public ConditionExpression(List <IExpression> expressions, FuzzyCondition condition)
{
_expressions = expressions;
_condition = condition;
}
static private List <IExpression> ExtractSingleCondidtions(List <IExpression> conditionExpression, List <FuzzyVariable> input, Dictionary <string, Lexem> lexems)
{
List <IExpression> copyExpressions = conditionExpression.GetRange(0, conditionExpression.Count);
List <IExpression> expressions = new List <IExpression>();
while (copyExpressions.Count > 0)
{
if (copyExpressions[0] is VarLexem <FuzzyVariable> )
{
//
// Parse variable
//
VarLexem <FuzzyVariable> varLexem = (VarLexem <FuzzyVariable>)copyExpressions[0];
if (copyExpressions.Count < 3)
{
throw new Exception(string.Format("Condition strated with '{0}' is incorrect.", varLexem.Text));
}
if (varLexem.Input == false)
{
throw new Exception("The variable in condition part must be an input variable.");
}
//
// Parse 'is' lexem
//
Lexem exprIs = (Lexem)copyExpressions[1];
if (exprIs != lexems["is"])
{
throw new Exception(string.Format("'is' keyword must go after {0} identifier.", varLexem.Text));
}
//
// Parse 'not' lexem (if exists)
//
int cur = 2;
bool not = false;
if (copyExpressions[cur] == lexems["not"])
{
not = true;
cur++;
if (copyExpressions.Count <= cur)
{
throw new Exception("Error at 'not' in condition part of the rule.");
}
}
//"slightly"
//"somewhat"
//"very"
//"extremely"
//
// Parse hedge modifier (if exists)
//
HedgeType hedge = HedgeType.None;
if (copyExpressions[cur] == lexems["slightly"])
{
hedge = HedgeType.Slightly;
}
else if (copyExpressions[cur] == lexems["somewhat"])
{
hedge = HedgeType.Somewhat;
}
else if (copyExpressions[cur] == lexems["very"])
{
hedge = HedgeType.Very;
}
else if (copyExpressions[cur] == lexems["extremely"])
{
hedge = HedgeType.Extremely;
}
if (hedge != HedgeType.None)
{
cur++;
if (copyExpressions.Count <= cur)
{
throw new Exception(string.Format("Error at '{0}' in condition part of the rule.", hedge.ToString().ToLower()));
}
}
//
// Parse term
//
Lexem exprTerm = (Lexem)copyExpressions[cur];
if (!(exprTerm is IAltLexem))
{
throw new Exception(string.Format("Wrong identifier '{0}' in conditional part of the rule.", exprTerm.Text));
}
IAltLexem altLexem = (IAltLexem)exprTerm;
TermLexem <FuzzyTerm> termLexem = null;
do
{
if (!(altLexem is TermLexem <FuzzyTerm>))
{
continue;
}
termLexem = (TermLexem <FuzzyTerm>)altLexem;
if (!varLexem.Var.Values.Contains(termLexem.Term))
{
termLexem = null;
continue;
}
}while ((altLexem = altLexem.Alternative) != null && termLexem == null);
if (termLexem == null)
{
throw new Exception(string.Format("Wrong identifier '{0}' in conditional part of the rule.", exprTerm.Text));
}
//
// Add new condition expression
//
FuzzyCondition condition = new FuzzyCondition(varLexem.Var, termLexem.Term, not, hedge);
expressions.Add(new ConditionExpression(copyExpressions.GetRange(0, cur + 1), condition));
copyExpressions.RemoveRange(0, cur + 1);
}
else
{
IExpression expr = copyExpressions[0];
if (expr == lexems["and"] ||
expr == lexems["or"] ||
expr == lexems["("] ||
expr == lexems[")"])
{
expressions.Add(expr);
copyExpressions.RemoveAt(0);
}
else
{
Lexem unknownLexem = (Lexem)expr;
throw new Exception(string.Format("Lexem '{0}' found at the wrong place in condition part of the rule.", unknownLexem.Text));
}
}
}
return(expressions);
}
/// <summary>
/// Evaluate fuzzy condition (or conditions)
/// </summary>
/// <param name="condition">Condition that should be evaluated</param>
/// <param name="fuzzifiedInput">Input in fuzzified form</param>
/// <returns>Result of evaluation</returns>
protected double EvaluateCondition(ICondition condition, Dictionary <FuzzyVariable, Dictionary <FuzzyTerm, double> > fuzzifiedInput)
{
if (condition is Conditions)
{
double result = 0.0;
Conditions conds = (Conditions)condition;
if (conds.ConditionsList.Count == 0)
{
throw new Exception("Inner exception.");
}
else if (conds.ConditionsList.Count == 1)
{
result = EvaluateCondition(conds.ConditionsList[0], fuzzifiedInput);
}
else
{
result = EvaluateCondition(conds.ConditionsList[0], fuzzifiedInput);
for (int i = 1; i < conds.ConditionsList.Count; i++)
{
result = EvaluateConditionPair(result, EvaluateCondition(conds.ConditionsList[i], fuzzifiedInput), conds.Op);
}
}
if (conds.Not)
{
result = 1.0 - result;
}
return(result);
}
else if (condition is FuzzyCondition)
{
FuzzyCondition cond = (FuzzyCondition)condition;
double result = fuzzifiedInput[(FuzzyVariable)cond.Var][(FuzzyTerm)cond.Term];
switch (cond.Hedge)
{
case HedgeType.Slightly:
result = Math.Pow(result, 1.0 / 3.0); //Cube root
break;
case HedgeType.Somewhat:
result = Math.Sqrt(result);
break;
case HedgeType.Very:
result = result * result;
break;
case HedgeType.Extremely:
result = result * result * result;
break;
default:
break;
}
if (cond.Not)
{
result = 1.0 - result;
}
return(result);
}
else
{
throw new Exception("Internal exception.");
}
}