Exemple #1
0
        /// <summary>
        /// Tests all enumerations of a route.
        /// </summary>
        protected void DoTestEnumerateBetween()
        {
            int count = 10;

            IRoute route = this.BuildRoute(true);

            if (route != null)
            { // this part needs testing.
                for (int customer = 0; customer < count; customer++)
                {
                    route.InsertAfter(customer - 1, customer);
                    //route.InsertAfterAndRemove(customer - 1, customer, -1);
                }
            }

            for (int from = 0; from < count; from++)
            {
                for (int to = 0; to < count; to++)
                {
                    IEnumerator <int> enumerator = route.Between(from, to).GetEnumerator();
                    for (int customer = from; customer - 1 != to; customer++)
                    {
                        if (customer == count)
                        {
                            customer = 0;
                        }

                        Assert.IsTrue(enumerator.MoveNext());
                        Assert.AreEqual(customer, enumerator.Current);
                    }
                }
            }
        }
Exemple #2
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        /// <summary>
        /// Tries all 3Opt Moves for the neighbourhood of v_1.
        /// </summary>
        /// <param name="problem"></param>
        /// <param name="weights"></param>
        /// <param name="route"></param>
        /// <param name="v1"></param>
        /// <returns></returns>
        public bool Try3OptMoves(IProblemWeights problem, double[][] weights, IRoute route, int v1)
        {
            // get v_2.
            int v_2 = route.GetNeigbours(v1)[0];

            if (v_2 < 0)
            {
                return(false);
            }
            IEnumerable <int> between_v_2_v_1 = route.Between(v_2, v1);
            double            weight_1_2      = weights[v1][v_2];
            int v_3 = -1;
            NearestNeighbours10 neighbours = null;

            if (_nearest_neighbours)
            {
                neighbours = problem.Get10NearestNeighbours(v1);
            }

            foreach (int v_4 in between_v_2_v_1)
            {
                if (v_3 >= 0 && v_3 != v1)
                {
                    //if (!_nearest_neighbours ||
                    //    neighbours.Max <= weight_1_4)
                    if (!_nearest_neighbours ||
                        neighbours.Contains(v_4))
                    {
                        double   weight_1_4          = weights[v1][v_4];
                        double   weight_1_2_plus_3_4 = weight_1_2 + weights[v_3][v_4];
                        double[] weights_3           = weights[v_3];
                        if (this.Try3OptMoves(problem, weights, route, v1, v_2, v_3, weights_3, v_4, weight_1_2_plus_3_4, weight_1_4))
                        {
                            return(true);
                        }
                    }
                }
                v_3 = v_4;
            }
            return(false);
        }
Exemple #3
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        /// <summary>
        /// Applies inter-improvements by exchanging parts of the route(s).
        /// </summary>
        /// <param name="problem"></param>
        /// <param name="solution"></param>
        /// <param name="route1_idx"></param>
        /// <param name="route2_idx"></param>
        /// <param name="max"></param>
        /// <returns></returns>
        public bool Improve(MaxTimeProblem problem, MaxTimeSolution solution,
                            int route1_idx, int route2_idx, double max)
        {
            int max_window = 40;

            IRoute route1 = solution.Route(route1_idx);
            IRoute route2 = solution.Route(route2_idx);

            int route1_customers = route1.Count;
            int route2_customers = route2.Count;

            double[] route1_cumul = problem.TimeCumul(route1);
            double[] route2_cumul = problem.TimeCumul(route2);

            // build all edge weights.
            List <Edge> route1_edges = new List <Edge>(route1.Edges());
            List <Edge> route2_edges = new List <Edge>(route2.Edges());

            double[] route1_weights = new double[route1_edges.Count];
            for (int idx = 0; idx < route1_edges.Count; idx++)
            {
                Edge edge = route1_edges[idx];
                route1_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
            }
            double[] route2_weights = new double[route2_edges.Count];
            for (int idx = 0; idx < route2_edges.Count; idx++)
            {
                Edge edge = route2_edges[idx];
                route2_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
            }

            List <EdgePair> route2_pairs = new List <EdgePair>();

            for (int i_idx = 0; i_idx < route2_edges.Count - 2; i_idx++)
            {
                Edge   i               = route2_edges[i_idx];
                double i_weight        = route2_weights[i_idx];
                double weight_before_i = route2_cumul[i_idx];

                int k_idx_max = route2_edges.Count;
                if (k_idx_max > i_idx + 2 + max_window)
                {
                    k_idx_max = i_idx + 2 + max_window;
                }
                for (int k_idx = i_idx + 2; k_idx < k_idx_max; k_idx++)
                {
                    Edge   k                    = route2_edges[k_idx];
                    double k_weight             = route2_weights[k_idx];
                    double weight_after_k       = route2_cumul[route2_cumul.Length - 1] - route2_cumul[k_idx + 1];
                    double weight_between_route = route2_cumul[k_idx] - route2_cumul[i_idx + 1];

                    route2_pairs.Add(new EdgePair()
                    {
                        First            = i,
                        FirstWeight      = i_weight,
                        Second           = k,
                        SecondWeight     = k_weight,
                        Between          = new List <int>(route2.Between(i.To, k.From)),
                        WeightTotal      = i_weight + k_weight,
                        WeightAfter      = weight_after_k,
                        WeightBefore     = weight_before_i,
                        WeightBetween    = weight_between_route,
                        CustomersBetween = k_idx - i_idx
                    });
                }
            }

            // build all edge pairs.
            for (int i_idx = 0; i_idx < route1_edges.Count - 2; i_idx++)
            {
                Edge   i               = route1_edges[i_idx];
                double i_weight        = route1_weights[i_idx];
                double weight_before_i = route1_cumul[i_idx];

                int k_idx_max = route1_edges.Count;
                if (k_idx_max > i_idx + 2 + max_window)
                {
                    k_idx_max = i_idx + 2 + max_window;
                }
                for (int k_idx = i_idx + 2; k_idx < k_idx_max; k_idx++)
                {
                    Edge   k                    = route1_edges[k_idx];
                    double k_weight             = route1_weights[k_idx];
                    double weight_after_k       = route1_cumul[route1_cumul.Length - 1] - route1_cumul[k_idx + 1];
                    double weight_between_route = route1_cumul[k_idx] - route1_cumul[i_idx + 1];

                    EdgePair pair1 = new EdgePair()
                    {
                        First            = i,
                        FirstWeight      = i_weight,
                        Second           = k,
                        SecondWeight     = k_weight,
                        Between          = new List <int>(route1.Between(i.To, k.From)),
                        WeightTotal      = i_weight + k_weight,
                        WeightAfter      = weight_after_k,
                        WeightBefore     = weight_before_i,
                        WeightBetween    = weight_between_route,
                        CustomersBetween = k_idx - i_idx
                    };

                    foreach (EdgePair pair2 in route2_pairs)
                    {
                        double existing_weight = pair1.WeightTotal + pair2.WeightTotal;

                        //double new_weight = 0;

                        // get first route new.
                        double new_weight = problem.WeightMatrix[pair1.First.From][pair2.First.To];
                        //new_weight = first_route1_new;
                        if (new_weight > existing_weight - 0.001)
                        {
                            continue;
                        }

                        double first_route2_new = problem.WeightMatrix[pair2.First.From][pair1.First.To];
                        new_weight = new_weight + first_route2_new;
                        if (new_weight > existing_weight - 0.001)
                        {
                            continue;
                        }

                        double second_route1_new = problem.WeightMatrix[pair1.Second.From][pair2.Second.To];
                        new_weight = new_weight + second_route1_new;
                        if (new_weight > existing_weight - 0.001)
                        {
                            continue;
                        }

                        double second_route2_new = problem.WeightMatrix[pair2.Second.From][pair1.Second.To];
                        new_weight = new_weight + second_route2_new;

                        if (new_weight < existing_weight - 0.001)
                        { // there is a decrease in total weight; check bounds.
                            double route1_weight = pair1.WeightBefore + pair2.WeightBetween + pair1.WeightAfter;
                            double route2_weight = pair2.WeightBefore + pair1.WeightBetween + pair2.WeightAfter;

                            // calculate the maximum.
                            int route1_customers_between = pair1.CustomersBetween;
                            int route2_customers_between = pair1.CustomersBetween;
                            route1_weight = problem.Time(route1_weight,
                                                         route1_customers - route1_customers_between + route2_customers_between);
                            route2_weight = problem.Time(route2_weight,
                                                         route2_customers - route2_customers_between + route1_customers_between);

                            if (route1_weight < max && route2_weight < max)
                            {
                                MaxTimeSolution solution_copy = solution.Clone() as MaxTimeSolution;

                                List <int> route1_between = pair1.Between;
                                List <int> route2_between = pair2.Between;

                                route1.ReplaceEdgeFrom(pair1.First.From, pair1.Second.To);
                                route2.ReplaceEdgeFrom(pair2.First.From, pair2.Second.To);

                                int previous = pair1.First.From;
                                for (int idx = 0; idx < route2_between.Count; idx++)
                                {
                                    route1.ReplaceEdgeFrom(previous, route2_between[idx]);
                                    previous = route2_between[idx];
                                }
                                route1.ReplaceEdgeFrom(previous, pair1.Second.To);

                                previous = pair2.First.From;
                                for (int idx = 0; idx < route1_between.Count; idx++)
                                {
                                    route2.ReplaceEdgeFrom(previous, route1_between[idx]);
                                    previous = route1_between[idx];
                                }
                                route2.ReplaceEdgeFrom(previous, pair2.Second.To);

                                if (!solution.IsValid())
                                {
                                    throw new Exception();
                                }
                                return(true);
                            }
                        }
                    }
                }
            }
            return(false);
        }
Exemple #4
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        /// <summary>
        /// Tries all 3Opt Moves for the neighbourhood of v_1 containing v_3.
        /// </summary>
        /// <param name="problem"></param>
        /// <param name="weights"></param>
        /// <param name="route"></param>
        /// <param name="v1"></param>
        /// <param name="v_2"></param>
        /// <param name="v_3"></param>
        /// <param name="weights_3"></param>
        /// <param name="v_4"></param>
        /// <param name="weight_1_2_plus_3_4"></param>
        /// <param name="weight_1_4"></param>
        /// <returns></returns>
        public bool Try3OptMoves(IProblemWeights problem, double[][] weights, IRoute route,
                                 int v1, int v_2, int v_3, double[] weights_3, int v_4, double weight_1_2_plus_3_4, double weight_1_4)
        {
            //IEnumerable<int> between_v_4_v_1 = route.Between(v_4, v_1);
            //foreach (int v_5 in between_v_4_v_1)
            //{
            //    if (v_5 != v_1)
            //    {
            //        if (this.Try3OptMove(problem, weights, route, v_1, v_2, v_3, weights_3, v_4, weight_1_2_plus_3_4, weight_1_4, v_5))
            //        {
            //            return true;
            //        }
            //    }
            //}
            //return false;

            IEnumerator <int> between_v_4_v_1_enumerator = route.Between(v_4, v1).GetEnumerator();

            if (between_v_4_v_1_enumerator.MoveNext())
            {
                int v_5 = between_v_4_v_1_enumerator.Current;
                if (v_5 != v1)
                {
                    while (between_v_4_v_1_enumerator.MoveNext())
                    {
                        int v_6 = between_v_4_v_1_enumerator.Current;
                        //Console.WriteLine(v_6);
                        //if (this.Try3OptMove(problem, weights,
                        //    route, v_1, v_2, v_3, weights_3, v_4,
                        //    weight_1_2_plus_3_4, weight_1_4, v_5, v_6))
                        //{
                        // calculate the total weight of the 'new' arcs.
                        double weight_new = weight_1_4 +
                                            weights_3[v_6] +
                                            weights[v_5][v_2];

                        // calculate the total weights.
                        double weight = weight_1_2_plus_3_4 + weights[v_5][v_6];

                        if (weight - weight_new > _epsilon)
                        { // actually do replace the vertices.
                            int count_before = route.Count;
                            //string route_string = route.ToString();

                            route.ReplaceEdgeFrom(v1, v_4);
                            route.ReplaceEdgeFrom(v_3, v_6);
                            route.ReplaceEdgeFrom(v_5, v_2);

                            int count_after = route.Count;

                            if (count_before != count_after)
                            {
                                throw new Exception();
                            }
                            // set bits.
                            //this.Set(problem, v_1, false);
                            this.Set(problem, v_3, false);
                            this.Set(problem, v_5, false);

                            if (!route.IsValid())
                            {
                                throw new Exception();
                            }

                            return(true); // move succeeded.
                        }
                        //}
                        v_5 = v_6;
                    }
                }
            }
            return(false);
        }
Exemple #5
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        /// <summary>
        /// Tries to relocate customers using the source the same as the CrossExchange but places customers using cheapest insertion.
        /// </summary>
        /// <param name="problem"></param>
        /// <param name="solution"></param>
        /// <param name="route1_idx"></param>
        /// <param name="route2_idx"></param>
        /// <param name="max"></param>
        /// <returns></returns>
        public bool Improve(MaxTimeProblem problem, MaxTimeSolution solution,
                            int route1_idx, int route2_idx, double max)
        {
            int max_window = 10;

            IRoute route1 = solution.Route(route1_idx);
            IRoute route2 = solution.Route(route2_idx);

            double total_before = problem.Time(solution.Route(route1_idx)) +
                                  problem.Time(solution.Route(route2_idx));

            int route1_customers = route1.Count;
            int route2_customers = route2.Count;

            double[] route1_cumul = problem.TimeCumul(route1);
            double[] route2_cumul = problem.TimeCumul(route2);

            // build all edge weights.
            List <Edge> route1_edges = new List <Edge>(route1.Edges());
            List <Edge> route2_edges = new List <Edge>(route2.Edges());

            double[] route1_weights = new double[route1_edges.Count];
            for (int idx = 0; idx < route1_edges.Count; idx++)
            {
                Edge edge = route1_edges[idx];
                route1_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
            }
            double[] route2_weights = new double[route2_edges.Count];
            for (int idx = 0; idx < route2_edges.Count; idx++)
            {
                Edge edge = route2_edges[idx];
                route2_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
            }

            List <EdgePair> route2_pairs = new List <EdgePair>();

            for (int i_idx = 0; i_idx < route2_edges.Count - 2; i_idx++)
            {
                Edge   i               = route2_edges[i_idx];
                double i_weight        = route2_weights[i_idx];
                double weight_before_i = route2_cumul[i_idx];

                int k_idx_max = route2_edges.Count;
                if (k_idx_max > i_idx + 2 + max_window)
                {
                    k_idx_max = i_idx + 2 + max_window;
                }
                for (int k_idx = i_idx + 2; k_idx < k_idx_max; k_idx++)
                {
                    Edge   k                    = route2_edges[k_idx];
                    double k_weight             = route2_weights[k_idx];
                    double weight_after_k       = route2_cumul[route2_cumul.Length - 1] - route2_cumul[k_idx + 1];
                    double weight_between_route = route2_cumul[k_idx] - route2_cumul[i_idx + 1];

                    route2_pairs.Add(new EdgePair()
                    {
                        First            = i,
                        FirstWeight      = i_weight,
                        Second           = k,
                        SecondWeight     = k_weight,
                        Between          = new List <int>(route2.Between(i.To, k.From)),
                        WeightTotal      = i_weight + k_weight,
                        WeightAfter      = weight_after_k,
                        WeightBefore     = weight_before_i,
                        WeightBetween    = weight_between_route,
                        CustomersBetween = k_idx - i_idx
                    });
                }
            }

            // try to relocate all and find best pair.
            double   route1_weight = route1_cumul[route1_cumul.Length - 1];
            EdgePair best          = null;
            CheapestInsertionResult best_result = new CheapestInsertionResult();
            double best_extra = double.MaxValue;

            foreach (EdgePair pair2 in route2_pairs)
            {
                // calculate cheapest insertion.
                CheapestInsertionResult result =
                    CheapestInsertionHelper.CalculateBestPlacement(problem, route1,
                                                                   pair2.First.To, pair2.Second.From);

                double extra_route2 = problem.WeightMatrix[pair2.First.From][pair2.Second.To];

                // check if the result has a net-decrease.
                if (result.Increase + extra_route2 < pair2.WeightTotal - 0.01)
                { // there is a net decrease.
                    // calculate the real increase.
                    double new_weight = problem.Time(route1_weight + result.Increase + pair2.WeightBetween, route1_customers +
                                                     pair2.CustomersBetween);

                    // check the max.
                    if (new_weight < max && new_weight < best_extra)
                    { // the route is smaller than max.
                        best_extra  = new_weight;
                        best_result = result;
                        best        = pair2;
                    }
                }
            }

            if (best != null)
            {
                if (route2.Last == best.Second.To)
                {
                    //throw new Exception();
                }
                route2.ReplaceEdgeFrom(best.First.From, best.Second.To);

                int previous = best_result.CustomerBefore;
                foreach (int customer in best.Between)
                {
                    route1.ReplaceEdgeFrom(previous, customer);

                    previous = customer;
                }
                route1.ReplaceEdgeFrom(previous, best_result.CustomerAfter);

                // check validity.
                if (!route2.IsValid())
                {
                    throw new Exception();
                }
                if (!route1.IsValid())
                {
                    throw new Exception();
                }

                if (route1.Count + route2.Count != route1_customers + route2_customers)
                {
                    throw new Exception();
                }

                double total_after = problem.Time(solution.Route(route1_idx)) +
                                     problem.Time(solution.Route(route2_idx));
                if (total_after >= total_before)
                {
                    throw new Exception("this is not an improvement!");
                }

                return(true);
            }
            return(false);
        }
        /// <summary>
        /// Tries all 3Opt Moves for the neighbourhood of v_1 containing v_3.
        /// </summary>
        /// <param name="problem"></param>
        /// <param name="weights"></param>
        /// <param name="route"></param>
        /// <param name="v1"></param>
        /// <param name="v_2"></param>
        /// <param name="v_3"></param>
        /// <param name="weights_3"></param>
        /// <param name="v_4"></param>
        /// <param name="weight_1_2_plus_3_4"></param>
        /// <param name="weight_1_4"></param>
        /// <returns></returns>
        public bool Try3OptMoves(IProblemWeights problem, double[][] weights, IRoute route,
            int v1, int v_2, int v_3, double[] weights_3, int v_4, double weight_1_2_plus_3_4, double weight_1_4)
        {
            //IEnumerable<int> between_v_4_v_1 = route.Between(v_4, v_1);
            //foreach (int v_5 in between_v_4_v_1)
            //{
            //    if (v_5 != v_1)
            //    {
            //        if (this.Try3OptMove(problem, weights, route, v_1, v_2, v_3, weights_3, v_4, weight_1_2_plus_3_4, weight_1_4, v_5))
            //        {
            //            return true;
            //        }
            //    }
            //}
            //return false;

            IEnumerator<int> between_v_4_v_1_enumerator = route.Between(v_4, v1).GetEnumerator();
            if (between_v_4_v_1_enumerator.MoveNext())
            {
                int v_5 = between_v_4_v_1_enumerator.Current;
                if (v_5 != v1)
                {
                    while (between_v_4_v_1_enumerator.MoveNext())
                    {
                        int v_6 = between_v_4_v_1_enumerator.Current;
                        //Console.WriteLine(v_6);
                        //if (this.Try3OptMove(problem, weights,
                        //    route, v_1, v_2, v_3, weights_3, v_4,
                        //    weight_1_2_plus_3_4, weight_1_4, v_5, v_6))
                        //{
                        // calculate the total weight of the 'new' arcs.
                        double weight_new = weight_1_4 +
                            weights_3[v_6] +
                            weights[v_5][v_2];

                        // calculate the total weights.
                        double weight = weight_1_2_plus_3_4 + weights[v_5][v_6];

                        if (weight - weight_new > _epsilon)
                        { // actually do replace the vertices.
                            int count_before = route.Count;
                            //string route_string = route.ToString();

                            route.ReplaceEdgeFrom(v1, v_4);
                            route.ReplaceEdgeFrom(v_3, v_6);
                            route.ReplaceEdgeFrom(v_5, v_2);

                            int count_after = route.Count;

                            if (count_before != count_after)
                            {
                                throw new Exception();
                            }
                            // set bits.
                            //this.Set(problem, v_1, false);
                            this.Set(problem, v_3, false);
                            this.Set(problem, v_5, false);

                            if (!route.IsValid())
                            {
                                throw new Exception();
                            }

                            return true; // move succeeded.
                        }
                        //}
                        v_5 = v_6;
                    }
                }
            }
            return false;
        }
        /// <summary>
        /// Tries all 3Opt Moves for the neighbourhood of v_1.
        /// </summary>
        /// <param name="problem"></param>
        /// <param name="weights"></param>
        /// <param name="route"></param>
        /// <param name="v1"></param>
        /// <returns></returns>
        public bool Try3OptMoves(IProblemWeights problem, double[][] weights, IRoute route, int v1)
        {
            // get v_2.
            int v_2 = route.GetNeigbours(v1)[0];
            if (v_2 < 0)
            {
                return false;
            }
            IEnumerable<int> between_v_2_v_1 = route.Between(v_2, v1);
            double weight_1_2 = weights[v1][v_2];
            int v_3 = -1;
            NearestNeighbours10 neighbours = null;
            if (_nearest_neighbours)
            {
                neighbours = problem.Get10NearestNeighbours(v1);
            }

            foreach (int v_4 in between_v_2_v_1)
            {
                if (v_3 >= 0 && v_3 != v1)
                {
                    //if (!_nearest_neighbours ||
                    //    neighbours.Max <= weight_1_4)
                    if (!_nearest_neighbours ||
                        neighbours.Contains(v_4))
                    {
                        double weight_1_4 = weights[v1][v_4];
                        double weight_1_2_plus_3_4 = weight_1_2 + weights[v_3][v_4];
                        double[] weights_3 = weights[v_3];
                        if (this.Try3OptMoves(problem, weights, route, v1, v_2, v_3, weights_3, v_4, weight_1_2_plus_3_4, weight_1_4))
                        {
                            return true;
                        }
                    }
                }
                v_3 = v_4;
            }
            return false;
        }
Exemple #8
0
        /// <summary>
        /// Calculates a solution.
        /// </summary>
        /// <param name="problem"></param>
        /// <returns></returns>
        internal override MaxTimeSolution Solve(MaxTimeProblem problem)
        {
            // create the calculator.
            MaxTimeCalculator calculator = new MaxTimeCalculator(problem);

            // create the solution.
            MaxTimeSolution solution = new MaxTimeSolution(problem.Size, true);

            double max = problem.Max.Value;

            // keep placing customer until none are left.
            List <int> customers = new List <int>(problem.Customers);

            // create n routes.
            for (int customer = 0; customer < customers.Count; customer++)
            {
                solution.Add(customer);
                solution[solution.Count - 1] = calculator.CalculateOneRouteIncrease(
                    0, 0);
            }

            // creates a result.
            MergeResult result = new MergeResult();

            result.Weight = double.MaxValue;

            // loop over all route pairs and merge the smallest merge.
            while (result != null)
            { // keep looping until there is no result anymore.
                result        = new MergeResult();
                result.Weight = double.MaxValue;

                for (int route1_idx = 1; route1_idx < solution.Count; route1_idx++)
                {         // keep looping over all routes.
                    for (int route2_idx = 0; route2_idx < solution.Count; route2_idx++)
                    {     // keep looping over all routes.
                        if (route1_idx == route2_idx)
                        { // only consider different routes.
                            break;
                        }

                        // calculate the merge result.
                        MergeResult current_result = this.TryMerge(problem, solution,
                                                                   route1_idx, route2_idx, problem.Max.Value);

                        // evaluate the current result.
                        if (current_result != null && current_result.Weight < result.Weight)
                        { // current result is best.
                            result = current_result;
                        }
                    }
                }

                // evaluate the result.
                if (result.Weight < double.MaxValue)
                { // there is a result; apply it!
                    IRoute source = solution.Route(result.RouteSourceId);
                    IRoute target = solution.Route(result.RouteTargetId);

                    //string source_string = source.ToString();
                    //string target_string = target.ToString();

                    if (target.Count > 1 && target.First == target.GetNeigbours(result.CustomerTargetSource)[0])
                    {
                        //throw new Exception();
                    }

                    // create an enumeration of all customers of source in the correct order.
                    IEnumerable <int> source_between = new List <int>(
                        source.Between(result.CustomerSourceSource, result.CustomerSourceTarget));

                    // insert after the complete source.
                    int previous = result.CustomerTargetSource;
                    int next     = target.GetNeigbours(result.CustomerTargetSource)[0];
                    foreach (int source_customer in source_between)
                    {
                        // insert.
                        target.ReplaceEdgeFrom(previous, source_customer);

                        previous = source_customer; // update previous.
                    }
                    target.ReplaceEdgeFrom(previous, next);

                    // remove the source route.
                    solution.Remove(result.RouteSourceId);
                    solution.RemoveWeight(result.RouteTargetId);

                    // calculate the weight of the new route.
                    solution[result.RouteTargetId] = solution[result.RouteTargetId] + result.Weight +
                                                     solution[result.RouteSourceId];

                    if (!solution.IsValid())
                    {
                        throw new Exception();
                    }
                }
                else
                { // set the result null.
                    result = null;
                }
            }

            return(solution);
        }
        public void TestDepotDynamicAsymmetricMultiRouteExchanges()
        {
            // create two routes.
            // 0->11->12->13->14->15->0
            // 0->21->22->23->24->25->0
            var    multiRoute = new MaxTimeSolution(0);
            IRoute route1     = multiRoute.Add();
            var    customers  = new List <int>(route1);

            Assert.AreEqual(1, customers.Count);
            Assert.AreEqual(0, customers[0]);
            route1.InsertAfter(0, 11);
            Assert.AreEqual("0->11", route1.ToString());
            route1.InsertAfter(11, 12);
            route1.InsertAfter(12, 13);
            route1.InsertAfter(13, 14);
            route1.InsertAfter(14, 15);
            IRoute route2 = multiRoute.Add();

            customers = new List <int>(route2);
            Assert.AreEqual(1, customers.Count);
            Assert.AreEqual(0, customers[0]);
            route2.InsertAfter(0, 21);
            Assert.AreEqual("0->21", route2.ToString());
            route2.InsertAfter(21, 22);
            route2.InsertAfter(22, 23);
            route2.InsertAfter(23, 24);
            route2.InsertAfter(24, 25);

            customers = new List <int>(route1);
            Assert.AreEqual(6, customers.Count);
            Assert.AreEqual(0, customers[0]);
            Assert.AreEqual(11, customers[1]);
            Assert.AreEqual(12, customers[2]);
            Assert.AreEqual(13, customers[3]);
            Assert.AreEqual(14, customers[4]);
            Assert.AreEqual(15, customers[5]);


            customers = new List <int>(route2);
            Assert.AreEqual(6, customers.Count);
            Assert.AreEqual(0, customers[0]);
            Assert.AreEqual(21, customers[1]);
            Assert.AreEqual(22, customers[2]);
            Assert.AreEqual(23, customers[3]);
            Assert.AreEqual(24, customers[4]);
            Assert.AreEqual(25, customers[5]);

            // replace the entire first route.
            route1.ReplaceEdgeFrom(0, 0);

            route2.ReplaceEdgeFrom(25, 11);
            route2.ReplaceEdgeFrom(11, 12);
            route2.ReplaceEdgeFrom(12, 13);
            route2.ReplaceEdgeFrom(13, 14);
            route2.ReplaceEdgeFrom(14, 15);

            Assert.IsTrue(multiRoute.IsValid());

            // create two routes.
            // 0->11->12->13->14->15->0
            // 0->21->22->23->24->25->0
            multiRoute = new MaxTimeSolution(0);
            route1     = multiRoute.Add();
            customers  = new List <int>(route1);
            Assert.AreEqual(1, customers.Count);
            Assert.AreEqual(0, customers[0]);
            route1.InsertAfter(0, 11);
            Assert.AreEqual("0->11", route1.ToString());
            route1.InsertAfter(11, 12);
            route1.InsertAfter(12, 13);
            route1.InsertAfter(13, 14);
            route1.InsertAfter(14, 15);
            route2    = multiRoute.Add();
            customers = new List <int>(route2);
            Assert.AreEqual(1, customers.Count);
            Assert.AreEqual(0, customers[0]);
            route2.InsertAfter(0, 21);
            Assert.AreEqual("0->21", route2.ToString());
            route2.InsertAfter(21, 22);
            route2.InsertAfter(22, 23);
            route2.InsertAfter(23, 24);
            route2.InsertAfter(24, 25);

            // exchange parts.
            var part1 = new List <int>(route1.Between(11, 13));
            var part2 = new List <int>(route2.Between(23, 25));

            route1.ReplaceEdgeFrom(0, 14);
            route2.ReplaceEdgeFrom(22, 0);

            int previous = 0;

            for (int idx = 0; idx < part2.Count; idx++)
            {
                route1.ReplaceEdgeFrom(previous, part2[idx]);
                previous = part2[idx];
            }
            route1.ReplaceEdgeFrom(previous, 14);

            previous = 22;
            for (int idx = 0; idx < part1.Count; idx++)
            {
                route2.ReplaceEdgeFrom(previous, part1[idx]);
                previous = part1[idx];
            }
            route2.ReplaceEdgeFrom(previous, 0);

            Assert.IsTrue(multiRoute.IsValid());

            customers = new List <int>(route1);
            Assert.AreEqual(6, customers.Count);
            Assert.AreEqual(0, customers[0]);
            Assert.AreEqual(23, customers[1]);
            Assert.AreEqual(24, customers[2]);
            Assert.AreEqual(25, customers[3]);
            Assert.AreEqual(14, customers[4]);
            Assert.AreEqual(15, customers[5]);

            customers = new List <int>(route2);
            Assert.AreEqual(6, customers.Count);
            Assert.AreEqual(0, customers[0]);
            Assert.AreEqual(21, customers[1]);
            Assert.AreEqual(22, customers[2]);
            Assert.AreEqual(11, customers[3]);
            Assert.AreEqual(12, customers[4]);
            Assert.AreEqual(13, customers[5]);

            // create two routes.
            // 0->11->12->13->14->15->0
            // 0->21->22->23->24->25->0
            multiRoute = new MaxTimeSolution(0);
            route1     = multiRoute.Add();
            customers  = new List <int>(route1);
            Assert.AreEqual(1, customers.Count);
            Assert.AreEqual(0, customers[0]);
            route1.InsertAfter(0, 11);
            Assert.AreEqual("0->11", route1.ToString());
            route1.InsertAfter(11, 12);
            route1.InsertAfter(12, 13);
            route1.InsertAfter(13, 14);
            route1.InsertAfter(14, 15);
            route2    = multiRoute.Add();
            customers = new List <int>(route2);
            Assert.AreEqual(1, customers.Count);
            Assert.AreEqual(0, customers[0]);
            route2.InsertAfter(0, 21);
            Assert.AreEqual("0->21", route2.ToString());
            route2.InsertAfter(21, 22);
            route2.InsertAfter(22, 23);
            route2.InsertAfter(23, 24);
            route2.InsertAfter(24, 25);

            route1.ReplaceEdgeFrom(12, 15);
            route1.ReplaceEdgeFrom(14, 11);
            route1.ReplaceEdgeFrom(0, 13);

            customers = new List <int>(route1);
            Assert.AreEqual(6, customers.Count);
            Assert.AreEqual(0, customers[0]);
            Assert.AreEqual(13, customers[1]);
            Assert.AreEqual(14, customers[2]);
            Assert.AreEqual(11, customers[3]);
            Assert.AreEqual(12, customers[4]);
            Assert.AreEqual(15, customers[5]);

            route1.ToString();
        }