/*
* Encog(tm) Core v3.3 - Java Version
* http://www.heatonresearch.com/encog/
* https://github.com/encog/encog-java-core
* Copyright 2008-2014 Heaton Research, Inc.
*
* 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.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package org.encog.ml.bayesian.parse;
import java.util.ArrayList;
import java.util.List;
import org.encog.ml.bayesian.BayesianError;
import org.encog.ml.bayesian.BayesianEvent;
import org.encog.ml.bayesian.BayesianNetwork;
/**
* A probability that has been parsed.
*/
public class ParsedProbability {
/**
* The base events.
*/
private final List<ParsedEvent> baseEvents = new ArrayList<ParsedEvent>();
/**
* The given events.
*/
private final List<ParsedEvent> givenEvents = new ArrayList<ParsedEvent>();
public void addGivenEvent(ParsedEvent event) {
this.givenEvents.add(event);
}
/**
* Add a base event.
* @param event The base event to add.
*/
public void addBaseEvent(ParsedEvent event) {
this.baseEvents.add(event);
}
/**
* Get the arguments to this event.
* @param network The network.
* @return The arguments.
*/
public int[] getArgs(BayesianNetwork network) {
int[] result = new int[givenEvents.size()];
for(int i=0;i<givenEvents.size();i++) {
ParsedEvent givenEvent = this.givenEvents.get(i);
BayesianEvent actualEvent = network.getEvent(givenEvent.getLabel());
result[i] = givenEvent.resolveValue(actualEvent);
}
return result;
}
/**
* @return The child events.
*/
public ParsedEvent getChildEvent() {
if( this.baseEvents.size()>1 ) {
throw new BayesianError("Only one base event may be used to define a probability, i.e. P(a), not P(a,b).");
}
if( this.baseEvents.size()==0) {
throw new BayesianError("At least one event must be provided, i.e. P() or P(|a,b,c) is not allowed.");
}
return this.baseEvents.get(0);
}
/**
* Define the truth table.
* @param network The bayesian network.
* @param result The resulting probability.
*/
public void defineTruthTable(BayesianNetwork network, double result) {
ParsedEvent childParsed = getChildEvent();
BayesianEvent childEvent = network.requireEvent(childParsed.getLabel());
// define truth table line
int[] args = getArgs(network);
childEvent.getTable().addLine(result, childParsed.resolveValue(childEvent), args);
}
/**
* @return The base events.
*/
public List<ParsedEvent> getBaseEvents() {
return baseEvents;
}
/**
* @return The given events.
*/
public List<ParsedEvent> getGivenEvents() {
return givenEvents;
}
/**
* Define the relationships.
* @param network The network.
*/
public void defineRelationships(BayesianNetwork network) {
// define event relations, if they are not there already
ParsedEvent childParsed = getChildEvent();
BayesianEvent childEvent = network.requireEvent(childParsed.getLabel());
for( ParsedEvent event : this.givenEvents) {
BayesianEvent parentEvent = network.requireEvent(event.getLabel());
network.createDependency(parentEvent, childEvent);
}
}
/**
* {@inheritDoc}
*/
public String toString() {
StringBuilder result = new StringBuilder();
result.append("[ParsedProbability:baseEvents=");
result.append(this.baseEvents.toString());
result.append(",givenEvents=");
result.append(this.givenEvents.toString());
result.append("]");
return result.toString();
}
}