public virtual void TestSingletonConcatenate() { Automaton singleton = BasicAutomata.MakeString("prefix"); Automaton expandedSingleton = singleton.CloneExpanded(); Automaton other = BasicAutomata.MakeCharRange('5', '7'); Automaton concat = BasicOperations.Concatenate(singleton, other); Assert.IsTrue(concat.IsDeterministic); Assert.IsTrue(BasicOperations.SameLanguage(BasicOperations.Concatenate(expandedSingleton, other), concat)); }
public virtual void TestSingletonNFAConcatenate() { Automaton singleton = BasicAutomata.MakeString("prefix"); Automaton expandedSingleton = singleton.CloneExpanded(); // an NFA (two transitions for 't' from initial state) Automaton nfa = BasicOperations.Union(BasicAutomata.MakeString("this"), BasicAutomata.MakeString("three")); Automaton concat = BasicOperations.Concatenate(singleton, nfa); Assert.IsFalse(concat.IsDeterministic); Assert.IsTrue(BasicOperations.SameLanguage(BasicOperations.Concatenate(expandedSingleton, nfa), concat)); }
private static Automaton NaiveUnion(IList <BytesRef> strings) { Automaton[] eachIndividual = new Automaton[strings.Count]; int i = 0; foreach (BytesRef bref in strings) { eachIndividual[i++] = BasicAutomata.MakeString(bref.Utf8ToString()); } return(BasicOperations.Union(eachIndividual)); }
public virtual void TestSingleton() { Automaton singleton = BasicAutomata.MakeString("foobar"); Automaton expandedSingleton = singleton.CloneExpanded(); Assert.IsTrue(BasicOperations.SameLanguage(singleton, expandedSingleton)); singleton = BasicAutomata.MakeString("\ud801\udc1c"); expandedSingleton = singleton.CloneExpanded(); Assert.IsTrue(BasicOperations.SameLanguage(singleton, expandedSingleton)); }
/// <summary> /// Builds a DFA for some string, and checks all Lev automata /// up to some maximum distance. /// </summary> private void AssertLev(string s, int maxDistance) { LevenshteinAutomata builder = new LevenshteinAutomata(s, false); LevenshteinAutomata tbuilder = new LevenshteinAutomata(s, true); Automaton[] automata = new Automaton[maxDistance + 1]; Automaton[] tautomata = new Automaton[maxDistance + 1]; for (int n = 0; n < automata.Length; n++) { automata[n] = builder.ToAutomaton(n); tautomata[n] = tbuilder.ToAutomaton(n); Assert.IsNotNull(automata[n]); Assert.IsNotNull(tautomata[n]); Assert.IsTrue(automata[n].Deterministic); Assert.IsTrue(tautomata[n].Deterministic); Assert.IsTrue(SpecialOperations.IsFinite(automata[n])); Assert.IsTrue(SpecialOperations.IsFinite(tautomata[n])); AutomatonTestUtil.AssertNoDetachedStates(automata[n]); AutomatonTestUtil.AssertNoDetachedStates(tautomata[n]); // check that the dfa for n-1 accepts a subset of the dfa for n if (n > 0) { Assert.IsTrue(automata[n - 1].SubsetOf(automata[n])); Assert.IsTrue(automata[n - 1].SubsetOf(tautomata[n])); Assert.IsTrue(tautomata[n - 1].SubsetOf(automata[n])); Assert.IsTrue(tautomata[n - 1].SubsetOf(tautomata[n])); Assert.AreNotSame(automata[n - 1], automata[n]); } // check that Lev(N) is a subset of LevT(N) Assert.IsTrue(automata[n].SubsetOf(tautomata[n])); // special checks for specific n switch (n) { case 0: // easy, matches the string itself Assert.IsTrue(BasicOperations.SameLanguage(BasicAutomata.MakeString(s), automata[0])); Assert.IsTrue(BasicOperations.SameLanguage(BasicAutomata.MakeString(s), tautomata[0])); break; case 1: // generate a lev1 naively, and check the accepted lang is the same. Assert.IsTrue(BasicOperations.SameLanguage(NaiveLev1(s), automata[1])); Assert.IsTrue(BasicOperations.SameLanguage(NaiveLev1T(s), tautomata[1])); break; default: AssertBruteForce(s, automata[n], n); AssertBruteForceT(s, tautomata[n], n); break; } } }
/// <summary> /// Return an automaton that accepts all 1-character insertions, deletions, and /// substitutions of s. /// </summary> private Automaton NaiveLev1(string s) { Automaton a = BasicAutomata.MakeString(s); a = BasicOperations.Union(a, InsertionsOf(s)); MinimizationOperations.Minimize(a); a = BasicOperations.Union(a, DeletionsOf(s)); MinimizationOperations.Minimize(a); a = BasicOperations.Union(a, SubstitutionsOf(s)); MinimizationOperations.Minimize(a); return(a); }
public virtual void TestFiniteStrings() { Automaton a = BasicOperations.Union(BasicAutomata.MakeString("dog"), BasicAutomata.MakeString("duck")); MinimizationOperations.Minimize(a); ISet <Int32sRef> strings = SpecialOperations.GetFiniteStrings(a, -1); Assert.AreEqual(2, strings.Count); Int32sRef dog = new Int32sRef(); Util.ToInt32sRef(new BytesRef("dog"), dog); Assert.IsTrue(strings.Contains(dog)); Int32sRef duck = new Int32sRef(); Util.ToInt32sRef(new BytesRef("duck"), duck); Assert.IsTrue(strings.Contains(duck)); }
/// <summary> /// Return an automaton that accepts all 1-character substitutions of s /// (replacing one character) /// </summary> private Automaton SubstitutionsOf(string s) { IList <Automaton> list = new List <Automaton>(); for (int i = 0; i < s.Length; i++) { Automaton au = BasicAutomata.MakeString(s.Substring(0, i)); au = BasicOperations.Concatenate(au, BasicAutomata.MakeAnyChar()); au = BasicOperations.Concatenate(au, BasicAutomata.MakeString(s.Substring(i + 1))); list.Add(au); } Automaton a = BasicOperations.Union(list); MinimizationOperations.Minimize(a); return(a); }
public void TestLexicon() { int num = AtLeast(1); for (int i = 0; i < num; i++) { automata.Clear(); terms.Clear(); for (int j = 0; j < 5000; j++) { string randomString = TestUtil.RandomUnicodeString(Random()); terms.Add(randomString); automata.Add(BasicAutomata.MakeString(randomString)); } AssertLexicon(); } }
/// <summary> /// Returns an automaton that accepts the concatenation of the languages of the /// given automata. /// <para/> /// Complexity: linear in number of states. /// </summary> public static Automaton Concatenate(Automaton a1, Automaton a2) { if (a1.IsSingleton && a2.IsSingleton) { return(BasicAutomata.MakeString(a1.singleton + a2.singleton)); } if (IsEmpty(a1) || IsEmpty(a2)) { return(BasicAutomata.MakeEmpty()); } // adding epsilon transitions with the NFA concatenation algorithm // in this case always produces a resulting DFA, preventing expensive // redundant determinize() calls for this common case. bool deterministic = a1.IsSingleton && a2.IsDeterministic; if (a1 == a2) { a1 = a1.CloneExpanded(); a2 = a2.CloneExpanded(); } else { a1 = a1.CloneExpandedIfRequired(); a2 = a2.CloneExpandedIfRequired(); } foreach (State s in a1.GetAcceptStates()) { s.accept = false; s.AddEpsilon(a2.initial); } a1.deterministic = deterministic; //a1.clearHashCode(); a1.ClearNumberedStates(); a1.CheckMinimizeAlways(); return(a1); }
public CompiledAutomaton(Automaton automaton, bool?finite, bool simplify) { if (simplify) { // Test whether the automaton is a "simple" form and // if so, don't create a runAutomaton. Note that on a // large automaton these tests could be costly: if (BasicOperations.IsEmpty(automaton)) { // matches nothing Type = AUTOMATON_TYPE.NONE; Term = null; CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } else if (BasicOperations.IsTotal(automaton)) { // matches all possible strings Type = AUTOMATON_TYPE.ALL; Term = null; CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } else { string commonPrefix; string singleton; if (automaton.Singleton == null) { commonPrefix = SpecialOperations.GetCommonPrefix(automaton); if (commonPrefix.Length > 0 && BasicOperations.SameLanguage(automaton, BasicAutomata.MakeString(commonPrefix))) { singleton = commonPrefix; } else { singleton = null; } } else { commonPrefix = null; singleton = automaton.Singleton; } if (singleton != null) { // matches a fixed string in singleton or expanded // representation Type = AUTOMATON_TYPE.SINGLE; Term = new BytesRef(singleton); CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } else if (BasicOperations.SameLanguage(automaton, BasicOperations.Concatenate(BasicAutomata.MakeString(commonPrefix), BasicAutomata.MakeAnyString()))) { // matches a constant prefix Type = AUTOMATON_TYPE.PREFIX; Term = new BytesRef(commonPrefix); CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } } } Type = AUTOMATON_TYPE.NORMAL; Term = null; if (finite == null) { this.Finite = SpecialOperations.IsFinite(automaton); } else { this.Finite = finite; } Automaton utf8 = (new UTF32ToUTF8()).Convert(automaton); if (this.Finite == true) { CommonSuffixRef = null; } else { CommonSuffixRef = SpecialOperations.GetCommonSuffixBytesRef(utf8); } RunAutomaton = new ByteRunAutomaton(utf8, true); sortedTransitions = utf8.GetSortedTransitions(); }
private Automaton ToAutomaton(IDictionary <string, Automaton> automata, IAutomatonProvider automaton_provider) { IList <Automaton> list; Automaton a = null; switch (kind) { case Kind.REGEXP_UNION: list = new List <Automaton>(); FindLeaves(exp1, Kind.REGEXP_UNION, list, automata, automaton_provider); FindLeaves(exp2, Kind.REGEXP_UNION, list, automata, automaton_provider); a = BasicOperations.Union(list); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_CONCATENATION: list = new List <Automaton>(); FindLeaves(exp1, Kind.REGEXP_CONCATENATION, list, automata, automaton_provider); FindLeaves(exp2, Kind.REGEXP_CONCATENATION, list, automata, automaton_provider); a = BasicOperations.Concatenate(list); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_INTERSECTION: a = exp1.ToAutomaton(automata, automaton_provider).Intersection(exp2.ToAutomaton(automata, automaton_provider)); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_OPTIONAL: a = exp1.ToAutomaton(automata, automaton_provider).Optional(); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_REPEAT: a = exp1.ToAutomaton(automata, automaton_provider).Repeat(); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_REPEAT_MIN: a = exp1.ToAutomaton(automata, automaton_provider).Repeat(min); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_REPEAT_MINMAX: a = exp1.ToAutomaton(automata, automaton_provider).Repeat(min, max); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_COMPLEMENT: a = exp1.ToAutomaton(automata, automaton_provider).Complement(); MinimizationOperations.Minimize(a); break; case Kind.REGEXP_CHAR: a = BasicAutomata.MakeChar(c); break; case Kind.REGEXP_CHAR_RANGE: a = BasicAutomata.MakeCharRange(from, to); break; case Kind.REGEXP_ANYCHAR: a = BasicAutomata.MakeAnyChar(); break; case Kind.REGEXP_EMPTY: a = BasicAutomata.MakeEmpty(); break; case Kind.REGEXP_STRING: a = BasicAutomata.MakeString(s); break; case Kind.REGEXP_ANYSTRING: a = BasicAutomata.MakeAnyString(); break; case Kind.REGEXP_AUTOMATON: Automaton aa = null; if (automata != null) { aa = automata[s]; } if (aa == null && automaton_provider != null) { try { aa = automaton_provider.GetAutomaton(s); } catch (Exception e) when(e.IsIOException()) { throw new ArgumentException(e.ToString(), e); } } if (aa == null) { throw new ArgumentException("'" + s + "' not found"); } a = (Automaton)aa.Clone(); // always clone here (ignore allow_mutate) break; case Kind.REGEXP_INTERVAL: a = BasicAutomata.MakeInterval(min, max, digits); break; } return(a); }
/// <summary> /// Returns an automaton that accepts the concatenation of the languages of the /// given automata. /// <para/> /// Complexity: linear in total number of states. /// </summary> public static Automaton Concatenate(IList <Automaton> l) { if (l.Count == 0) { return(BasicAutomata.MakeEmptyString()); } bool all_singleton = true; foreach (Automaton a in l) { if (!a.IsSingleton) { all_singleton = false; break; } } if (all_singleton) { StringBuilder b = new StringBuilder(); foreach (Automaton a in l) { b.Append(a.singleton); } return(BasicAutomata.MakeString(b.ToString())); } else { foreach (Automaton a in l) { if (BasicOperations.IsEmpty(a)) { return(BasicAutomata.MakeEmpty()); } } HashSet <int> ids = new HashSet <int>(); foreach (Automaton a in l) { ids.Add(a.GetHashCode()); } bool has_aliases = ids.Count != l.Count; Automaton b = l[0]; if (has_aliases) { b = b.CloneExpanded(); } else { b = b.CloneExpandedIfRequired(); } ISet <State> ac = b.GetAcceptStates(); bool first = true; foreach (Automaton a in l) { if (first) { first = false; } else { if (a.IsEmptyString) { continue; } Automaton aa = a; if (has_aliases) { aa = aa.CloneExpanded(); } else { aa = aa.CloneExpandedIfRequired(); } ISet <State> ns = aa.GetAcceptStates(); foreach (State s in ac) { s.accept = false; s.AddEpsilon(aa.initial); if (s.accept) { ns.Add(s); } } ac = ns; } } b.deterministic = false; //b.clearHashCode(); b.ClearNumberedStates(); b.CheckMinimizeAlways(); return(b); } }
/// <summary> /// Compute a DFA that accepts all strings within an edit distance of <paramref name="n"/>. /// <para> /// All automata have the following properties: /// <list type="bullet"> /// <item><description>They are deterministic (DFA).</description></item> /// <item><description>There are no transitions to dead states.</description></item> /// <item><description>They are not minimal (some transitions could be combined).</description></item> /// </list> /// </para> /// </summary> public virtual Automaton ToAutomaton(int n) { if (n == 0) { return(BasicAutomata.MakeString(word, 0, word.Length)); } if (n >= descriptions.Length) { return(null); } int range = 2 * n + 1; ParametricDescription description = descriptions[n]; // the number of states is based on the length of the word and n State[] states = new State[description.Count]; // create all states, and mark as accept states if appropriate for (int i = 0; i < states.Length; i++) { states[i] = new State(); states[i].number = i; states[i].Accept = description.IsAccept(i); } // create transitions from state to state for (int k = 0; k < states.Length; k++) { int xpos = description.GetPosition(k); if (xpos < 0) { continue; } int end = xpos + Math.Min(word.Length - xpos, range); for (int x = 0; x < alphabet.Length; x++) { int ch = alphabet[x]; // get the characteristic vector at this position wrt ch int cvec = GetVector(ch, xpos, end); int dest = description.Transition(k, xpos, cvec); if (dest >= 0) { states[k].AddTransition(new Transition(ch, states[dest])); } } // add transitions for all other chars in unicode // by definition, their characteristic vectors are always 0, // because they do not exist in the input string. int dest_ = description.Transition(k, xpos, 0); // by definition if (dest_ >= 0) { for (int r = 0; r < numRanges; r++) { states[k].AddTransition(new Transition(rangeLower[r], rangeUpper[r], states[dest_])); } } } Automaton a = new Automaton(states[0]); a.IsDeterministic = true; // we create some useless unconnected states, and its a net-win overall to remove these, // as well as to combine any adjacent transitions (it makes later algorithms more efficient). // so, while we could set our numberedStates here, its actually best not to, and instead to // force a traversal in reduce, pruning the unconnected states while we combine adjacent transitions. //a.setNumberedStates(states); a.Reduce(); // we need not trim transitions to dead states, as they are not created. //a.restoreInvariant(); return(a); }