1DLAISNAN(1)         LAPACK auxiliary routine (version 3.1)         DLAISNAN(1)
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NAME

6       DLAISNAN - i not for general use
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SYNOPSIS

9       LOGICAL FUNCTION DLAISNAN(DIN1,DIN2)
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11           DOUBLE       PRECISION DIN1,DIN2
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PURPOSE

14       This  routine  is not for general use.  It exists solely to avoid over-
15       optimization in DISNAN.
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17       DLAISNAN checks for NaNs by comparing its two arguments for inequality.
18       NaN  is  the  only floating-point value where NaN != NaN returns .TRUE.
19       To check for NaNs, pass the same variable as both arguments.
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21       Strictly speaking, Fortran does not allow aliasing  of  function  argu‐
22       ments.  So  a  compiler  must assume that the two arguments are not the
23       same variable, and the test will not be optimized away.   Interprocedu‐
24       ral  or  whole-program  optimization  may  delete this test.  The ISNAN
25       functions will be replaced by the correct Fortran 03 intrinsic once the
26       intrinsic is widely available.
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ARGUMENTS

30       DIN1     (input) DOUBLE PRECISION
31                DIN2      (input)  DOUBLE PRECISION Two numbers to compare for
32                inequality.
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36 LAPACK auxiliary routine (versionNo3v.e1m)ber 2006                     DLAISNAN(1)