public override void GenerateCandidates(ref List <ICandidate> candidates, int targetPopNumber = -1)
{
/* if no population size is provided, then it is assumed that the population should
* double from the current one. */
if (targetPopNumber == -1)
{
targetPopNumber = candidates.Count;
}
else
{
targetPopNumber -= candidates.Count;
}
var numNew = 0;
while (numNew < targetPopNumber)
{
var parent1 = candidates[(numNew) % candidates.Count].x;
var parent2 = candidates[(numNew + 1) % candidates.Count].x;
var child1 = (double[])parent1.Clone();
var child2 = (double[])parent2.Clone();
var ChangeMade = false;
for (var i = 1; i < bitStringLength; i++)
{
if (rnd.NextDouble() < xRatePerBit)
{
ChangeMade = true;
var varIndex = BitByteHexFunctions.FindVariableIndex(limits, i);
if (varIndex + 1 < n)
{
/* switch the remaining double values. No need to encode/decode them.*/
var tailLength = n - varIndex - 1;
var child1Tail = new double[tailLength];
Array.Copy(child1, varIndex + 1, child1Tail, 0, tailLength);
Array.Copy(child2, varIndex + 1, child1, varIndex + 1, tailLength);
Array.Copy(child1Tail, 0, child2, varIndex + 1, tailLength);
}
var c1Value = discreteSpaceDescriptor[varIndex].PositionOf(child1[varIndex]);
var c1BitArray = BitByteHexFunctions.Encode(c1Value,
limits[varIndex].EndIndex -
limits[varIndex].StartIndex);
var c2Value = discreteSpaceDescriptor[varIndex].PositionOf(child2[varIndex]);
var c2BitArray = BitByteHexFunctions.Encode(c2Value,
limits[varIndex].EndIndex -
limits[varIndex].StartIndex);
BitByteHexFunctions.CrossoverBitString(c1BitArray, c2BitArray,
i - limits[varIndex].StartIndex,
limits[varIndex].MaxValue, out c1Value,
out c2Value);
child1[varIndex] = discreteSpaceDescriptor[varIndex][c1Value];
child2[varIndex] = discreteSpaceDescriptor[varIndex][c2Value];
}
}
if (ChangeMade)
{
numNew += 2;
candidates.Add(new Candidate(double.NaN, child1));
candidates.Add(new Candidate(double.NaN, child2));
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="BitStringNeighborGenerator"/> class.
/// </summary>
/// <param name="discreteSpaceDescriptor">The discrete space descriptor.</param>
public BitStringNeighborGenerator(DesignSpaceDescription discreteSpaceDescriptor)
: base(discreteSpaceDescriptor)
{
limits = BitByteHexFunctions.InitializeBitString(discreteSpaceDescriptor);
bitStringLength = limits[n - 1].EndIndex;
rnd = new Random();
}
public GACrossoverBitString(DesignSpaceDescription discreteSpaceDescriptor, double crossoverRate = 1.7)
: base(discreteSpaceDescriptor)
{
limits = BitByteHexFunctions.InitializeBitString(discreteSpaceDescriptor);
bitStringLength = limits[n - 1].EndIndex;
xRatePerBit = crossoverRate / bitStringLength;
rnd = new Random();
}
public GAMutationBitString(DesignSpaceDescription discreteSpaceDescriptor, double mutationRate = 0.1)
: base(discreteSpaceDescriptor)
{
limits = BitByteHexFunctions.InitializeBitString(discreteSpaceDescriptor);
bitStringLength = limits[n - 1].EndIndex;
mRatePerBit = mutationRate / bitStringLength;
rnd = new Random();
}
/// <summary>
/// Generates the candidates.
/// </summary>
/// <param name="candidate">The candidate.</param>
/// <param name="numToCreate">The number to create.</param>
/// <returns>List<System.Double[]>.</returns>
public override List <double[]> GenerateCandidates(double[] candidate, int numToCreate = -1)
{
var newCands = new List <double[]>();
if (numToCreate == -1)
{
numToCreate = 1;
}
while (numToCreate-- > 0)
{
var result = (double[])candidate.Clone();
var j = rnd.Next(bitStringLength);
var varIndex = BitByteHexFunctions.FindVariableIndex(limits, j);
var valueIndex = discreteSpaceDescriptor[varIndex].PositionOf(result[varIndex]);
valueIndex = BitByteHexFunctions.FlipBit(valueIndex, limits[varIndex], j);
result[varIndex] = discreteSpaceDescriptor[varIndex][valueIndex];
newCands.Add(result);
}
return(newCands);
}
public override void GenerateCandidates(ref List <ICandidate> candidates, int control = -1)
{
for (var i = candidates.Count - 1; i >= 0; i--)
{
var candidate = candidates[i].x;
var ChangeMade = false;
for (var j = 0; j < bitStringLength; j++)
{
if (rnd.NextDouble() < mRatePerBit)
{
ChangeMade = true;
var varIndex = BitByteHexFunctions.FindVariableIndex(limits, j);
var valueIndex = discreteSpaceDescriptor[varIndex].PositionOf(candidate[varIndex]);
valueIndex = BitByteHexFunctions.FlipBit(valueIndex, limits[varIndex], j);
candidate[varIndex] = discreteSpaceDescriptor[varIndex][valueIndex];
}
}
if (ChangeMade)
{
candidates.RemoveAt(i);
candidates.Add(new Candidate(double.NaN, candidate));
}
}
}
