idamax.c

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/* IDAMAX.F -- translated by f2c (version 19941215).
   You must link the resulting object file with the libraries:
        -lf2c -lm   (in that order)
*/

#include "f2c.h"

integer idamax_(n, dx, incx)
integer *n;
doublereal *dx;
integer *incx;
{
    /* System generated locals */
    integer ret_val, i__1;
    doublereal d__1;

    /* Local variables */
    static doublereal dmax__;
    static integer i, ix;


/*     finds the index of element having max. absolute value. */
/*     jack dongarra, linpack, 3/11/78. */
/*     modified 3/93 to return if incx .le. 0. */


    /* Parameter adjustments */
    --dx;

    /* Function Body */
    ret_val = 0;
    if (*n < 1 || *incx <= 0) {
        return ret_val;
    }
    ret_val = 1;
    if (*n == 1) {
        return ret_val;
    }
    if (*incx == 1) {
        goto L20;
    }

/*        code for increment not equal to 1 */

    ix = 1;
    dmax__ = abs(dx[1]);
    ix += *incx;
    i__1 = *n;
    for (i = 2; i <= i__1; ++i) {
        if ((d__1 = dx[ix], abs(d__1)) <= dmax__) {
            goto L5;
        }
        ret_val = i;
        dmax__ = (d__1 = dx[ix], abs(d__1));
L5:
        ix += *incx;
/* L10: */
    }
    return ret_val;

/*        code for increment equal to 1 */

L20:
    dmax__ = abs(dx[1]);
    i__1 = *n;
    for (i = 2; i <= i__1; ++i) {
        if ((d__1 = dx[i], abs(d__1)) <= dmax__) {
            goto L30;
        }
        ret_val = i;
        dmax__ = (d__1 = dx[i], abs(d__1));
L30:
        ;
    }
    return ret_val;
} /* idamax_ */

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