content: package kodkod.examples.csp;
  
  import java.util.ArrayList;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import kodkod.ast.Formula;
  import kodkod.ast.Relation;
  import kodkod.engine.Solution;
  import kodkod.engine.Solver;
  import kodkod.engine.config.ConsoleReporter;
  import kodkod.engine.satlab.SATFactory;
  import kodkod.instance.Bounds;
  import kodkod.instance.TupleSet;
  import kodkod.instance.Universe;
  
  
  public class GraphColoring2  {
  	private final Relation[] vcolors;
  	private final int[][] graph;
  	private final Bounds bounds;
  	/**
  	 * Constructs an instance of the graph coloring problem for the given graph and the number of colors.
  	 * @requires colors > 0
  	 */
  	public GraphColoring2(String file, Graph.Format format, int colors) {
  		assert colors > 0;
  		final Graph<?> g =   format.parse(file);
  		final int vertices = g.nodes().size();
  		vcolors = new Relation[vertices];   
  		for(int i = 0; i < vertices; i++) { 
  			vcolors[i] = Relation.unary("v"+i+"color");
  		}
  		final List<Object> atoms = new ArrayList<Object>(colors);
  		for(int i = 0 ; i < colors; i++) { atoms.add(new Color(i)); }
  		final Universe u = new Universe(atoms);
  		bounds = new Bounds(u);
  		final TupleSet all = u.factory().allOf(1);
  		for(Relation r : vcolors) { 
  			bounds.bound(r, all);
  		}
  		graph = new int[vertices][];
  		final Map<Object,Integer> ids = new LinkedHashMap<Object, Integer>();
  		int i = 0;
  		for(Object n : g.nodes()) { 
  			ids.put(n, i++);
  		}
  		i = 0;
  		for(Object n : g.nodes()) { 
  			final Set<?> neighbors = g.edges(n);
  			graph[i] = new int[neighbors.size()];
  			int j = 0;
  			for(Object neighbor : neighbors) { 
  				graph[i][j++] = ids.get(neighbor);
  			}
  			i++;
  		}
  		
  	}
  	
  	private static final class Color {
  		final int value;
  		Color(int value) { this.value = value; }
  		public String toString() { return "color"+value; }
  	}
  	
  	/**
  	 * Returns a formula stating that all vertices
  	 * have  one color, and that no two adjacent
  	 * vertices have intersecting colors.
  	 * @return a formula stating that all vertices
  	 * have one color, and that no two adjacent
  	 * vertices have intersecting colors.
  	 */
  	public Formula coloring() {
  		final List<Formula> formulas = new ArrayList<Formula>(vcolors.length);
  		for(Relation r : vcolors) { 
  			formulas.add( r.one() );
  		}
  		for(int i = 0; i < vcolors.length; i++) { 
  			final int[] neighbors = graph[i];
  			final int max = neighbors.length;
  			final Relation vcolor = vcolors[i];
  			for(int j = 0; j < max; j++) { 
  				formulas.add( vcolor.intersection(vcolors[neighbors[j]]).no() );
  			}
  		}
  		return Formula.and(formulas);
  	}
  	
  	/**
  	 * Returns the bounds for this coloring problem.
  	 * @return bounds for this coloring problem
  	 */
  	public Bounds bounds() { 
  		return bounds.unmodifiableView();
  	}
  	
  	private static void usage() { 
  		System.out.println("Usage: java examples.classicnp.GraphColoring <filename> <DIMACS | ASP | ASP_EDGES> <# of colors>");
  		System.exit(1);
  	}
  	
  	/**
  	 * Usage: java examples.classicnp.GraphColoring <filename> <DIMACS | ASP | ASP_EDGES> <# of colors>
  	 */
  	public static void main(String[] args) {
  		if (args.length!=3) usage();
  		
  		try {
  			final GraphColoring2 model = new GraphColoring2(args[0], Enum.valueOf(Graph.Format.class, args[1].toUpperCase()), Integer.parseInt(args[2]));
  			final Solver solver = new Solver();
  			solver.options().setSolver(SATFactory.DEFAULT);
  			solver.options().setSymmetryBreaking(0);
  			solver.options().setReporter(new ConsoleReporter());
  			final Formula f = model.coloring();
  			final Bounds b = model.bounds();
  			final Solution sol = solver.solve(f, b);
  			System.out.println(sol.outcome());
  			System.out.println(sol.stats());
  			//if (sol.instance()!=null)
  			//	System.out.println("coloring: "+sol.instance().tuples(model.v2c));
  
  		} catch (NumberFormatException e) { usage(); }
  	}
  }
  
  