rationals.transformations

Class TransformationsToolBox

java.lang.Object

rationals.transformations.TransformationsToolBox

public class TransformationsToolBox
extends Object

A set of utility methods used in transformations of automaton.

Version:

$Id: TransformationsToolBox.java 10 2007-05-30 17:25:00Z oqube $

Author:

nono

Constructor Summary

Constructors

Constructor and Description
TransformationsToolBox()

Method Summary

Modifier and Type	Method and Description
static boolean	containsAnInitialState(Set<State> s)
static boolean	containsATerminalState(Set<State> s)
static Set<State>	epsilonClosure(Set<State> s, Automaton a) Compute the set of states that are reachable ina given automanton from a set of states using epsilon moves.
static Map<Object,Set<State>>	mapAlphabet(Set<Transition> ts, Automaton a) Compute a map from letters to set of states given a set of transitions.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransformationsToolBox

public TransformationsToolBox()

Method Detail

containsATerminalState

public static boolean containsATerminalState(Set<State> s)

Parameters:

s - s

Returns:

true if there is a terminal state in the input

containsAnInitialState

public static boolean containsAnInitialState(Set<State> s)

Parameters:

s - s

Returns:

true if there is an initial state in the input

epsilonClosure

public static Set<State> epsilonClosure(Set<State> s,
                                        Automaton a)

Compute the set of states that are reachable ina given automanton from a set of states using epsilon moves. An epsilon transition is a transition which is labelled null.

Parameters:

s - the set of starting states

a - the automaton

Returns:

a - possibly empty - set of states reachable from s through epsilon transitions.

mapAlphabet

public static Map<Object,Set<State>> mapAlphabet(Set<Transition> ts,
                                                 Automaton a)

Compute a map from letters to set of states given a set of transitions. This method computes the arrival set of states for each letter occuring in a given set of transitions. epsilon transitions are not taken into account.

Parameters:

ts - a Set of Transition objects.

a - a

Returns:

a Map from Object - transition labels - to Set of State objects.