// --------------------------------------------------------------------------------------------
private static void UpdatePheromones(double[][] pheromones, int[][] ants, int[][] dists, object threadLock)
{
lock (threadLock) {
for (int i = 0; i <= pheromones.Length - 1; i++)
{
for (int j = i + 1; j <= pheromones[i].Length - 1; j++)
{
for (int k = 0; k <= ants.Length - 1; k++)
{
// length of ant k trail
double decrease = (1.0 - rho) * pheromones[i][j];
double increase = 0.0;
if (EdgeInTrail(i, j, ants[k]) == true)
{
double length = ACOExample.Length(ants[k], dists);
increase = (Q / length);
}
pheromones[i][j] = decrease + increase;
if (pheromones[i][j] < 0.0001)
{
pheromones[i][j] = 0.0001;
}
else if (pheromones[i][j] > 100000.0)
{
pheromones[i][j] = 100000.0;
}
pheromones[j][i] = pheromones[i][j];
}
}
}
}
}
static void Main(string[] args)
{
int scenario = 0;
switch (scenario)
{
case 0:
WorkQueueTest.Run();
break;
case 1:
ACOExample.Run();
break;
case 2:
ACO.ACOWithShappExample.Run(args);
break;
case 3:
ProgramForProtoTesting.MainMethod(args);
break;
case 4:
Program main = new Program();
main.Execute(args);
break;
}
}
public static void Run()
{
IList <int[][]> ants = new SynchronizedCollection <int[][]>();
IList <double[][]> pheromones = new SynchronizedCollection <double[][]>();
IList <object> locks = new SynchronizedCollection <object>();
IList <int> iterations = new SynchronizedCollection <int>();
try {
C.log.Info("Begin Ant Colony Optimization demo");
C.log.Info("Number cities in problem = " + numCities);
C.log.Info("Number ants = " + numAnts);
C.log.Info("Maximum time = " + maxTime);
C.log.Info("Alpha (pheromone influence) = " + alpha);
C.log.Info("Beta (local node influence) = " + beta);
C.log.Info("Rho (pheromone evaporation coefficient) = " + rho.ToString("F2"));
C.log.Info("Q (pheromone deposit factor) = " + Q.ToString("F2"));
C.log.Info("Initialing dummy graph distances");
int[][] dists = MakeGraphDistances(numCities);
C.log.Info("Initialing ants to random trails");
for (int i = 0; i < numThreads; ++i)
{
ants.Add(InitAnts(numAnts, numCities));
locks.Add(new object());
iterations.Add(0);
}
// initialize ants to random trails
ShowAnts(ants, dists);
int[] bestTrail = ACOExample.BestTrail(ants, dists, locks);
// determine the best initial trail
double bestLength = Length(bestTrail, dists);
// the length of the best trail
Console.Write("Best initial trail length: " + bestLength.ToString("F1") + "");
//Display(bestTrail);
C.log.Info("Initializing pheromones on trails");
for (int i = 0; i < numThreads; ++i)
{
pheromones.Add(InitPheromones(numCities));
}
List <Thread> threads = new List <Thread>();
for (int i = 0; i < numThreads; ++i)
{
threads.Add(new Thread(new ParameterizedThreadStart((threadIdxParam) => {
int threadIdx = (int)threadIdxParam;
C.log.Info("Sarting as " + threadIdx);
while (true)
{
UpdateAnts(ants[threadIdx], pheromones[threadIdx], dists, locks[threadIdx], randoms[threadIdx]);
UpdatePheromones(pheromones[threadIdx], ants[threadIdx], dists, locks[threadIdx]);
lock (locks[threadIdx]) {
iterations[threadIdx]++;
}
}
})));
}
for (int i = 0; i < numThreads; ++i)
{
threads[i].Start(i);
}
int startTime = GetTime();
int iteration = 0;
int lastSynchronisation = GetTime();
C.log.Info("Entering UpdateAnts - UpdatePheromones loop");
while (GetTime() - startTime < maxTime)
{
//for (int i = 0; i < numThreads; ++i)
// UpdateAnts(ants[i], pheromones[i], dists, locks[i]);
//for (int i = 0; i < numThreads; ++i)
// UpdatePheromones(pheromones[i], ants[i], dists, locks[i]);
if (GetTime() - lastSynchronisation >= synchronisationPeriod)
{
SynchronizePheromones(pheromones, locks);
}
if (GetTime() - bestLengthCheckPeriod >= 1)
{
int[] currBestTrail = ACOExample.BestTrail(ants, dists, locks);
double currBestLength = Length(currBestTrail, dists);
C.log.Info("length " + currBestLength.ToString("F1"));
int sumOfIterations = 0;
for (int i = 0; i < numThreads; ++i)
{
lock (locks[i]) {
sumOfIterations += iterations[i];
}
}
C.log.Info("iterations " + sumOfIterations);
if (currBestLength < bestLength)
{
bestLength = currBestLength;
bestTrail = currBestTrail;
C.log.Info("New best length of " + bestLength.ToString("F1") + " found at time " + iteration);
}
}
Thread.Sleep(500);
iteration += 1;
}
C.log.Info("Time complete");
C.log.Info("Best trail found:");
Display(bestTrail);
C.log.Info("Length of best trail found: " + bestLength.ToString("F1"));
C.log.Info("End Ant Colony Optimization demo");
Console.Read();
} catch (Exception ex) {
C.log.Info(ex.Message);
}
}