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Annotation of rpl/lapack/lapack/dlaisnan.f, revision 1.3

1.1       bertrand    1:       LOGICAL FUNCTION DLAISNAN(DIN1,DIN2)
                      2: *
                      3: *  -- LAPACK auxiliary routine (version 3.2) --
                      4: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
                      5: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
                      6: *     November 2006
                      7: *
                      8: *     .. Scalar Arguments ..
                      9:       DOUBLE PRECISION DIN1,DIN2
                     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: *
                     32: *  DIN1     (input) DOUBLE PRECISION
                     33: *  DIN2     (input) DOUBLE PRECISION
                     34: *          Two numbers to compare for inequality.
                     35: *
                     36: *  =====================================================================
                     37: *
                     38: *  .. Executable Statements ..
                     39:       DLAISNAN = (DIN1.NE.DIN2)
                     40:       RETURN
                     41:       END