private void MutateSingle(TermExpression expression, int factorSimpleMutation)
{
var lengthTokensTable = tokensTable.Count();
var rnd = new Random();
var tablePosition = rnd.Next(lengthTokensTable - 1);
var lengthEpression = expression.ExpressionTokens.Length;
var position = rnd.Next(lengthEpression - 1);
var typeMutation = rnd.Next(factorSimpleMutation);
if (typeMutation != 0)
{
//mutate element
expression.ExpressionTokens[position] = tokensTable.ElementAt(tablePosition);
}
else
{
//add element to end
var token = tokensTable.ElementAt(tablePosition);
var expr = expression.ExpressionTokens.ToList();
expr.Add(token);
if (!token.IsTerminal)
{
var terminals = tokensTable.Where(x => x.IsTerminal);
var countTerminals = terminals.Count();
for (var i = 0; i < token.Arity; i++)
{
expr.Add(terminals.ElementAt(rnd.Next(countTerminals - 1)));
}
}
}
}
private ICollection <TermExpression> Recombine(TermExpression item, TermExpression secondItem)
{
var firstLength = item.ExpressionTokens.Length;
var seconfLength = secondItem.ExpressionTokens.Length;
var tokenLength = (firstLength > seconfLength) ? seconfLength : firstLength;
var takePositions = new Random().Next(tokenLength - 1);
var firstParticleOfFirst = item.ExpressionTokens.Take(takePositions).AsEnumerable();
var SecondParticleOfFirst = item.ExpressionTokens.Skip(takePositions).AsEnumerable();
var firstParticleOfSecond = secondItem.ExpressionTokens.Take(takePositions).AsEnumerable();
var SecondParticleOfSecond = secondItem.ExpressionTokens.Skip(takePositions).AsEnumerable();
var result = new List <TermExpression>
{
new TermExpression
{
ExpressionTokens = Enumerable.Concat(firstParticleOfFirst, SecondParticleOfSecond).ToArray(),
},
new TermExpression
{
ExpressionTokens = Enumerable.Concat(firstParticleOfSecond, SecondParticleOfFirst).ToArray(),
}
};
return(result);
}
