END
102