LAPACK  3.8.0 LAPACK: Linear Algebra PACKage
dlaisnan.f
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1 *> \brief \b DLAISNAN tests input for NaN by comparing two arguments for inequality.
2 *
3 * =========== DOCUMENTATION ===========
4 *
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17 *
18 * Definition:
19 * ===========
20 *
21 * LOGICAL FUNCTION DLAISNAN( DIN1, DIN2 )
22 *
23 * .. Scalar Arguments ..
24 * DOUBLE PRECISION, INTENT(IN) :: DIN1, DIN2
25 * ..
26 *
27 *
28 *> \par Purpose:
29 * =============
30 *>
31 *> \verbatim
32 *>
33 *> This routine is not for general use. It exists solely to avoid
34 *> over-optimization in DISNAN.
35 *>
36 *> DLAISNAN checks for NaNs by comparing its two arguments for
37 *> inequality. NaN is the only floating-point value where NaN != NaN
38 *> returns .TRUE. To check for NaNs, pass the same variable as both
39 *> arguments.
40 *>
41 *> A compiler must assume that the two arguments are
42 *> not the same variable, and the test will not be optimized away.
43 *> Interprocedural or whole-program optimization may delete this
44 *> test. The ISNAN functions will be replaced by the correct
45 *> Fortran 03 intrinsic once the intrinsic is widely available.
46 *> \endverbatim
47 *
48 * Arguments:
49 * ==========
50 *
51 *> \param[in] DIN1
52 *> \verbatim
53 *> DIN1 is DOUBLE PRECISION
54 *> \endverbatim
55 *>
56 *> \param[in] DIN2
57 *> \verbatim
58 *> DIN2 is DOUBLE PRECISION
59 *> Two numbers to compare for inequality.
60 *> \endverbatim
61 *
62 * Authors:
63 * ========
64 *
65 *> \author Univ. of Tennessee
66 *> \author Univ. of California Berkeley
67 *> \author Univ. of Colorado Denver
68 *> \author NAG Ltd.
69 *
70 *> \date June 2017
71 *
72 *> \ingroup OTHERauxiliary
73 *
74 * =====================================================================
75  LOGICAL FUNCTION dlaisnan( DIN1, DIN2 )
76 *
77 * -- LAPACK auxiliary routine (version 3.7.1) --
78 * -- LAPACK is a software package provided by Univ. of Tennessee, --
79 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
80 * June 2017
81 *
82 * .. Scalar Arguments ..
83  DOUBLE PRECISION, INTENT(IN) :: DIN1, DIN2
84 * ..
85 *
86 * =====================================================================
87 *
88 * .. Executable Statements ..
89  dlaisnan = (din1.NE.din2)
90  RETURN
91  END
logical function dlaisnan(DIN1, DIN2)
DLAISNAN tests input for NaN by comparing two arguments for inequality.
Definition: dlaisnan.f:76