/* * KnuthSubtractive.java * * Created on January 17, 2003, 12:33 AM * *  * Copyright (C) 2003 - Edwin S. Peer * * 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 2 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, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA  *   * This code is based on the implementation in GSL (GNU Scientific Library)  * which is also covered by the GNU General Public License. The original C  * source code is Copyright (C) 1996, 1997, 1998, 1999, 2000 James Theiler  * and Brian Gough. *  */package net.sourceforge.cilib.Random;import java.util.*;/** * * @author  espeer */public class KnuthSubtractive extends Random {        public KnuthSubtractive() {        super();    }        public KnuthSubtractive(long seed) {        super(seed);    }        public void setSeed(long seed) {        buffer = new long[56];                if (seed == 0) {            seed = 1;        }                long j = (M_SEED - seed) % M_BIG;                buffer[0] = 0;        buffer[55] = j;                long k = 1;        for (int i = 1; i < 55; ++i) {            int n = (21 * i) % 55;            buffer[n] = k;            k = j - k;            if (k < 0) {                k += M_BIG;            }            j = buffer[n];        }                for (int i1 = 0; i1 < 4; ++i1) {            for (int i = 1; i < 56; ++i) {                long t = buffer[i] - buffer[1 + (i + 30) % 55];                if (t < 0) {                    t += M_BIG;                }                buffer[i] = t;            }        }                x = 0;        y = 31;    }        protected int next(int bits) {        ++x;        if (x == 56) {            x = 1;        }        ++y;        if (y == 56) {            y = 1;        }                long j = buffer[x] - buffer[y];        if (j < 0) {            j += M_BIG;        }        buffer[x] = j;                return (int) ((j & 0xffffffffL) >>> (32 - bits));     }        private static final long M_BIG = 0xffffffffL;    private static final long M_SEED = 161803398;        private int x;    private int y;    private long[] buffer;    }