public DfaTransitionDiagram minimizeStates() { List <List <State> > pi = new List <List <State> >(); //initialize pi pi.Add(this.finalStates); List <State> temp = new List <State>(); //find non final states foreach (State s in this.states) { if (s.type == stateType.intermediate || s.type == stateType.initial) { temp.Add(s); } } if (temp.Count != 0) { pi.Add(temp); } //now pi has two sets: finals and non-finals if (pi.Count == 1) // i.e. pi has only one set because all the states are either final or both (initial & final) { MessageBox.Show("The diagram is already minimized"); return(this); } DfaTransitionDiagram newDiagram = new DfaTransitionDiagram(); newDiagram.inputs = this.inputs; newDiagram.noOfInputs = this.noOfInputs; newDiagram.setCanvas(canvasMain); List <List <State> > newPi = pi; // for the initial condition List <List <State> > set; while (true) { pi = newPi; set = pi; List <List <State> > piTemp = null; foreach (String input in inputs) { piTemp = new List <List <State> >(); foreach (List <State> ls in set) { if (ls.Count == 1) { //beacuse if a set contains only a single item then it will remain single piTemp.Add(new List <State>()); piTemp.Last().Add(ls[0]); continue; } List <int> abc = new List <int>(); foreach (State s in ls) { State stt = table[s.index, getIndexOfInput(input)]; if (stt == null) { MessageBox.Show("To minimize a DFA, For each State you must define transitions for all input symbols"); return(null); } else { abc.Add(piTemp.Count + getSetIndex(pi, stt)); } } //pitemp.count is added because before that it was problematic for the iteration //with the next set on same input symbol due to same 0 1 etc in abc for (int i = 0; i < abc.Count; i++) { piTemp.Add(new List <State>()); } while (piTemp.Count <= abc.Max()) { piTemp.Add(new List <State>()); } int j = 0; foreach (int i in abc) { piTemp[i].Add(ls[j]); j++; } // remove empty lists List <List <State> > t = new List <List <State> >(); // to bypass the collection modified error foreach (List <State> ls2 in piTemp) { if (ls2.Count == 0) { t.Add(ls2); } } foreach (List <State> ls2 in t) { piTemp.Remove(ls2); } } set = piTemp; } newPi = piTemp; if (isPiEqualsNewPi(pi, newPi)) { break; } } canvasMain.Children.Clear(); // now create a new diagram by taking states from pi foreach (List <State> ls in pi) { State s = newDiagram.addState(State.getNewStatePosition()); s.figure.ToolTip = getToolTip(ls); if (containsInitialState(ls)) { s.addStartingArrow(canvasMain); newDiagram.initialStates.Add(s); s.type = stateType.initial; if (containsFinalState(ls)) { s.type = stateType.both; newDiagram.finalStates.Add(s); s.figure.Stroke = Brushes.Black; s.figure.StrokeThickness = 2; } } else if (containsFinalState(ls)) { s.type = stateType.final; newDiagram.finalStates.Add(s); s.figure.Stroke = Brushes.Black; s.figure.StrokeThickness = 2; } } foreach (List <State> ls in pi) { State source = ls[0]; foreach (string input in newDiagram.inputs) { State dest = table[ls[0].index, getIndexOfInput(input)]; if (dest != null) { source = getStateByToolTip(newDiagram, getToolTip(ls)); foreach (List <State> ls2 in pi) { if (ls2.Contains(dest)) { dest = getStateByToolTip(newDiagram, getToolTip(ls2)); break; } } if (source != null && dest != null) { Transition tr = newDiagram.addTransition(source, dest); if (tr != null) { ((ComboBox)((StackPanel)tr.figure.Tag).Children[0]).SelectedItem = input; } } } } } //code inserted later to patch the flaws in algorithm bool isDeletedSomeState = true; while (isDeletedSomeState) { isDeletedSomeState = false; bool isOrphanState; List <State> tmp = new List <State>(newDiagram.states); foreach (State s in tmp) { isOrphanState = true; bool hasSource = false, hasDest = false; foreach (Transition t in s.transitions) { if (s.type == stateType.initial || s.type == stateType.final || s.type == stateType.both) { isOrphanState = false; break; } if (t.destState.index == s.index) { hasDest = true; } if (t.sourceState.index == s.index) { hasSource = true; } if (hasSource && hasDest) { isOrphanState = false; break; } } if (isOrphanState) { newDiagram.selectedState = s; newDiagram.deleteState(); isDeletedSomeState = true; } } } return(newDiagram); }
public DfaTransitionDiagram convertToDfa() { NfaTransitionDiagram diagram = this.removeNullMoves(); DfaTransitionDiagram newDiagram = new DfaTransitionDiagram(); newDiagram.setCanvas(canvasMain); canvasMain.Children.Clear(); newDiagram.inputs = diagram.inputs; newDiagram.noOfInputs = diagram.noOfInputs; State.resetPoints(); // because the some state positions have been consumed by removeNullMoves(), so reset them //add the initial state State iState = newDiagram.addState(State.getNewStatePosition()); iState.addStartingArrow(canvasMain); iState.type = diagram.initialStates[0].type; newDiagram.initialStates.Add(iState); if (iState.type == stateType.both) { newDiagram.finalStates.Add(iState); iState.figure.Stroke = Brushes.Black; iState.figure.StrokeThickness = 2; } iState.figure.ToolTip = diagram.initialStates[0].figure.ToolTip; newDiagram.selectedState = iState; List <List <State> > newStates = new List <List <State> >(); List <State> temp = new List <State>(); temp.Add(iState); newStates.Add(temp); string tooltip; int i = -1; while (i < newStates.Count - 1) { List <State> currentState = newStates[++i]; newDiagram.selectedState = getStateByToolTip(newDiagram, getToolTip(currentState)); foreach (string input in newDiagram.inputs) { List <State> nextState = new List <State>(); foreach (State s in currentState) { if (diagram.table[s.index, diagram.getIndexOfInput(input)] != null) { foreach (State t in diagram.table[s.index, diagram.getIndexOfInput(input)]) { if (!nextState.Contains(t)) { nextState.Add(t); } } } } tooltip = getToolTip(nextState); if (tooltip != "") { State x = getStateByToolTip(newDiagram, tooltip); if (x == null) //nextState do not exists in the newStates or newDiagram.States { // a new state is found State s = newDiagram.addState(State.getNewStatePosition()); s.figure.ToolTip = tooltip; if (containsFinalState(nextState)) { s.type = stateType.final; newDiagram.finalStates.Add(s); s.figure.Stroke = Brushes.Black; s.figure.StrokeThickness = 2; } Point pt1 = new Point(); Random rnd = new Random(); pt1.X = (double)rnd.Next((int)canvasMain.ActualWidth); pt1.X = (double)rnd.Next((int)canvasMain.ActualHeight); Transition tr = newDiagram.addTransition(newDiagram.selectedState, s, pt1.ToString()); ((ComboBox)((StackPanel)tr.figure.Tag).Children[0]).SelectedItem = input; newStates.Add(nextState); } else { Transition tr = newDiagram.addTransition(newDiagram.selectedState, x); if (tr != null) { ((ComboBox)((StackPanel)tr.figure.Tag).Children[0]).SelectedItem = input; } } } } } return(newDiagram); }