/// <summary>
/// Loads airport locations.
/// </summary>
/// <param name="numLocations">The number locations.</param>
/// <exception cref="Exception">Error parsing file</exception>
private static TravelingSalesmanDataset LoadAirports(int numLocations)
{
TravelingSalesmanDataset d;
Random rand;
List <string> lines;
int index;
string[] airport;
double lat, lon, x, y;
d = new TravelingSalesmanDataset();
rand = new Random(421784);
lines = File.ReadAllLines(@"./Resources/US Airports.txt").ToList();
if (numLocations > lines.Count)
{
numLocations = lines.Count;
}
try
{
for (int i = 0; i < numLocations; i++)
{
index = rand.Next(0, lines.Count);
airport = lines[index].Split('\t');
lat = double.Parse(airport[1]);
lon = double.Parse(airport[2]);
// Convert (lat,lon) to (x,y)
// https://stackoverflow.com/questions/14329691/convert-latitude-longitude-point-to-a-pixels-x-y-on-mercator-projection
x = (lon + 180.0) * (100.0 / 360.0);
y = (100.0 / 2.0) - (100.0 * Math.Log(Math.Tan((Math.PI / 4.0) + ((lat * Math.PI / 180.0) / 2.0))) / (2.0 * Math.PI));
d.AddLocation(new TravellingSalesmanGA.Location(airport[0], x, y));
lines.RemoveAt(index);
}
}
catch
{
// TODO handle different exceptions and provide better description of what went wrong
throw new Exception("Error parsing file");
}
d.Normalize(100, 100);
return(d);
}
public TravellingSalesmanGA(TravellingSalesmanParams p) :
base(p)
{
dataset = p.GetDataset();
locations = dataset.Locations;
genotypeLength = locations.Count - 2;
geneDomain = Enumerable.Range(1, genotypeLength).ToList();
LocationCount = locations.Count;
//TODO see performance of using pre-calculated distance
//distances = new Dictionary<LocationPair, double>(locations.Count);
//for (int i = 0; i < locations.Count; i++)
// for (int j = i; j < locations.Count; j++)
// {
// Location a = locations[i];
// Location b = locations[j];
// double distance = Math.Sqrt(Math.Pow(a.X - b.X, 2) + Math.Pow(a.Y - b.Y, 2));
// distances.Add(new LocationPair(a, b), distance);
// }
}
/// <summary>
/// Generates random locations.
/// </summary>
/// <param name="numLocations">The number locations.</param>
private static TravelingSalesmanDataset GenerateRandom(int numLocations, int?seed = null)
{
TravelingSalesmanDataset d;
Random rand;
d = new TravelingSalesmanDataset();
if (seed != null)
{
rand = new Random((int)seed);
}
else
{
rand = new Random();
}
for (int i = 0; i < numLocations; i++)
{
d.AddLocation(new TravellingSalesmanGA.Location("Location #" + i, rand.NextDouble() * 100, rand.NextDouble() * 100));
}
return(d);
}
/// <summary>
/// Generates locations in a circle pattern.
/// </summary>
/// <param name="numLocations">The number locations.</param>
/// <param name="altScale">The alt scale.</param>
/// <returns></returns>
private static TravelingSalesmanDataset GenerateCircle(int numLocations, double altScale = 1)
{
TravelingSalesmanDataset d;
double step;
d = new TravelingSalesmanDataset();
step = Math.PI / ((numLocations - 1) / 2);
for (int i = 1; i <= numLocations; i++)
{
if (i % 2 == 0)
{
d.AddLocation(new TravellingSalesmanGA.Location(i.ToString(), Math.Cos(step * i), Math.Sin(step * i)));
}
else
{
d.AddLocation(new TravellingSalesmanGA.Location(i.ToString(), Math.Cos(step * i) * altScale, Math.Sin(step * i) * altScale));
}
}
d.Normalize(100, 100);
return(d);
}
public TravelingSalesmanDataset GetDataset()
{
return(TravelingSalesmanDataset.Generate(DatasetType, NumLocations));
}