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MagicSquare.java

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/* -*- indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Mikael Lagerkvist <lagerkvist@gecode.org>
 *     Guido Tack <tack@gecode.org>
 *
 *  Copyright:
 *     Mikael Lagerkvist, 2006
 *     Guido Tack, 2006
 *
 *  Last modified:
 *     $Date: 2007-12-05 14:47:42 +0100 (Wed, 05 Dec 2007) $ by $Author: zayenz $
 *     $Revision: 5594 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  Permission is hereby granted, free of charge, to any person obtaining
 *  a copy of this software and associated documentation files (the
 *  "Software"), to deal in the Software without restriction, including
 *  without limitation the rights to use, copy, modify, merge, publish,
 *  distribute, sublicense, and/or sell copies of the Software, and to
 *  permit persons to whom the Software is furnished to do so, subject to
 *  the following conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

package examples;

import static org.gecode.Gecode.*;
import static org.gecode.GecodeEnumConstants.*;

import org.gecode.*;

public class MagicSquare extends Space {
  private int n;
  private VarMatrix<IntVar> m;

  public MagicSquare(int size) {
    super("MagicSquare");
    n = size;
    final int 
      nn = n*n,
      s = nn*(nn+1) / (2*n);
    m = new VarMatrix<IntVar>(this, n, n, IntVar.class, 1, nn);
        
    // Rows and columns
    for (int i = n; i-- != 0; ) {
      linear(this, m.row(i), IRT_EQ, s);
      linear(this, m.col(i), IRT_EQ, s);
    }
    // Diagonals
    {
      VarArray<IntVar> d1 = new VarArray<IntVar>(n);
      VarArray<IntVar> d2 = new VarArray<IntVar>(n);
      for (int i = 0; i<n; ++i) {
        d1.add(i, m.get(i,i));
        d2.add(i, m.get(n-i-1, i));
      }
      linear(this, d1, IRT_EQ, s);
      linear(this, d2, IRT_EQ, s);
    }

    // All fields must be distinct
    distinct(this, m, ICL_DEF);

    // Break some (few) symmetries
    rel(this, m.get(0,0), IRT_GR, m.get(0,n-1));
    rel(this, m.get(0,0), IRT_GR, m.get(n-1,0));

    branch(this, m, INT_VAR_SIZE_MIN, INT_VAL_SPLIT_MIN);
  }

  public MagicSquare(Boolean share, MagicSquare msq) {
    super(share, msq);
    n = msq.n;
    m = new VarMatrix<IntVar>(this, share, msq.m);
  }

  public String toString() {
    String res = "";
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < n; ++j) {
        if (m.get(i,j).max() < 10) res += " ";
        res += m.get(i,j).toString();
        res += " ";
      }
      res += '\n';
    }
    return res;
  }

  public void print() {
    System.out.println("Solution:");

    System.out.println(toString());
  }

  public static void main(String []args) {
    Options opt = new Options("MagicSquare");
    opt.size = 6;
    opt.gui = true;
    opt.parse(args);

    MagicSquare ms = new MagicSquare(opt.size);
    opt.doSearch(ms);
  }
}