Esempio n. 1
0
        internal void GlobalPheromoneUpdate(List <Node> mainSolution, Fitness mainSolutionFitnessValue, List <Edge> edges)
        {
            foreach (var node in mainSolution)
            {
                if (mainSolution.Last() == node)
                {
                    break;
                }

                var nextNode = mainSolution.First(n => n.NurseId == node.NurseId + 1);

                var solutionEdge = edges.First(ed => ed.IndexNurseA == node.NurseId && ed.IndexNurseB == nextNode.NurseId && ed.IndexNodeA == node.Index && ed.IndexNodeB == nextNode.Index);
                solutionEdge.Pheromone = (1.0 - PARAM_RHO) * solutionEdge.Pheromone + PARAM_RHO * (1 / (1 + mainSolutionFitnessValue.CompleteFitnessValue * PARAM_LAMBDA));
            }
        }
Esempio n. 2
0
        static void Main(string[] args)
        {
            var        inputData = InputData.GetObjectDataFromFile("Instances/Sprint/sprint02.xml");
            ACOHandler handler   = new ACOHandler(inputData);

            List <Node>[] nodes = handler.GenerationManager.GetShiftPatterns();

            //List<Node>[] nodes = NodeTest();
            List <Edge> edges = new List <Edge>();

            handler.ComputeStaticHeuristic(nodes);
            List <Node> mainSolution             = handler.ExtractSolution(nodes);
            Fitness     mainSolutionFitnessValue = handler.ApplySolution(mainSolution).Item1;

            handler.InitializeStandardPheromone(mainSolutionFitnessValue);
            handler.ListOfEdgesUpdate(mainSolution, edges);

            int consecutiveNoImprovements = 0;

            Console.Write("Solution construction ");
            do
            {
                Console.Write(".");
                List <Ant> ants = Ant.GenerateAnts(NUM_ANTS, handler.CoverRequirements, handler.CoverRequirementsArray);
                foreach (var ant in ants)
                {
                    Console.Write(":");
                    for (int i = 0; i < handler.NurseNumber; i++)
                    {
                        //Compute the product between static heuristic and dynamic heuristic
                        var heuristicInformation = handler.ComputeHeuristicInfo(nodes[i], ant.CoverRequirementsArray);
                        var selectedIndex        = handler.NodeSelection(heuristicInformation, nodes, edges, i);
                        var selectedNode         = nodes[i].ElementAt(selectedIndex);
                        ant.Solution.Add(selectedNode);
                        ant.CoverRequirementsArray = heuristicInformation[selectedIndex].Item2;
                    }

                    Tuple <Fitness, int[]> antSolutionApplied = handler.ApplySolution(ant.Solution);
                    int[] antSolutionUpdatedCoverReq          = antSolutionApplied.Item2;

                    //Edges update
                    handler.ListOfEdgesUpdate(ant.Solution, edges);

                    if (Fitness.FitnessCompare(antSolutionApplied.Item1, mainSolutionFitnessValue) == 1)
                    {
                        mainSolution              = ant.Solution;
                        mainSolutionFitnessValue  = antSolutionApplied.Item1;
                        consecutiveNoImprovements = 0;
                        Console.Write($" {antSolutionApplied.Item1.UncoveredShifts} + {antSolutionApplied.Item1.TotalOverShift} + {antSolutionApplied.Item1.TotalSolutionCost} ");
                    }
                    else
                    {
                        consecutiveNoImprovements++;
                    }
                    handler.LocalPheromoneUpdate(mainSolution, edges);
                }

                handler.GlobalPheromoneUpdate(mainSolution, mainSolutionFitnessValue, edges);
            } while (consecutiveNoImprovements < NO_IMPROVEMENT_LIMIT);

            handler.Evaluator.CalculateSolutionPenalty(mainSolution);
            handler.GenerationManager.PrintSolution(mainSolution, mainSolutionFitnessValue);

            Console.ReadKey();
        }
Esempio n. 3
0
 internal void InitializeStandardPheromone(Fitness fitness)
 {
     Pheromone_0        = 1.0 / (fitness.CompleteFitnessValue + 1.0);
     CurrentPheromone_0 = Pheromone_0;
 }