getSymbolsIn() public method

public getSymbolsIn ( Sentence s ) : List
s AIMA.Core.Logic.Propositional.Parsing.Ast.Sentence
return List
Example #1
0
 public bool ttEntails(KnowledgeBase kb, String alpha)
 {
     Sentence kbSentence = kb.asSentence();
     Sentence querySentence = (Sentence)new PEParser().parse(alpha);
     SymbolCollector collector = new SymbolCollector();
     List<Symbol> kbSymbols = collector.getSymbolsIn(kbSentence);
     List<Symbol> querySymbols = collector.getSymbolsIn(querySentence);
     List<Symbol> symbols = SetOps.union(kbSymbols, querySymbols);
     List<Symbol> symbolList = symbols;
     return ttCheckAll(kbSentence, querySentence, symbolList, new Model());
 }
Example #2
0
        public Model findModelFor(String logicalSentence, int numberOfFlips,
                double probabilityOfRandomWalk)
        {
            myModel = new Model();
            Sentence s = (Sentence)new PEParser().parse(logicalSentence);
            CNFTransformer transformer = new CNFTransformer();
            CNFClauseGatherer clauseGatherer = new CNFClauseGatherer();
            SymbolCollector sc = new SymbolCollector();

            List<Symbol> symbols = sc.getSymbolsIn(s);
            Random r = new Random();
            for (int i = 0; i < symbols.Count; i++)
            {
                Symbol sym = (Symbol)symbols[i];
                myModel = myModel.extend(sym, Util.randombool());
            }
            List<Sentence> clauses = clauseGatherer.getClausesFrom(transformer
                            .transform(s));

            for (int i = 0; i < numberOfFlips; i++)
            {
                if (getNumberOfClausesSatisfiedIn(clauses, myModel) == clauses.Count)
                {
                    return myModel;
                }
                Sentence clause = clauses[random.Next(clauses.Count)];

                List<Symbol> symbolsInClause = sc
                        .getSymbolsIn(clause);
                if (random.NextDouble() >= probabilityOfRandomWalk)
                {
                    Symbol randomSymbol = symbolsInClause[random
                            .Next(symbolsInClause.Count)];
                    myModel = myModel.flip(randomSymbol);
                }
                else
                {
                    Symbol symbolToFlip = getSymbolWhoseFlipMaximisesSatisfiedClauses(
                            clauses,
                            symbolsInClause, myModel);
                    myModel = myModel.flip(symbolToFlip);
                }

            }
            return null;
        }