/*! \file
Copyright (c) 2003, The Regents of the University of California, through
Lawrence Berkeley National Laboratory (subject to receipt of any required
approvals from U.S. Dept. of Energy)

All rights reserved.

The source code is distributed under BSD license, see the file License.txt
at the top-level directory.
*/
#include "slu_dcomplex.h"
#include "slu_mt_Cnames.h"

double dzsum1_(int* n, doublecomplex* cx, int* incx) {
    /*  -- LAPACK auxiliary routine (version 2.0) --
           Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
           Courant Institute, Argonne National Lab, and Rice University
           October 31, 1992

        Purpose
        =======

        DZSUM1 takes the sum of the absolute values of a complex
        vector and returns a double precision result.

        Based on DZASUM from the Level 1 BLAS.
        The change is to use the 'genuine' absolute value.

        Contributed by Nick Higham for use with ZLACON.

        Arguments
        =========

        N       (input) INT
                The number of elements in the vector CX.

        CX      (input) COMPLEX*16 array, dimension (N)
                The vector whose elements will be summed.

        INCX    (input) INT
                The spacing between successive values of CX.  INCX > 0.

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

    /* Builtin functions */
    double z_abs(doublecomplex*);

    /* Local variables */
    int i, nincx;
    double stemp;

#define CX(I) cx[(I) - 1]

    stemp = 0.;
    if(*n <= 0) {
        return stemp;
    }
    if(*incx == 1) {
        goto L20;
    }

    /*     CODE FOR INCREMENT NOT EQUAL TO 1 */

    nincx = *n * *incx;
    for(i = 1; *incx < 0 ? i >= nincx : i <= nincx; i += *incx) {
        /*        NEXT LINE MODIFIED. */

        stemp += z_abs(&CX(i));
        /* L10: */
    }

    return stemp;

    /*     CODE FOR INCREMENT EQUAL TO 1 */

L20:
    for(i = 1; i <= *n; ++i) {
        /*        NEXT LINE MODIFIED. */

        stemp += z_abs(&CX(i));
        /* L30: */
    }

    return stemp;

    /*     End of DZSUM1 */

} /* dzsum1_ */
