Utilidades.java

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

	This file is part of KEEL-software, the Data Mining tool for regression, 
	classification, clustering, pattern mining and so on.

	Copyright (C) 2004-2010

	F. Herrera (herrera@decsai.ugr.es)
    L. S�nchez (luciano@uniovi.es)
    J. Alcal�-Fdez (jalcala@decsai.ugr.es)
    S. Garc�a (sglopez@ujaen.es)
    A. Fern�ndez (alberto.fernandez@ujaen.es)
    J. Luengo (julianlm@decsai.ugr.es)

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see http://www.gnu.org/licenses/

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

package keel.Algorithms.Semi_Supervised_Learning.Basic;


import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;



import keel.Algorithms.Semi_Supervised_Learning.Basic.*;

public class Utilidades {
		
	public static void quicksort(double[] main, int[] index) {
	    quicksort(main, index, 0, index.length - 1);
	}

	// quicksort a[left] to a[right]
	public static void quicksort(double[] a, int[] index, int left, int right) {
	    if (right <= left) return;
	    int i = partition(a, index, left, right);
	    quicksort(a, index, left, i-1);
	    quicksort(a, index, i+1, right);
	}

	// partition a[left] to a[right], assumes left < right
	private static int partition(double[] a, int[] index, int left, int right) {
	    int i = left - 1;
	    int j = right;
	    while (true) {
		while (less(a[++i], a[right]))      // find item on left to swap
		    ;                               // a[right] acts as sentinel
		while (less(a[right], a[--j]))      // find item on right to swap
		    if (j == left) break;           // don't go out-of-bounds
		if (i >= j) break;                  // check if pointers cross
		exch(a, index, i, j);               // swap two elements into place
	    }
	    exch(a, index, i, right);               // swap with partition element
	    return i;
	}

	// is x < y ?
	private static boolean less(double x, double y) {
	    return (x < y);
	}

	// exchange a[i] and a[j]
	private static void exch(double[] a, int[] index, int i, int j) {
	    double swap = a[i];
	    a[i] = a[j];
	    a[j] = swap;
	    int b = index[i];
	    index[i] = index[j];
	    index[j] = b;
	}

	
	
}