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/* izmax1.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"
integer izmax1_(integer *n, doublecomplex *cx, integer *incx)
{
/* System generated locals */
integer ret_val, i__1;
/* Builtin functions */
double z_abs(doublecomplex *);
/* Local variables */
integer i__, ix;
doublereal smax;
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* IZMAX1 finds the index of the element whose real part has maximum */
/* absolute value. */
/* Based on IZAMAX from 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 >= 1. */
/* ===================================================================== */
/* .. Local Scalars .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Statement Functions .. */
/* .. */
/* .. Statement Function definitions .. */
/* NEXT LINE IS THE ONLY MODIFICATION. */
/* .. */
/* .. Executable Statements .. */
/* Parameter adjustments */
--cx;
/* Function Body */
ret_val = 0;
if (*n < 1) {
return ret_val;
}
ret_val = 1;
if (*n == 1) {
return ret_val;
}
if (*incx == 1) {
goto L30;
}
/* CODE FOR INCREMENT NOT EQUAL TO 1 */
ix = 1;
smax = z_abs(&cx[1]);
ix += *incx;
i__1 = *n;
for (i__ = 2; i__ <= i__1; ++i__) {
if (z_abs(&cx[ix]) <= smax) {
goto L10;
}
ret_val = i__;
smax = z_abs(&cx[ix]);
L10:
ix += *incx;
/* L20: */
}
return ret_val;
/* CODE FOR INCREMENT EQUAL TO 1 */
L30:
smax = z_abs(&cx[1]);
i__1 = *n;
for (i__ = 2; i__ <= i__1; ++i__) {
if (z_abs(&cx[i__]) <= smax) {
goto L40;
}
ret_val = i__;
smax = z_abs(&cx[i__]);
L40:
;
}
return ret_val;
/* End of IZMAX1 */
} /* izmax1_ */
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