/* fortran/dznrm2.f -- translated by f2c (version 20200916).
   You must link the resulting object file with libf2c:
        on Microsoft Windows system, link with libf2c.lib;
        on Linux or Unix systems, link with .../path/to/libf2c.a -lm
        or, if you install libf2c.a in a standard place, with -lf2c -lm
        -- in that order, at the end of the command line, as in
                cc *.o -lf2c -lm
        Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,

                http://www.netlib.org/f2c/libf2c.zip
*/

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"

/* > \brief \b DZNRM2 */

/*  =========== DOCUMENTATION =========== */

/* Online html documentation available at */
/*            http://www.netlib.org/lapack/explore-html/ */

/*  Definition: */
/*  =========== */

/*       DOUBLE PRECISION FUNCTION DZNRM2(N,X,INCX) */

/*       .. Scalar Arguments .. */
/*       INTEGER INCX,N */
/*       .. */
/*       .. Array Arguments .. */
/*       COMPLEX*16 X(*) */
/*       .. */


/* > \par Purpose: */
/*  ============= */
/* > */
/* > \verbatim */
/* > */
/* > DZNRM2 returns the euclidean norm of a vector via the function */
/* > name, so that */
/* > */
/* >    DZNRM2 := sqrt( x**H*x ) */
/* > \endverbatim */

/*  Arguments: */
/*  ========== */

/* > \param[in] N */
/* > \verbatim */
/* >          N is INTEGER */
/* >         number of elements in input vector(s) */
/* > \endverbatim */
/* > */
/* > \param[in] X */
/* > \verbatim */
/* >          X is COMPLEX*16 array, dimension (N) */
/* >         complex vector with N elements */
/* > \endverbatim */
/* > */
/* > \param[in] INCX */
/* > \verbatim */
/* >          INCX is INTEGER */
/* >         storage spacing between elements of X */
/* > \endverbatim */

/*  Authors: */
/*  ======== */

/* > \author Univ. of Tennessee */
/* > \author Univ. of California Berkeley */
/* > \author Univ. of Colorado Denver */
/* > \author NAG Ltd. */

/* > \date December 2016 */

/* > \ingroup double_blas_level1 */

/* > \par Further Details: */
/*  ===================== */
/* > */
/* > \verbatim */
/* > */
/* >  -- This version written on 25-October-1982. */
/* >     Modified on 14-October-1993 to inline the call to ZLASSQ. */
/* >     Sven Hammarling, Nag Ltd. */
/* > \endverbatim */
/* > */
/*  ===================================================================== */
doublereal dznrm2_(integer *n, doublecomplex *x, integer *incx)
{
    /* System generated locals */
    integer i__1, i__2, i__3;
    doublereal ret_val, d__1;

    /* Builtin functions */
    double d_imag(doublecomplex *), sqrt(doublereal);

    /* Local variables */
    integer ix;
    doublereal ssq, temp, norm, scale;


/*  -- Reference BLAS level1 routine (version 3.7.0) -- */
/*  -- Reference BLAS is a software package provided by Univ. of Tennessee,    -- */
/*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/*     December 2016 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
    /* Parameter adjustments */
    --x;

    /* Function Body */
    if (*n < 1 || *incx < 1) {
        norm = 0.;
    } else {
        scale = 0.;
        ssq = 1.;
/*        The following loop is equivalent to this call to the LAPACK */
/*        auxiliary routine: */
/*        CALL ZLASSQ( N, X, INCX, SCALE, SSQ ) */

        i__1 = (*n - 1) * *incx + 1;
        i__2 = *incx;
        for (ix = 1; i__2 < 0 ? ix >= i__1 : ix <= i__1; ix += i__2) {
            i__3 = ix;
            if (x[i__3].r != 0.) {
                i__3 = ix;
                temp = (d__1 = x[i__3].r, abs(d__1));
                if (scale < temp) {
/* Computing 2nd power */
                    d__1 = scale / temp;
                    ssq = ssq * (d__1 * d__1) + 1.;
                    scale = temp;
                } else {
/* Computing 2nd power */
                    d__1 = temp / scale;
                    ssq += d__1 * d__1;
                }
            }
            if (d_imag(&x[ix]) != 0.) {
                temp = (d__1 = d_imag(&x[ix]), abs(d__1));
                if (scale < temp) {
/* Computing 2nd power */
                    d__1 = scale / temp;
                    ssq = ssq * (d__1 * d__1) + 1.;
                    scale = temp;
                } else {
/* Computing 2nd power */
                    d__1 = temp / scale;
                    ssq += d__1 * d__1;
                }
            }
/* L10: */
        }
        norm = scale * sqrt(ssq);
    }

    ret_val = norm;
    return ret_val;

/*     End of DZNRM2. */

} /* dznrm2_ */

#ifdef __cplusplus
        }
#endif