protected override void PerformMutate(IChromosome chromosome, float probability)
{
if (RandomizationProvider.Current.GetDouble() <= probability)
{
int index = RandomizationProvider.Current.GetInt(0, chromosome.Length);
ExpressionGene gene = chromosome.GetGene(index).Value as ExpressionGene;
if (gene.Type == GeneType.Operator)
{
Operator op = (Operator)RandomizationProvider.Current.GetInt(0, Enum.GetNames(typeof(Operator)).Length);
chromosome.ReplaceGene(index, new Gene(new ExpressionGene(GeneType.Operator, op)));
}
else
{
// Number or Variable
GeneType type = (GeneType)RandomizationProvider.Current.GetInt(1, 3);
if (type == GeneType.Number)
{
double num = RandomizationProvider.Current.GetDouble(-10, 10); // Get from outside
chromosome.ReplaceGene(index, new Gene(new ExpressionGene(type, null, num)));
}
else if (type == GeneType.Variable)
{
int variable = RandomizationProvider.Current.GetInt(0, variableCount);
chromosome.ReplaceGene(index, new Gene(new ExpressionGene(type, null, 0, variable)));
}
}
}
}
public static double EvaluatePrefix(Gene[] genes, params double[] variables)
{
ExpressionGene[] prefix = genes.Select(x => x.Value).Cast <ExpressionGene>().ToArray();
Stack <double> stack = new Stack <double>();
for (int i = prefix.Length - 1; i >= 0; i--)
{
ExpressionGene gene = prefix[i];
if (gene.Type == GeneType.Number)
{
stack.Push(gene.Number);
}
else if (gene.Type == GeneType.Variable)
{
stack.Push(variables[gene.Variable]);
}
else
{
double a = stack.Pop();
double b = stack.Pop();
stack.Push(Compute(a, b, gene.Operator));
}
}
return(stack.Pop());
}
//private Gene[] GetSubtree(Gene[] genes, int index)
//{
// Gene gene = genes[index];
// Stack<Gene> operators = new Stack<Gene>();
// Stack<Gene> values = new Stack<Gene>();
// int valCount = 0;
// int i = index + 1;
// if ((gene.Value as ExpressionGene).Type == GeneType.Operator)
// operators.Push(gene);
// else
// values.Push(gene);
// while (operators.Count > 0 && i < genes.Length)
// {
// gene = genes[i];
// if ((gene.Value as ExpressionGene).Type != GeneType.Operator && valCount > 0)
// {
// double value = PrefixHelper.Compute(GetGeneValue(values.Pop()), GetGeneValue(gene), (operators.Pop().Value as ExpressionGene).Operator);
// values.Push(new Gene(new ExpressionGene(GeneType.Number,null ,value)));
// while (values.Count > 2 && operators.Count > 0)
// {
// value = PrefixHelper.Compute(GetGeneValue(values.Pop()), GetGeneValue(values.Pop()), (operators.Pop().Value as ExpressionGene).Operator);
// values.Push(new Gene(new ExpressionGene(GeneType.Number, null, value)));
// }
// if (operators.Count == 0 && values.Count == 1)
// {
// i++;
// break;
// }
// if (values.Count == 0)
// valCount = 0;
// }
// else if ((gene.Value as ExpressionGene).Type == GeneType.Operator)
// {
// operators.Push(gene);
// valCount = 0;
// }
// else
// {
// double value = GetGeneValue(gene);
// values.Push(new Gene(new ExpressionGene(GeneType.Number, null, value)));
// valCount++;
// }
// i++;
// }
// if (Math.Abs(index - i) % 2 == 0)
// {
// i--;
// }
// return genes.Slice(index, i);
//}
private Gene[] GetSubtree(Gene[] genes, int index)
{
int ops = 0;
int nums = 0;
int i = index;
for (; i < genes.Length; i++)
{
ExpressionGene eg = genes[i].Value as ExpressionGene;
if (eg.Type == GeneType.Operator)
{
ops++;
}
else
{
nums++;
}
if (nums == ops + 1)
{
break;
}
}
return(genes.Slice(index, i + 1));
}
public double Evaluate(params double[] variables)
{
Stack <double> stack = new Stack <double>();
for (int i = Length - 1; i >= 0; i--)
{
ExpressionGene gene = m_genes[i].Value as ExpressionGene;
switch (gene.Type)
{
case GeneType.Number:
stack.Push(gene.Number);
break;
case GeneType.Variable:
stack.Push(variables[gene.Variable]);
break;
case GeneType.Operator:
double a = stack.Pop();
double b = stack.Pop();
stack.Push(PrefixHelper.Compute(a, b, gene.Operator));
break;
default:
break;
}
}
return(stack.Pop());
}
public override Gene GenerateGene(int geneIndex)
{
ExpressionGene expression = new ExpressionGene();
//int value = RandomizationProvider.Current.GetInt(minValue, maxValue);
return(new Gene(expression));
}
private double GetGeneValue(Gene gene)
{
ExpressionGene eg = gene.Value as ExpressionGene;
switch (eg.Type)
{
case GeneType.Number:
return(eg.Number);
case GeneType.Variable:
return(1);
case GeneType.Operator:
default:
throw new ArgumentException();
}
}
public int CompareTo(ExpressionGene other)
{
if (other == null)
{
return(-1);
}
if (other.Type != Type)
{
return(-1);
}
switch (Type)
{
case GeneType.Operator:
if (other.Operator != Operator)
{
return(-1);
}
break;
case GeneType.Number:
if (other.Number != Number)
{
return(-1);
}
break;
case GeneType.Variable:
if (other.Variable != Variable)
{
return(-1);
}
break;
}
return(0);
}
