92 lines
2.5 KiB
Fortran
92 lines
2.5 KiB
Fortran
*> \brief \b DLAISNAN tests input for NaN by comparing two arguments for inequality.
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*
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* =========== DOCUMENTATION ===========
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*
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* Online html documentation available at
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* http://www.netlib.org/lapack/explore-html/
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*
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*> \htmlonly
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*> Download DLAISNAN + dependencies
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaisnan.f">
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*> [TGZ]</a>
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaisnan.f">
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*> [ZIP]</a>
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaisnan.f">
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*> [TXT]</a>
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*> \endhtmlonly
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*
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* Definition:
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* ===========
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*
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* LOGICAL FUNCTION DLAISNAN( DIN1, DIN2 )
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*
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* .. Scalar Arguments ..
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* DOUBLE PRECISION DIN1, DIN2
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* ..
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*
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*
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*> \par Purpose:
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* =============
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*>
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*> \verbatim
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*>
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*> This routine is not for general use. It exists solely to avoid
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*> over-optimization in DISNAN.
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*>
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*> DLAISNAN checks for NaNs by comparing its two arguments for
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*> inequality. NaN is the only floating-point value where NaN != NaN
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*> returns .TRUE. To check for NaNs, pass the same variable as both
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*> arguments.
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*>
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*> A compiler must assume that the two arguments are
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*> not the same variable, and the test will not be optimized away.
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*> Interprocedural or whole-program optimization may delete this
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*> test. The ISNAN functions will be replaced by the correct
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*> Fortran 03 intrinsic once the intrinsic is widely available.
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*> \endverbatim
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*
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* Arguments:
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* ==========
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*
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*> \param[in] DIN1
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*> \verbatim
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*> DIN1 is DOUBLE PRECISION
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*> \endverbatim
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*>
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*> \param[in] DIN2
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*> \verbatim
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*> DIN2 is DOUBLE PRECISION
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*> Two numbers to compare for inequality.
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*> \endverbatim
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*
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* Authors:
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* ========
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*
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*> \author Univ. of Tennessee
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*> \author Univ. of California Berkeley
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*> \author Univ. of Colorado Denver
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*> \author NAG Ltd.
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*
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*> \date September 2012
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*
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*> \ingroup auxOTHERauxiliary
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*
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* =====================================================================
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LOGICAL FUNCTION DLAISNAN( DIN1, DIN2 )
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*
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* -- LAPACK auxiliary routine (version 3.4.2) --
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* -- LAPACK is a software package provided by Univ. of Tennessee, --
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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* September 2012
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*
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* .. Scalar Arguments ..
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DOUBLE PRECISION DIN1, DIN2
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* ..
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*
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* =====================================================================
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*
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* .. Executable Statements ..
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DLAISNAN = (DIN1.NE.DIN2)
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RETURN
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END
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