/// <inheritdoc/>
/// <summary>
/// Looks for optimal solution of a function
/// </summary>
public virtual Harmony <T> SearchForHarmony()
{
InitializeHarmonyMemory();
ImprovisationCountWithTheSameBestValue = 0;
ImprovisationCount = 0;
while (SearchingShouldContinue())
{
var harmonyMemoryConsiderationRatio = ParameterProvider.HarmonyMemoryConsiderationRatio;
var pitchAdjustmentRatio = ParameterProvider.PitchAdjustmentRatio;
var improvisedHarmony = HarmonyGenerator.ImproviseHarmony(harmonyMemoryConsiderationRatio, pitchAdjustmentRatio);
var worstHarmony = HarmonyMemory.WorstHarmony;
if (improvisedHarmony.IsBetterThan(worstHarmony) && !HarmonyMemory.Contains(improvisedHarmony))
{
HarmonyMemory.SwapWithWorstHarmony(improvisedHarmony);
}
SaveBestHarmony(HarmonyMemory.BestHarmony);
ImprovisationCount++;
}
return(HarmonyMemory.BestHarmony);
}
/// <summary>
/// Resets this instance.
/// </summary>
public virtual void Reset()
{
ImprovisationCount = 0;
ImprovisationCountWithTheSameBestValue = 0;
BestHarmonyObjectiveValue = double.PositiveInfinity;
HarmonyMemory.Clear();
}
/// <summary>
/// Initializes harmony memory with random solutions
/// </summary>
public virtual void InitializeHarmonyMemory()
{
for (var i = 0; i < HarmonyMemory.MaxCapacity; i++)
{
var generateRandomHarmony = HarmonyGenerator.GenerateRandomHarmony();
HarmonyMemory.Add(generateRandomHarmony);
}
}
/// <summary>
/// Merges solutions from Harmony Memory and generated by Ant Colony optimization
/// </summary>
/// <param name="antColonySolutions">Ant colony solutions</param>
private void MergeHarmonyMemoryWithAntSolutions(IEnumerable <Harmony <T> > antColonySolutions)
{
var allHarmonies = HarmonyMemory.GetAll()
.Concat(antColonySolutions)
.OrderBy(h => h.ObjectiveValue)
.ToList();
HarmonyMemory.Clear();
HarmonyMemory.AddRange(allHarmonies);
}
/// <summary>
/// The constructor
/// </summary>
/// <param name="harmonyGenerator">Harmony generator</param>
/// <param name="parameterProvider"></param>
/// <param name="harmonyMemorySize">Harmony memory size</param>
/// <param name="maxImprovisationCount">Maximal improvisation count</param>
public HarmonySearcher(IHarmonyGenerator <T> harmonyGenerator, IParameterProvider parameterProvider, int harmonyMemorySize = DefaultHarmonyMemorySize, long maxImprovisationCount = DefaultMaxImprovisationCount)
{
MaxImprovisationCount = maxImprovisationCount;
HarmonyGenerator = harmonyGenerator ?? throw new ArgumentNullException(nameof(harmonyGenerator));
ParameterProvider = parameterProvider ?? throw new ArgumentNullException(nameof(parameterProvider));
HarmonyMemory = new HarmonyMemory <T>(harmonyMemorySize);
HarmonyGenerator.HarmonyMemory = HarmonyMemory;
BestHarmonyObjectiveValue = double.PositiveInfinity;
MaxImprovisationCountWithTheSameBestValue = (int)(maxImprovisationCount / 10);
}
/// <summary>
/// Looks for optimal solution of a function
/// </summary>
/// <returns></returns>
/// <inheritdoc/>
public override Harmony <T> SearchForHarmony()
{
InitializeHarmonyMemory();
ImprovisationCount = 0;
ImprovisationCountWithTheSameBestValue = 0;
while (SearchingShouldContinue())
{
var worstHarmony = HarmonyMemory.WorstHarmony;
// Get parameters
var harmonyMemoryConsiderationRatio = ParameterProvider.HarmonyMemoryConsiderationRatio;
var pitchAdjustmentRatio = ParameterProvider.PitchAdjustmentRatio;
// Improvise harmony with the new parameters
var improvisedHarmony = HarmonyGenerator.ImproviseHarmony(harmonyMemoryConsiderationRatio, pitchAdjustmentRatio);
if (improvisedHarmony.IsBetterThan(worstHarmony) && !HarmonyMemory.Contains(improvisedHarmony))
{
HarmonyMemory.SwapWithWorstHarmony(improvisedHarmony);
}
// Update global pheromone using the best harmony
_antColonyOptimizer.UpdateGlobalPheromone(HarmonyMemory.BestHarmony);
// Get ant solutions
var antSolutions = _antColonyOptimizer.GetAntColonySolutions(HarmonyMemory.MaxCapacity);
// Merge ant solutions with improvised ones
MergeHarmonyMemoryWithAntSolutions(antSolutions);
// Save best solution
SaveBestHarmony(HarmonyMemory.BestHarmony);
ImprovisationCount++;
}
return(HarmonyMemory.BestHarmony);
}