github.com/gonum/lapack@v0.0.0-20181123203213-e4cdc5a0bff9/internal/testdata/dsterftest/dlaisnan.f (about)

     1  *> \brief \b DLAISNAN tests input for NaN by comparing two arguments for inequality.
     2  *
     3  *  =========== DOCUMENTATION ===========
     4  *
     5  * Online html documentation available at 
     6  *            http://www.netlib.org/lapack/explore-html/ 
     7  *
     8  *> \htmlonly
     9  *> Download DLAISNAN + dependencies 
    10  *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaisnan.f"> 
    11  *> [TGZ]</a> 
    12  *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaisnan.f"> 
    13  *> [ZIP]</a> 
    14  *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaisnan.f"> 
    15  *> [TXT]</a>
    16  *> \endhtmlonly 
    17  *
    18  *  Definition:
    19  *  ===========
    20  *
    21  *       LOGICAL FUNCTION DLAISNAN( DIN1, DIN2 )
    22  * 
    23  *       .. Scalar Arguments ..
    24  *       DOUBLE PRECISION   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 September 2012
    71  *
    72  *> \ingroup auxOTHERauxiliary
    73  *
    74  *  =====================================================================
    75        LOGICAL FUNCTION DLAISNAN( DIN1, DIN2 )
    76  *
    77  *  -- LAPACK auxiliary routine (version 3.4.2) --
    78  *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
    79  *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
    80  *     September 2012
    81  *
    82  *     .. Scalar Arguments ..
    83        DOUBLE PRECISION   DIN1, DIN2
    84  *     ..
    85  *
    86  *  =====================================================================
    87  *
    88  *  .. Executable Statements ..
    89        DLAISNAN = (DIN1.NE.DIN2)
    90        RETURN
    91        END