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Annotation of rpl/lapack/lapack/dlaisnan.f, revision 1.8

1.5       bertrand    1:       LOGICAL FUNCTION DLAISNAN( DIN1, DIN2 )
1.1       bertrand    2: *
1.5       bertrand    3: *  -- LAPACK auxiliary routine (version 3.2.2) --
1.1       bertrand    4: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
                      5: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.5       bertrand    6: *     June 2010
1.1       bertrand    7: *
                      8: *     .. Scalar Arguments ..
1.5       bertrand    9:       DOUBLE PRECISION   DIN1, DIN2
1.1       bertrand   10: *     ..
                     11: *
                     12: *  Purpose
                     13: *  =======
                     14: *
                     15: *  This routine is not for general use.  It exists solely to avoid
                     16: *  over-optimization in DISNAN.
                     17: *
                     18: *  DLAISNAN checks for NaNs by comparing its two arguments for
                     19: *  inequality.  NaN is the only floating-point value where NaN != NaN
                     20: *  returns .TRUE.  To check for NaNs, pass the same variable as both
                     21: *  arguments.
                     22: *
                     23: *  A compiler must assume that the two arguments are
                     24: *  not the same variable, and the test will not be optimized away.
                     25: *  Interprocedural or whole-program optimization may delete this
                     26: *  test.  The ISNAN functions will be replaced by the correct
                     27: *  Fortran 03 intrinsic once the intrinsic is widely available.
                     28: *
                     29: *  Arguments
                     30: *  =========
                     31: *
1.5       bertrand   32: *  DIN1    (input) DOUBLE PRECISION
                     33: *
                     34: *  DIN2    (input) DOUBLE PRECISION
1.1       bertrand   35: *          Two numbers to compare for inequality.
                     36: *
                     37: *  =====================================================================
                     38: *
                     39: *  .. Executable Statements ..
                     40:       DLAISNAN = (DIN1.NE.DIN2)
                     41:       RETURN
                     42:       END