/// <summary>
/// Factory to create specified optimizer
/// </summary>
/// <param name="tspOptimizerAlgorithm"></param>
/// <param name="startSequence"></param>
/// <param name="euclideanPath"></param>
/// <returns></returns>
public static ITspOptimizer Create(TspOptimizerAlgorithm tspOptimizerAlgorithm,
int[] startSequence, IEuclideanPath euclideanPath,
OptimizerConfig config)
{
ITspOptimizer tspOptimizer = null;
switch (tspOptimizerAlgorithm)
{
case TspOptimizerAlgorithm.RandomOptimizer:
tspOptimizer = new RandomOptimizer(startSequence, euclideanPath, config);
break;
case TspOptimizerAlgorithm.LocalCombinationOptimizer:
tspOptimizer = new LocalCombinationOptimizer(startSequence, euclideanPath, config);
break;
case TspOptimizerAlgorithm.MultiLocalCombinationOptimizer:
tspOptimizer = new MultiLocalCombinationOptimizer(startSequence, euclideanPath, config);
break;
case TspOptimizerAlgorithm.LocalTwoOptOptimizer:
tspOptimizer = new LocalTwoOptOptimizer(startSequence, euclideanPath, config);
break;
case TspOptimizerAlgorithm.BruteForceOptimizer:
tspOptimizer = new BruteForceOptimizer(startSequence, euclideanPath, config);
break;
case TspOptimizerAlgorithm.BranchAndBoundOptimizer:
tspOptimizer = new BranchAndBoundOptimizer(startSequence, euclideanPath, config);
break;
case TspOptimizerAlgorithm.SimulatedAnnealingOptimizer:
tspOptimizer = new SimulatedAnnealingOptimizer(startSequence, euclideanPath, config);
break;
case TspOptimizerAlgorithm.GeneticOptimizer:
tspOptimizer = new GeneticOptimizer(startSequence, euclideanPath, config);
break;
default:
throw new ArgumentException("Unknown optimizer");
}
return(tspOptimizer);
}
public override void Start(CancellationToken token, Action <double> action)
{
_token = token;
_action = action;
// Do pre optimization -> early cuts in branches
var preOptimizer = new LocalTwoOptOptimizer(_startPermutation, _euclideanPath, _config);
preOptimizer.Start(1, false, 1);
var preOptimalSequence = preOptimizer.OptimalSequence;
_optimalSequence.OnNext(preOptimalSequence.ToArray());
_minPathLength = _euclideanPath.GetPathLength(preOptimalSequence, ClosedPath);
action?.Invoke(_minPathLength);
Permute(_startPermutation, 0, _startPermutation.Length - 1);
_optimalSequence.OnCompleted();
}
private void SetPopulationPool(int[,] chromosomePool, double[] distances)
{
if (_config.UseBigValleySearch)
{
Tuple <double, int[]>[] randomSequences = new Tuple <double, int[]> [_population];
ParallelOptions parallelOptions = new ParallelOptions
{
CancellationToken = _token,
MaxDegreeOfParallelism = _config.NumberOfCores
};
int count = 0;
try
{
Parallel.For(0, _population, parallelOptions, i =>
{
int[] sequence = Enumerable.Range(0, _number).ToArray();
Helper.Shuffle(sequence);
var twoOptOptimizer = new LocalTwoOptOptimizer(sequence, _euclideanPath, _config);
twoOptOptimizer.Start(1, true, _config.BigValleySearchRate);
var distance = _euclideanPath.GetPathLength(twoOptOptimizer.OptimalSequence, ClosedPath);
randomSequences[i] = new Tuple <double, int[]>(distance, twoOptOptimizer.OptimalSequence);
if (count++ % 10 == 0)
{
OptimizerInfo.OnNext("Progress Big-Valley-Search: " +
Math.Round(count / (double)_population * 100d, 2).ToString() + "%");
}
});
var orderedSequences = randomSequences.OrderBy(tuple => tuple.Item1).ToArray();
for (int p = 0; p < _population; p++)
{
distances[p] = orderedSequences[p].Item1;
int[] sequence = orderedSequences[p].Item2;
for (int n = 0; n < _number; n++)
{
chromosomePool[p, n] = sequence[n];
}
}
MinTour = orderedSequences.First().Item2.ToArray();
MinDistance = orderedSequences.First().Item1;
}
catch (OperationCanceledException)
{
OptimizerInfo.OnNext("Big-Valley-Search canceled");
}
if (!_token.IsCancellationRequested)
{
OptimizerInfo.OnNext("Big-Valley-Search completed");
}
}
else
{
for (int p = 0; p < _population; p++)
{
int[] city = Enumerable.Range(0, _number).ToArray();
Helper.Shuffle(city);
for (int n = 0; n < _number; n++)
{
chromosomePool[p, n] = city[n];
}
distances[p] = TourDistance(city);
if (distances[p] < MinDistance)
{
MinDistance = distances[p];
for (int n = 0; n < _number; n++)
{
MinTour[n] = chromosomePool[p, n];
}
}
}
}
if (!_token.IsCancellationRequested)
{
OptimizerInfo.OnNext("Population initialized");
}
}