neuron.java

神经网络源代码,实现了一个BP神经网络,可以完成基于BP的神经网络算法.

package net.openai.ai.nn.network;

import java.util.*;
import java.io.*;

public class Neuron implements Serializable {

    //  the collection of connections for this neuron
    private Vector connections = null;

    //  the collection of 'to' connections
    private Vector connectionsTo = null;

    //  the collection of 'from' connections
    private Vector connectionsFrom = null;

    //  the input for this neuron
    private double input = 0;

    //  the output for this neuron
    private double output = 0;

    //  the error of this neuron
    private double error = 0;

    //  a flag to tell whther this neuron has had it's error set
    private boolean errorSet = false;

    public Neuron() {
	connections = new Vector();
	connectionsTo = new Vector();
	connectionsFrom = new Vector();
    }

    /**
     * Gets the input for this neuron.
     *
     * @return double The input for this neuron.
     */
    public final double getInput() {
	return input;
    }

    /** 
     * Sets the input for this neuron.
     *
     * @param input The input to be set for this neuron.
     */
    public final void setInput(double input) {
	this.input = input;
	errorSet = false;
    }

    /**
     * Gets the output for this neuron.
     *
     * @return double The output for this neuron.
     */
    public final double getOutput() {
	return output;
    }

    /** 
     * Sets the output for this neuron.
     *
     * @param output The output to be set for this neuron.
     */
    public final void setOutput(double output) {
	this.output = output;
    }

    /**
     *
     * Gets a connection to a particular neuron.
     * @param neuron The neuron which may be connected to this neuron.
     * @return Connection to the neuron...or null if not connected.
     */
    public final Connection getConnectionTo(Neuron neuron) {
	//  make sure we have connections at all
	if(connections == null || connections.isEmpty())
	    return null;
	int size = connections.size();
	for(int i = 0; i < size; i++) {
	    Connection connection = (Connection) connections.elementAt(i);
	    if(neuron == connection.getToNeuron())
		return connection;
	}
	return null;
    }

    /**
     *
     * Gets all connections for this neuron..
     * @return Vector All connections for this neuron.
     */
    public final Vector getConnections() {
	return connections;
    }

    /**
     *
     * Gets all 'to' connections for this neuron..
     * @return Vector All connections 'to' this neuron.
     */
    public final Vector getConnectionsTo() {
	return connectionsTo;
    }

    /**
     *
     * Gets all 'from' connections for this neuron..
     * @return Vector All connections 'from' this neuron.
     */
    public final Vector getConnectionsFrom() {
	return connectionsFrom;
    }

    /**
     *
     * Add a connection from this neuron.
     * @param connection The connection to add.
     */
    public final void addConnectionFrom(Connection connection) {
	if(connection != null) {
	    connection.setFromNeuron(this);
	    connections.add(connection);
	    connectionsFrom.add(connection);
	} else {
	    //  throw some specialized error.
	}
    }

    /** 
     * 
     * Add a connection to this neuron. 
     * @param connection The connection to add. 
     */ 
    public final void addConnectionTo(Connection connection) { 
        if(connection != null) { 
            connection.setToNeuron(this); 
            connections.add(connection); 
	    connectionsTo.add(connection);
        } else { 
            //  throw some specialized error. 
        } 
    }

    /**
     * Gets the error for this neuron.
     *
     * @return double The error for this neuron.
     */
    public final double getError() {
	return error;
    }

    /** 
     * Sets the error for this neuron.
     *
     * @param error The error to be set for this neuron.
     */
    public final void setError(double error) {
	this.error = error;
	errorSet = true;
    }

    /** 
     * Returns a flag that tells whether this neuron has had the error
     * set
     *
     * @return boolean - Whether this neuron has had it's error calculated.
     */
    public final boolean isErrorSet() {
	return errorSet;
    }

    /**
     * Returns a string rpresentation of the neuron.
     *
     * @return String A representation of the neuron.
     */
    public final String toString() {
	String neuron = ("\nInput: " + input 
			 + "\nOutput: " + output
			 + "\nError: " + error);
	return neuron;
    }
    
}