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/* The C clustering library.
 * Copyright (C) 2002 Michiel Jan Laurens de Hoon.
 *
 * This library was written at the Laboratory of DNA Information Analysis,
 * Human Genome Center, Institute of Medical Science, University of Tokyo,
 * 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
 * Contact: michiel.dehoon 'AT' riken.jp
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation with or without modifications and for any purpose and
 * without fee is hereby granted, provided that any copyright notices
 * appear in all copies and that both those copyright notices and this
 * permission notice appear in supporting documentation, and that the
 * names of the contributors or copyright holders not be used in
 * advertising or publicity pertaining to distribution of the software
 * without specific prior permission.
 *
 * THE CONTRIBUTORS AND COPYRIGHT HOLDERS OF THIS SOFTWARE DISCLAIM ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE
 * CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT
 * OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE
 * OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include <time.h>
#include <stdlib.h>
#include <math.h>
#include <float.h>
#include <limits.h>
#include <string.h>
#include "cluster.h"

/* ************************************************************************ */

double
mean(int n, double x[])
{
    double result = 0.;
    int i;

    for (i = 0; i < n; i++) result += x[i];
    result /= n;
    return result;
}

/* ************************************************************************ */

double
median(int n, double x[])
/*
Find the median of X(1), ... , X(N), using as much of the quicksort
algorithm as is needed to isolate it.
N.B. On exit, the array X is partially ordered.
Based on Alan J. Miller's median.f90 routine.
*/

{
    int i, j;
    int nr = n / 2;
    int nl = nr - 1;
    int even = 0;
    /* hi & lo are position limits encompassing the median. */
    int lo = 0;
    int hi = n-1;

    if (n == 2*nr) even = 1;
    if (n < 3) {
        if (n < 1) return 0.;
        if (n == 1) return x[0];
        return 0.5*(x[0]+x[1]);
    }

    /* Find median of 1st, middle & last values. */
    do {
        int loop;
        int mid = (lo + hi)/2;
        double result = x[mid];
        double xlo = x[lo];
        double xhi = x[hi];