コード例 #1
0
        private RouteFound AfterSelectt5(IProblem problem, RouteFound route, EdgeSet X, EdgeSet Y, EdgeList x, EdgeList y)
        {
            if (x.Count != y.Count)
            {
                OsmSharp.Tools.Output.OutputStreamHost.Write(string.Empty);
            }
            int t_1 = x[0].From;
            int t_2i_min_1 = y[y.Count - 1].To;

            // try and find a better route with t_1.
            RouteFound new_route = new RouteFound()
            {
                RouteWeight = float.MaxValue,
                Route = null
            };

            HashSet<int> exceptions = new HashSet<int>();
            int? result = this.SelectX(problem, route.Route, X, Y, x, t_2i_min_1, exceptions);
            while (result != null) // do backtacking over x: TODO: improve this and immidiately find the correct tour.
            {
                int t_2i = result.Value;
                exceptions.Add(t_2i);

                // step 6.
                t_2i = result.Value;
                Edge x_edge = new Edge()
                {
                    From = t_2i_min_1,
                    To = t_2i,
                    Weight = problem.Weight(t_2i_min_1, t_2i)
                };
                x.Add(x_edge);
                X.Add(x_edge);

                // Test the route T' for feasability and weight.
                y.Add(new Edge()
                {
                    From = t_2i,
                    To = t_1,
                    Weight = problem.Weight(t_2i, t_2i)
                });
                new_route.Route = this.Replace(route.Route, x, y);
                y.RemoveLast(); // remove the perliminary y.

                if (x.Count != y.Count + 1)
                {
                    OsmSharp.Tools.Output.OutputStreamHost.Write(string.Empty);
                }

                if (new_route.Route.IsValid())
                {
                    // stop the search for now if the route is already better.
                    new_route.RouteWeight = LinKernighanSolver.Weight(problem, new_route.Route);
                    if (new_route.RouteWeight < route.RouteWeight)
                    { // break.
                        Console.WriteLine("Route {0}:{1}",
                            new_route.Route.ToString(),
                            new_route.RouteWeight);
                        return new_route;
                    }

                    // choose next y.
                    result = this.SelectY(problem, route.Route, X, Y, x, y, null);
                    if (result != null)
                    {
                        int t_2_plus_1 = result.Value;
                        Edge y_edge = new Edge()
                        {
                            From = t_2i,
                            To = t_2_plus_1,
                            Weight = problem.Weight(t_2i, t_2_plus_1)
                        };
                        y.Add(y_edge);
                        Y.Add(y_edge);

                        // choose next.
                        new_route = this.AfterSelectt5(problem, route, X, Y, x, y);
                        if (new_route.RouteWeight < route.RouteWeight)
                        { // break.
                            Console.WriteLine("Route {0}:{1}",
                                new_route.Route.ToString(),
                                new_route.RouteWeight);
                            return new_route;
                        }

                        // remove y again.
                        y.RemoveLast();
                    }
                    x.RemoveLast();
                    break; // the other x cannot be valid!
                }

                // backtrack over x.
                x.RemoveLast();
                result = this.SelectX(problem, route.Route, X, Y, x, t_2i_min_1, exceptions);
            }
            if (x.Count != y.Count)
            {
                OsmSharp.Tools.Output.OutputStreamHost.Write(string.Empty);
            }
            return new_route;
        }
コード例 #2
0
        private RouteFound AfterSelectt4(IProblem problem, RouteFound route, EdgeSet X, EdgeSet Y, EdgeList x, EdgeList y)
        {
            int t_1 = x[0].From;
            int t_3 = y[0].To;
            int t_4 = x[1].To;

            // try and find a better route with t_1.
            RouteFound new_route = new RouteFound()
            {
                RouteWeight = float.MaxValue,
                Route = null
            };

            // choose t_5 for backtracking later.
            HashSet<int> t_5_exceptions = new HashSet<int>();
            int? result = this.SelectY(problem, route.Route, X, Y, x, y, t_5_exceptions);
            while (result != null)
            {
                // choose t_5.
                int t_5 = result.Value;
                t_5_exceptions.Add(t_5);
                Edge y_2 = new Edge()
                {
                    From = t_4,
                    To = t_5,
                    Weight = problem.Weight(t_4, t_5)
                };
                y.Add(y_2);
                Y.Add(y_2);

                if (x.Count != y.Count)
                {
                    OsmSharp.Tools.Output.OutputStreamHost.Write(string.Empty);
                }

                // try and find a better route by selecting more customer.
                new_route = this.AfterSelectt5(problem, route, X, Y, x, y);
                if (new_route.Route != null &&
                    new_route.RouteWeight < route.RouteWeight)
                { // trackback to t_1 if a better route is found.
                    break;
                }

                // remove and backtrack y_2.
                y.RemoveLast();

                if (x.Count != y.Count + 1)
                {
                    OsmSharp.Tools.Output.OutputStreamHost.Write(string.Empty);
                }

                result = this.SelectY(problem, route.Route, X, Y, x, y, t_5_exceptions);
            } // choose t_5
            return new_route;
        }
コード例 #3
0
        private RouteFound AfterSelectt2(IProblem problem, RouteFound route, EdgeSet X, EdgeSet Y, EdgeList x)
        {
            int t_2 = x[0].To;

            // try and find a better route with t_1.
            RouteFound new_route = new RouteFound()
            {
                RouteWeight = float.MaxValue,
                Route = null
            };

            // step 4 and step 10.
            HashSet<int> t_3_exceptions = new HashSet<int>();
            EdgeList y = new EdgeList();
            int? result = this.SelectY(problem, route.Route, X, Y, x, y, t_3_exceptions);
            while (result != null)
            {
                // select t_3.
                int t_3 = result.Value;
                t_3_exceptions.Add(t_3);

                // add y_1 to the edge list.
                Edge y_edge = new Edge()
                {
                    From = t_2,
                    To = t_3,
                    Weight = problem.Weight(t_2, t_3)
                };
                y.Add(y_edge);
                Y.Add(y_edge);

                // search route with t_3.
                new_route = this.AfterSelectt3(problem, route, X, Y, x, y);
                if (new_route.Route != null &&
                    new_route.RouteWeight < route.RouteWeight)
                { // trackback to t_1 if a better route is found.
                    break;
                }

                // remove y_1 again and backtrack.
                y.RemoveLast();

                if (x.Count != y.Count + 1)
                {
                    OsmSharp.Tools.Output.OutputStreamHost.Write(string.Empty);
                }

                result = this.SelectY(problem, route.Route, X, Y, x, y, t_3_exceptions);
            }
            return new_route;
        }
コード例 #4
0
        private RouteFound AfterSelectt3(IProblem problem, RouteFound route, EdgeSet X, EdgeSet Y, EdgeList x, EdgeList y)
        {
            int t_1 = x[0].From;
            int t_3 = y[0].To;

            // try and find a better route with t_1.
            RouteFound new_route = new RouteFound()
            {
                RouteWeight = float.MaxValue,
                Route = null
            };

            // choose t_4 for backtracking later.
            HashSet<int> t_4_exceptions = new HashSet<int>();
            int? result = this.SelectX(problem, route.Route, X, Y, x, t_3, t_4_exceptions);
            while (result != null)
            {
                // select t_4.
                int t_4 = result.Value;
                t_4_exceptions.Add(t_4);

                // add to x and test with perliminary y.
                Edge x_edge = new Edge()
                {
                    From = t_3,
                    To = t_4,
                    Weight = problem.Weight(t_3, t_4)
                };
                x.Add(x_edge);
                X.Add(x_edge);

                // Test the route T' for feasability and weight.
                y.Add(new Edge()
                {
                    From = t_4,
                    To = t_1,
                    Weight = problem.Weight(t_4, t_1)
                });
                new_route.Route = this.Replace(route.Route, x, y);
                y.RemoveLast(); // remove the perliminary y.
                if (new_route.Route.IsValid())
                {
                    // stop the search for now if the route is already better.
                    new_route.RouteWeight = LinKernighanSolver.Weight(problem, new_route.Route);
                    if (new_route.RouteWeight < route.RouteWeight)
                    { // break.
                        Console.WriteLine("Route {0}:{1}",
                            new_route.Route.ToString(),
                            new_route.RouteWeight);
                        x.RemoveLast(); // remove the latest x here!
                        break;
                    }
                }

                // choose t_5 here.
                new_route = this.AfterSelectt4(problem, route, X, Y, x, y);
                if (new_route.Route != null &&
                    new_route.RouteWeight < route.RouteWeight)
                { // trackback to t_1 if a better route is found.
                    break;
                }

                // reset the new route.
                new_route.Route = null;
                new_route.RouteWeight = float.MaxValue;

                // remove and backtrack x_2.
                x.RemoveLast();

                if (x.Count != y.Count)
                {
                    OsmSharp.Tools.Output.OutputStreamHost.Write(string.Empty);
                }

                result = this.SelectX(problem, route.Route, X, Y, x, t_3, t_4_exceptions);
            } // choose t_4
            return new_route;
        }
コード例 #5
0
        private RouteFound AfterSelectt1(IProblem problem, RouteFound route, EdgeSet X, EdgeSet Y, int t_1)
        {
            // try and find a better route with t_1.
            RouteFound new_route = new RouteFound()
            {
                RouteWeight = float.MaxValue,
                Route = null
            };

            // step 3 and step 11.
            HashSet<int> t_2_exceptions = new HashSet<int>();
            EdgeList x = new EdgeList();
            int? result = this.SelectX(problem, route.Route, X, Y, x, t_1, t_2_exceptions);
            while (result != null)
            {
                // select t_2.
                int t_2 = result.Value;
                t_2_exceptions.Add(t_2);

                // add x_1 to the edge list.
                Edge x_edge = new Edge()
                {
                    From = t_1,
                    To = t_2,
                    Weight = problem.Weight(t_1, t_2)
                };
                x.Add(x_edge);
                X.Add(x_edge);

                // search route with t_2.
                new_route = this.AfterSelectt2(problem, route, X, Y, x);
                if (new_route.Route != null &&
                    new_route.RouteWeight < route.RouteWeight)
                { // trackback to t_1 if a better route is found.
                    break;
                }

                // remove x_1 again and backtrack.
                x.RemoveLast();

                result = this.SelectX(problem, route.Route, X, Y, x, t_1, t_2_exceptions);
            } // step 3 and step 11.
            return new_route;
        }