// Randomize starting placement
private void SelectFirstCity()
{
Random rand = new Random();
//select
_CurrentCity = _CitiesToVisit[rand.Next(0, _CitiesToVisit.Count - 1)];
//place to city
_CurrentCity.Receive(this, _CitiesToVisit);
}
// calculates decision param for next city
private double CalculateVariables(ACOCity to)
{
if (_CitiesToVisit.Contains(to))
{
ACODistance distance = (ACODistance)_CurrentCity.GetDistanceTo(to);
double length = distance.LengthDouble;
double pheromone = distance.Pheromone;
return(Math.Pow(1 / length, Convert.ToDouble(_Props.Beta)) * Math.Pow(pheromone, Convert.ToDouble(_Props.Alpha)));
}
return(0);
}
private void CopyGraph(TSPGraph <ACOCity, ACODistance> graph)
{
foreach (ACOCity mainCity in graph.GetCities())
{
ACOCity copiedCity = (ACOCity)mainCity.Clone();
for (int i = 0; i < graphState.GetCities().Count; i++)
{
ACODistance dist = (ACODistance)((ACODistance)mainCity.GetDistanceTo(graph.GetCities()[i])).Clone();
copiedCity.Connect(graphState.GetCities()[i], dist);
}
graphState.AddCity(copiedCity);
}
}
/// <summary>
/// Move Ant to next City
/// </summary>
/// <returns><c>ACOCity</c> where come.</returns>
public ACOCity GoNext()
{
//if bypass is not over
if (!HasFinished())
{
//decide wher go next
ACOCity cityToGo = MakeDecision();
//leave current
_CurrentCity.Release(this, _TabuList);
//go to next
_CurrentCity = cityToGo;
_CurrentCity.Receive(this, _CitiesToVisit);
}
return(_CurrentCity);
}
// ant makes decision using distance, pheromone and random value
private ACOCity MakeDecision()
{
ACOCity cityToGo = null;
Random random = new Random();
double randomValue = random.NextDouble();
double currentProb = 0;
foreach (KeyValuePair <ACOCity, double> entry in GetProbabilityTable())
{
currentProb += entry.Value;
if (randomValue <= currentProb)
{
cityToGo = entry.Key;
break;
}
}
return(cityToGo);
}
/// <summary>
/// Caculates probability of chance to go in mentiond City.
/// </summary>
/// <param name="to">City to go</param>
/// <returns>Probability from 0 to 1</returns>
protected double CalculateProbability(ACOCity to)
{
return(CalculateVariables(to) / CalculateVariables());
}
