public Solution minimize(ProblemInstance instance, Evaluator evaluator)
{
Solution solution = new Solution(instance.m);
Cost cost = evaluator.evaluate(instance, solution);
int current_worker = 0;
for (int i = 0; i < instance.n; i++)
{
current_worker = MathUtils.argmin(cost.costs);
solution.job_ids[current_worker].Add(i);
cost = evaluator.evaluate(instance, solution);
}
solution.tag = "贪心算法";
return(solution);
}
public Cost evaluate(ProblemInstance instance, Solution solution)
{
Cost cost = new Cost();
cost.costs = new double[instance.m];
cost.totalCost = 0;
for (int i = 0; i < instance.m; i++)
{
cost.costs[i] = getDistanceOfWorker(i, instance, solution);
cost.totalCost += cost.costs[i];
}
cost.tag = "总路径长度";
return(cost);
}
public double getDistanceOfWorker(int workerID, ProblemInstance instance, Solution solution)
{
List <int> job_sequence = solution.job_ids[workerID];
if (job_sequence.Count == 0)
{
return(0);
}
double sum = distanceToZero(instance.job_details[job_sequence[0]]);
for (int i = 1; i < job_sequence.Count; i++)
{
sum += distance(instance.job_details[job_sequence[i - 1]], instance.job_details[job_sequence[i]]);
}
sum += distanceToZero(instance.job_details[job_sequence[job_sequence.Count - 1]]);
return(sum);
}
public Solution getSolution(ProblemInstance problem)
{
int machine_id = 0;
Solution solution = new Solution(problem.m);
for (int i = 0; i < data.Length; i++)
{
if (data[i] == -1)
{
machine_id++;
}
else
{
solution.job_ids[machine_id].Add(data[i]);
}
}
return(solution);
}
public static ProblemInstance getCustomProblemInstance()
{
ProblemInstance problemInstance = new ProblemInstance();
problemInstance.m = 2; //有几个骑士
problemInstance.n = 5; //有几个地理坐标
problemInstance.job_details = new JobDetails[problemInstance.n];
//因为n = 5，所以下面有5个坐标，最好在[-50, 50]之间，保证显示效果
int pointer = 0;
problemInstance.job_details[pointer++] = new JobDetails(10, 10);
problemInstance.job_details[pointer++] = new JobDetails(8, 10);
problemInstance.job_details[pointer++] = new JobDetails(6, 10);
problemInstance.job_details[pointer++] = new JobDetails(4, 10);
problemInstance.job_details[pointer++] = new JobDetails(2, 10);
return(problemInstance);
}
public static Solution getRandomSolution(ProblemInstance problem)
{
Solution solution = new Solution(problem.m);
List <int> order_ids = new List <int>(problem.n);
for (int i = 0; i < problem.n; i++)
{
order_ids.Add(i);
}
int selected_id = 0;
for (int i = 0; i < problem.n; i++)
{
selected_id = order_ids[MathUtils.u(0, order_ids.Count)];
order_ids.Remove(selected_id);
solution.job_ids[MathUtils.u(0, problem.m)].Add(selected_id);
}
return(solution);
}
public static DataPack parseDataPack(ProblemInstance problem, Solution solution)
{
DataPack dataPack = new DataPack();
dataPack.data = new int[problem.m + problem.n - 1];
int pointer = 0;
for (int i = 0; i < problem.m; i++)
{
if (i > 0)
{
dataPack.data[pointer++] = -1;
}
for (int j = 0; j < solution.job_ids[i].Count; j++)
{
dataPack.data[pointer++] = solution.job_ids[i][j];
}
}
return(dataPack);
}
public Solution minimize(ProblemInstance problem, Evaluator evaluator)
{
this.problem = problem;
this.evaluator = evaluator;
Solution solution = new Solution(problem.m);
List <int> order_ids = new List <int>();
for (int i = 0; i < problem.n; i++)
{
order_ids.Add(i);
}
order_ids.Sort((x, y) =>
{
JobDetails job_x = problem.job_details[x];
JobDetails job_y = problem.job_details[y];
double d = angles(job_x) - angles(job_y);
if (d < 0)
{
return(-1);
}
if (d == 0)
{
return(0);
}
return(1);
});
int jobPerMachine = 1 + problem.n / problem.m, machine_id;
for (int i = 0; i < problem.n; i++)
{
machine_id = i / jobPerMachine;
solution.job_ids[machine_id].Add(order_ids[i]);
}
solution.tag = "扫描算法";
return(solution);
}
public Solution minimize(ProblemInstance problem, Evaluator evaluator)
{
DataPack g_best = DataPack.parseDataPack(problem, SolutionUtils.getRandomSolution(problem));
double g_best_value = g_best.getValue(problem, evaluator);
double last_value = -1;
List <Particle> particles = new List <Particle>();
for (int i = 0; i < population_size; i++)
{
particles.Add(new Particle(problem, evaluator));
}
Optimizer optimizer = new ImprovedGreedyOptimizer();
particles.Add(new Particle(problem, evaluator, optimizer.minimize(problem, evaluator)));
optimizer = new ScannerOptimizer();
particles.Add(new Particle(problem, evaluator, optimizer.minimize(problem, evaluator)));
for (int i = 0; i < iteration_times; i++)
{
foreach (Particle particle in particles)
{
particle.update(ref g_best, ref g_best_value, particles);
}
if (last_value != g_best_value)
{
last_value = g_best_value;
Console.WriteLine("OPT = " + last_value.ToString());
}
}
Solution solution = g_best.getSolution(problem);
solution.tag = "粒子群优化算法";
return(solution);
}
public SolutionViewer(ProblemInstance problem, Solution solution, Cost cost, String title)
{
InitializeComponent();
WorkCanvas wc = new WorkCanvas(pictureBox1.Width, pictureBox1.Height, problem, solution, cost, title);
}
public double getValue(ProblemInstance problem, Evaluator evaluator)
{
return(evaluator.evaluate(problem, getSolution(problem)).totalCost);
}