LAPACK  3.10.1
LAPACK: Linear Algebra PACKage
clctes.f
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1 *> \brief \b CLCTES
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 CLCTES( Z, D )
12 *
13 * .. Scalar Arguments ..
14 * COMPLEX D, Z
15 * ..
16 *
17 *
18 *> \par Purpose:
19 * =============
20 *>
21 *> \verbatim
22 *>
23 *> CLCTES returns .TRUE. if the eigenvalue Z/D is to be selected
24 *> (specifically, in this subroutine, if the real part of the
25 *> eigenvalue is negative), and otherwise it returns .FALSE..
26 *>
27 *> It is used by the test routine CDRGES to test whether the driver
28 *> routine CGGES successfully sorts eigenvalues.
29 *> \endverbatim
30 *
31 * Arguments:
32 * ==========
33 *
34 *> \param[in] Z
35 *> \verbatim
36 *> Z is COMPLEX
37 *> The numerator part of a complex eigenvalue Z/D.
38 *> \endverbatim
39 *>
40 *> \param[in] D
41 *> \verbatim
42 *> D is COMPLEX
43 *> The denominator part of a complex eigenvalue Z/D.
44 *> \endverbatim
45 *
46 * Authors:
47 * ========
48 *
49 *> \author Univ. of Tennessee
50 *> \author Univ. of California Berkeley
51 *> \author Univ. of Colorado Denver
52 *> \author NAG Ltd.
53 *
54 *> \ingroup complex_eig
55 *
56 * =====================================================================
57  LOGICAL FUNCTION clctes( Z, D )
58 *
59 * -- LAPACK test routine --
60 * -- LAPACK is a software package provided by Univ. of Tennessee, --
61 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
62 *
63 * .. Scalar Arguments ..
64  COMPLEX d, z
65 * ..
66 *
67 * =====================================================================
68 *
69 * .. Parameters ..
70 *
71  REAL zero, one
72  parameter( zero = 0.0e+0, one = 1.0e+0 )
73  COMPLEX czero
74  parameter( czero = ( 0.0e+0, 0.0e+0 ) )
75 * ..
76 * .. Local Scalars ..
77  REAL zmax
78 * ..
79 * .. Intrinsic Functions ..
80  INTRINSIC abs, aimag, max, real, sign
81 * ..
82 * .. Executable Statements ..
83 *
84  IF( d.EQ.czero ) THEN
85  clctes = ( real( z ).LT.zero )
86  ELSE
87  IF( real( z ).EQ.zero .OR. real( d ).EQ.zero ) THEN
88  clctes = ( sign( one, aimag( z ) ).NE.
89  $ sign( one, aimag( d ) ) )
90  ELSE IF( aimag( z ).EQ.zero .OR. aimag( d ).EQ.zero ) THEN
91  clctes = ( sign( one, real( z ) ).NE.
92  $ sign( one, real( d ) ) )
93  ELSE
94  zmax = max( abs( real( z ) ), abs( aimag( z ) ) )
95  clctes = ( ( real( z ) / zmax )*real( d )+
96  $ ( aimag( z ) / zmax )*aimag( d ).LT.zero )
97  END IF
98  END IF
99 *
100  RETURN
101 *
102 * End of CLCTES
103 *
104  END
logical function clctes(Z, D)
CLCTES
Definition: clctes.f:58