LAPACK  3.10.1 LAPACK: Linear Algebra PACKage
slctsx.f
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1 *> \brief \b SLCTSX
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 SLCTSX( AR, AI, BETA )
12 *
13 * .. Scalar Arguments ..
14 * REAL AI, AR, BETA
15 * ..
16 *
17 *
18 *> \par Purpose:
19 * =============
20 *>
21 *> \verbatim
22 *>
23 *> This function is used to determine what eigenvalues will be
24 *> selected. If this is part of the test driver SDRGSX, do not
25 *> change the code UNLESS you are testing input examples and not
26 *> using the built-in examples.
27 *> \endverbatim
28 *
29 * Arguments:
30 * ==========
31 *
32 *> \param[in] AR
33 *> \verbatim
34 *> AR is REAL
35 *> The numerator of the real part of a complex eigenvalue
36 *> (AR/BETA) + i*(AI/BETA).
37 *> \endverbatim
38 *>
39 *> \param[in] AI
40 *> \verbatim
41 *> AI is REAL
42 *> The numerator of the imaginary part of a complex eigenvalue
43 *> (AR/BETA) + i*(AI).
44 *> \endverbatim
45 *>
46 *> \param[in] BETA
47 *> \verbatim
48 *> BETA is REAL
49 *> The denominator part of a complex eigenvalue
50 *> (AR/BETA) + i*(AI/BETA).
51 *> \endverbatim
52 *
53 * Authors:
54 * ========
55 *
56 *> \author Univ. of Tennessee
57 *> \author Univ. of California Berkeley
58 *> \author Univ. of Colorado Denver
59 *> \author NAG Ltd.
60 *
61 *> \ingroup single_eig
62 *
63 * =====================================================================
64  LOGICAL FUNCTION slctsx( AR, AI, BETA )
65 *
66 * -- LAPACK test routine --
67 * -- LAPACK is a software package provided by Univ. of Tennessee, --
68 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
69 *
70 * .. Scalar Arguments ..
71  REAL ai, ar, beta
72 * ..
73 *
74 * =====================================================================
75 *
76 * .. Scalars in Common ..
77  LOGICAL fs
78  INTEGER i, m, mplusn, n
79 * ..
80 * .. Common blocks ..
81  COMMON / mn / m, n, mplusn, i, fs
82 * ..
83 * .. Save statement ..
84  SAVE
85 * ..
86 * .. Executable Statements ..
87 *
88  IF( fs ) THEN
89  i = i + 1
90  IF( i.LE.m ) THEN
91  slctsx = .false.
92  ELSE
93  slctsx = .true.
94  END IF
95  IF( i.EQ.mplusn ) THEN
96  fs = .false.
97  i = 0
98  END IF
99  ELSE
100  i = i + 1
101  IF( i.LE.n ) THEN
102  slctsx = .true.
103  ELSE
104  slctsx = .false.
105  END IF
106  IF( i.EQ.mplusn ) THEN
107  fs = .true.
108  i = 0
109  END IF
110  END IF
111 *
112 * IF( AR/BETA.GT.0.0 )THEN
113 * SLCTSX = .TRUE.
114 * ELSE
115 * SLCTSX = .FALSE.
116 * END IF
117 *
118  RETURN
119 *
120 * End of SLCTSX
121 *
122  END
logical function slctsx(AR, AI, BETA)
SLCTSX
Definition: slctsx.f:65