private Population GetPopulation()
{
string algorithmName = (string)algorithmsComboBox.SelectedItem;
string tspProblemName = (string)tspProblemsComboBox.SelectedItem;
IAlgorithm algorithm;
CitiesSequence citiesSequence;
switch (algorithmName)
{
case "Genetic algorithm":
algorithm = new GeneticAlgorithm();
break;
default:
throw new InvalidOperationException($"Algorithm '{algorithmName}' is not supported.");
}
switch (tspProblemName)
{
case "TSP problem 1":
citiesSequence = CitiesSequence.GetDefaultSequence();
break;
default:
throw new InvalidOperationException($"TSP problem '{tspProblemName}' is not supported.");
}
return(new Population(citiesSequence, algorithm));
}
public Population(CitiesSequence baseCitiesSequence, IAlgorithm algorithm, int populationSize = 50)
{
BaseCitiesSequence = baseCitiesSequence;
Algorithm = algorithm;
_populationSize = populationSize;
CreateNewPopulation();
}
public List <CitiesSequence> SeedPopulation(CitiesSequence baseSequence, int populationSize)
{
PopulationSize = populationSize;
return(Enumerable.Range(0, populationSize)
.Select(_ => GenerateRandomSequence(baseSequence))
.ToList());
}
private CitiesSequence CrossBreed(CitiesSequence s1, CitiesSequence s2)
{
int[] bounds = new int[2];
bounds[0] = bounds[1] = _random.Next(s1.Cities.Count); // probably should be -1
while (bounds[0] == bounds[1])
{
bounds[1] = _random.Next(s1.Cities.Count);
}
bounds = bounds.OrderBy(e => e).ToArray();
var availableCities = s1.Cities.ToList();
var usedCities = new List <City>();
var newSequence = new City[s1.Cities.Count];
for (int i = 0; i < s1.Cities.Count; i++)
{
// todo: check >= bound
if (i < bounds[0] || i >= bounds[1])
{
newSequence[i] = s1.Cities[i];
availableCities.Remove(s1.Cities[i]);
usedCities.Add(s1.Cities[i]);
}
}
// fill unused cities between bounds
for (int i = bounds[0]; i < bounds[1]; i++)
{
var tryCity = s2.Cities[i];
if (usedCities.Contains(tryCity))
{
newSequence[i] = availableCities.First();
availableCities.RemoveAt(0);
usedCities.Add(newSequence[i]);
}
else
{
newSequence[i] = tryCity;
availableCities.Remove(tryCity);
usedCities.Add(tryCity);
}
}
var result = new CitiesSequence();
result.Cities.AddRange(newSequence);
result.CalculateCost();
return(result);
}
private CitiesSequence GenerateRandomSequence(CitiesSequence baseSequence)
{
var availableCities = baseSequence.Cities.ToList();
var newSequence = new CitiesSequence();
while (availableCities.Count > 0)
{
var city = availableCities[_random.Next(availableCities.Count)];
availableCities.Remove(city);
newSequence.Cities.Add(city);
}
return(newSequence);
}
private void RandomMutation(CitiesSequence sequence)
{
// todo: make constant
if (_random.NextDouble() > 0.05)
{
int i1, i2;
i1 = i2 = _random.Next(sequence.Cities.Count);
while (i1 == i2)
{
i2 = _random.Next(sequence.Cities.Count);
}
var temp = sequence.Cities[i1];
sequence.Cities[i1] = sequence.Cities[i2];
sequence.Cities[i2] = temp;
}
sequence.CalculateCost();
}
