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/* dzsum1.f -- translated by f2c (version 20061008).
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
*/
#include "f2c.h"
#include "blaswrap.h"
doublereal dzsum1_(integer *n, doublecomplex *cx, integer *incx)
{
/* System generated locals */
integer i__1, i__2;
doublereal ret_val;
/* Builtin functions */
double z_abs(doublecomplex *);
/* Local variables */
integer i__, nincx;
doublereal stemp;
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* 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) INTEGER */
/* The number of elements in the vector CX. */
/* CX (input) COMPLEX*16 array, dimension (N) */
/* The vector whose elements will be summed. */
/* INCX (input) INTEGER */
/* The spacing between successive values of CX. INCX > 0. */
/* ===================================================================== */
/* .. Local Scalars .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Parameter adjustments */
--cx;
/* Function Body */
ret_val = 0.;
stemp = 0.;
if (*n <= 0) {
return ret_val;
}
if (*incx == 1) {
goto L20;
}
/* CODE FOR INCREMENT NOT EQUAL TO 1 */
nincx = *n * *incx;
i__1 = nincx;
i__2 = *incx;
for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
/* NEXT LINE MODIFIED. */
stemp += z_abs(&cx[i__]);
/* L10: */
}
ret_val = stemp;
return ret_val;
/* CODE FOR INCREMENT EQUAL TO 1 */
L20:
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
/* NEXT LINE MODIFIED. */
stemp += z_abs(&cx[i__]);
/* L30: */
}
ret_val = stemp;
return ret_val;
/* End of DZSUM1 */
} /* dzsum1_ */
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