convert linalg library from Fortran to C++

lib/linalg/fortran/disnan.f

@@ -0,0 +1,77 @@
+*> \brief \b DISNAN tests input for NaN.
+*
+*  =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+*            http://www.netlib.org/lapack/explore-html/
+*
+*> \htmlonly
+*> Download DISNAN + dependencies
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/disnan.f">
+*> [TGZ]</a>
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/disnan.f">
+*> [ZIP]</a>
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/disnan.f">
+*> [TXT]</a>
+*> \endhtmlonly
+*
+*  Definition:
+*  ===========
+*
+*       LOGICAL FUNCTION DISNAN( DIN )
+*
+*       .. Scalar Arguments ..
+*       DOUBLE PRECISION, INTENT(IN) :: DIN
+*       ..
+*
+*
+*> \par Purpose:
+*  =============
+*>
+*> \verbatim
+*>
+*> DISNAN returns .TRUE. if its argument is NaN, and .FALSE.
+*> otherwise.  To be replaced by the Fortran 2003 intrinsic in the
+*> future.
+*> \endverbatim
+*
+*  Arguments:
+*  ==========
+*
+*> \param[in] DIN
+*> \verbatim
+*>          DIN is DOUBLE PRECISION
+*>          Input to test for NaN.
+*> \endverbatim
+*
+*  Authors:
+*  ========
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \ingroup OTHERauxiliary
+*
+*  =====================================================================
+      LOGICAL FUNCTION DISNAN( DIN )
+*
+*  -- LAPACK auxiliary routine --
+*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
+*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+*
+*     .. Scalar Arguments ..
+      DOUBLE PRECISION, INTENT(IN) :: DIN
+*     ..
+*
+*  =====================================================================
+*
+*  .. External Functions ..
+      LOGICAL DLAISNAN
+      EXTERNAL DLAISNAN
+*  ..
+*  .. Executable Statements ..
+      DISNAN = DLAISNAN(DIN,DIN)
+      RETURN
+      END