// Copyright 2012 Georg-August-Universität Göttingen, Germany // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package de.ugoe.cs.autoquest.usageprofiles; import java.io.Serializable; import java.util.Collection; import java.util.List; import de.ugoe.cs.autoquest.eventcore.Event; /** *
* This interface defines the functionalities provided by stochastic processes. *
* * @author Steffen Herbold * @version 1.0 */ public interface IStochasticProcess extends Serializable { /** ** Returns the probability, that the next event is {@code symbol} given the last events are * {@code context}. The last element of {@code context} is the most recent in the history, the * first element is the oldest. *
* * @param context * recently observed symbols * @param symbol * event for which the probability is calculated * @return probabilty the {@code symbol} is the next event, given the last events * {@code context} * @throws IllegalArgumentException * thrown if context or symbol is null */ double getProbability(List* Returns the probabilitiy that a given sequence is generated by the stochastic process. *
* * @param sequence * sequences of which the probability is calculated * @return probability of the sequences; 1.0 if sequence is empty or null * @throws IllegalArgumentException * thrown if sequence is null */ double getProbability(List* Generates a random sequence of events. The sequence starts with {@link Event#STARTEVENT} and * finishes with {@link Event#ENDEVENT}. *
* * @return randomly generated sequence */ public List* Generates a random sequence of events. The sequence starts with {@link Event#STARTEVENT} and * finishes with *
* Generates all sequences of a given length are possible, i.e., have a positive probability.
* All states are used as possible starting states.
*
* Generates all sequences of given length that can are possible, i.e., have positive
* probability.
* If {@code fromStart==true}, all generated sequences start in {@link Event#STARTEVENT}.
* Otherwise this method is the same as {@link #generateSequences(int)}.
*
* Generates all sequences starting with {@link Event#STARTEVENT} and finishing with * {@link Event#ENDEVENT} of a given length. It is possible that no such sequence exists with * the defined length and the returned set is empty. If {@code length} is less than 2 the * returned set is always empty. *
* * @param length * @return generated sequences * @throws IllegalArgumentException * thrown if length is less than or equal to 0 */ public Collection* Returns the number of states known by the stochastic process, i.e., the size of its alphabet. *
* * @return number of states */ public int getNumSymbols(); /** ** Returns a string representation of all known states. *
* * @return string representation for all known states */ public String[] getSymbolStrings(); /** ** Returns the number of states the process would have if it would be flattened through * state-splitting to a first-order Markov model. *
** If it is not possible to flatten the model, -1 is returned. *
* * @return number of states an equivalent FOM would have; -1 if not available */ public int getNumFOMStates(); /** ** Returns the number of transitions the process would have if it would be flattened through * state-splitting to a first-order Markov model. *
* * @return number of transitions an equivalent FOM would have; -1 if not available */ public int getNumTransitions(); /** ** Returns all states known by the stochastic process, i.e., its {@link Event}s. *
* * @return events known by the process */ public Collection