convert linalg library from Fortran to C++

lib/linalg/fortran/dcabs1.f

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+*> \brief \b DCABS1
+*
+*  =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+*            http://www.netlib.org/lapack/explore-html/
+*
+*  Definition:
+*  ===========
+*
+*       DOUBLE PRECISION FUNCTION DCABS1(Z)
+*
+*       .. Scalar Arguments ..
+*       COMPLEX*16 Z
+*       ..
+*       ..
+*
+*
+*> \par Purpose:
+*  =============
+*>
+*> \verbatim
+*>
+*> DCABS1 computes |Re(.)| + |Im(.)| of a double complex number
+*> \endverbatim
+*
+*  Arguments:
+*  ==========
+*
+*> \param[in] Z
+*> \verbatim
+*>          Z is COMPLEX*16
+*> \endverbatim
+*
+*  Authors:
+*  ========
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \ingroup double_blas_level1
+*
+*  =====================================================================
+      DOUBLE PRECISION FUNCTION DCABS1(Z)
+*
+*  -- Reference BLAS level1 routine --
+*  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
+*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+*
+*     .. Scalar Arguments ..
+      COMPLEX*16 Z
+*     ..
+*     ..
+*  =====================================================================
+*
+*     .. Intrinsic Functions ..
+      INTRINSIC ABS,DBLE,DIMAG
+*
+      DCABS1 = ABS(DBLE(Z)) + ABS(DIMAG(Z))
+      RETURN
+*
+*     End of DCABS1
+*
+      END