GetVariable() public méthode

Returns an existing linguistic variable from the database.
The variable indicated was not found in the database.
public GetVariable ( string variableName ) : LinguisticVariable
variableName string Name of the linguistic variable to retrieve.
Résultat LinguisticVariable
        /// <summary>
        /// Executes the fuzzy inference, obtaining the <see cref="FuzzyOutput"/> of the system for the required
        /// <see cref="LinguisticVariable"/>.
        /// </summary>
        ///
        /// <param name="variableName">Name of the <see cref="LinguisticVariable"/> to evaluate.</param>
        ///
        /// <returns>A <see cref="FuzzyOutput"/> containing the fuzzy output of the system for the
        /// <see cref="LinguisticVariable"/> specified in <paramref name="variableName"/>.</returns>
        ///
        /// <exception cref="KeyNotFoundException">The variable indicated was not found in the database.</exception>
        ///
        public FuzzyOutput ExecuteInference(string variableName)
        {
            // gets the variable
            LinguisticVariable lingVar = database.GetVariable(variableName);

            // object to store the fuzzy output
            FuzzyOutput fuzzyOutput = new FuzzyOutput(lingVar);

            // select only rules with the variable as output
            Rule[] rules = rulebase.GetRules( );
            foreach (Rule r in rules)
            {
                if (r.Output.Variable.Name == variableName)
                {
                    string labelName      = r.Output.Label.Name;
                    float  firingStrength = r.EvaluateFiringStrength( );
                    if (firingStrength > 0)
                    {
                        fuzzyOutput.AddOutput(labelName, firingStrength);
                    }
                }
            }

            // returns the fuzzy output obtained
            return(fuzzyOutput);
        }
        /// <summary>
        /// Converts the Fuzzy Rule to RPN (Reverse Polish Notation). For debug proposes, the string representation of the
        /// RPN expression can be acessed by calling <see cref="GetRPNExpression"/> method.
        /// </summary>
        ///
        private void ParseRule( )
        {
            // flag to incicate we are on consequent state
            bool consequent = false;

            // tokens like IF and THEN will be searched always in upper case
            string upRule = rule.ToUpper( );

            // the rule must start with IF, and must have a THEN somewhere
            if (!upRule.StartsWith("IF"))
            {
                throw new ArgumentException("A Fuzzy Rule must start with an IF statement.");
            }
            if (upRule.IndexOf("THEN") < 0)
            {
                throw new ArgumentException("Missing the consequent (THEN) statement.");
            }

            // building a list with all the expression (rule) string tokens
            string spacedRule = rule.Replace("(", " ( ").Replace(")", " ) ");

            // getting the tokens list
            string[] tokensList = GetRuleTokens(spacedRule);

            // stack to convert to RPN
            Stack <string> s = new Stack <string>( );
            // storing the last token
            string lastToken = "IF";
            // linguistic var read, used to build clause
            LinguisticVariable lingVar = null;

            // verifying each token
            for (int i = 0; i < tokensList.Length; i++)
            {
                // removing spaces
                string token = tokensList[i].Trim( );
                // getting upper case
                string upToken = token.ToUpper( );

                // ignoring these tokens
                if (upToken == "" || upToken == "IF")
                {
                    continue;
                }

                // if the THEN is found, the rule is now on consequent
                if (upToken == "THEN")
                {
                    lastToken  = upToken;
                    consequent = true;
                    continue;
                }

                // if we got a linguistic variable, an IS statement and a label is needed
                if (lastToken == "VAR")
                {
                    if (upToken == "IS")
                    {
                        lastToken = upToken;
                    }
                    else
                    {
                        throw new ArgumentException("An IS statement is expected after a linguistic variable.");
                    }
                }
                // if we got an IS statement, a label must follow it
                else if (lastToken == "IS")
                {
                    try
                    {
                        FuzzySet fs = lingVar.GetLabel(token);
                        Clause   c  = new Clause(lingVar, fs);
                        if (consequent)
                        {
                            output = c;
                        }
                        else
                        {
                            rpnTokenList.Add(c);
                        }
                        lastToken = "LAB";
                    }
                    catch (KeyNotFoundException)
                    {
                        throw new ArgumentException("Linguistic label " + token + " was not found on the variable " + lingVar.Name + ".");
                    }
                }
                // not VAR and not IS statement
                else
                {
                    // openning new scope
                    if (upToken == "(")
                    {
                        // if we are on consequent, only variables can be found
                        if (consequent)
                        {
                            throw new ArgumentException("Linguistic variable expected after a THEN statement.");
                        }
                        // if its a (, just push it
                        s.Push(upToken);
                        lastToken = upToken;
                    }
                    // operators
                    else if (upToken == "AND" || upToken == "OR" || unaryOperators.IndexOf(upToken) >= 0)
                    {
                        // if we are on consequent, only variables can be found
                        if (consequent)
                        {
                            throw new ArgumentException("Linguistic variable expected after a THEN statement.");
                        }

                        // pop all the higher priority operators until the stack is empty
                        while ((s.Count > 0) && (Priority(s.Peek( )) > Priority(upToken)))
                        {
                            rpnTokenList.Add(s.Pop( ));
                        }

                        // pushing the operator
                        s.Push(upToken);
                        lastToken = upToken;
                    }
                    // closing the scope
                    else if (upToken == ")")
                    {
                        // if we are on consequent, only variables can be found
                        if (consequent)
                        {
                            throw new ArgumentException("Linguistic variable expected after a THEN statement.");
                        }

                        // if there is nothing on the stack, an oppening parenthesis is missing.
                        if (s.Count == 0)
                        {
                            throw new ArgumentException("Openning parenthesis missing.");
                        }

                        // pop the tokens and copy to output until openning is found
                        while (s.Peek( ) != "(")
                        {
                            rpnTokenList.Add(s.Pop( ));
                            if (s.Count == 0)
                            {
                                throw new ArgumentException("Openning parenthesis missing.");
                            }
                        }
                        s.Pop( );

                        // saving last token...
                        lastToken = upToken;
                    }
                    // finally, the token is a variable
                    else
                    {
                        // find the variable
                        try
                        {
                            lingVar   = database.GetVariable(token);
                            lastToken = "VAR";
                        }
                        catch (KeyNotFoundException)
                        {
                            throw new ArgumentException("Linguistic variable " + token + " was not found on the database.");
                        }
                    }
                }
            }

            // popping all operators left in stack
            while (s.Count > 0)
            {
                rpnTokenList.Add(s.Pop( ));
            }
        }