www.pudn.com > 基于VC的神经网络开发程序包(源码).rar > RecurrentNeuron.h

#ifndef _RECURRENTNEURON_H 
#define _RECURRENTNEURON_H 
 
#include "SimpleNeuron.h" 
#include "defines.h" 
#include  
 
namespace annie 
{ 
 
/** A neuron used for recurrent networks. 
  * These neurons have a concept of time. Thus, their output starts from an initial  
  * state and then as time progresses their output may change. 
  * 
  * Recurrent networks allow cycles in the graph formed by connections between 
  * neurons, which are not allowed by simple multi-layer networks. For example, 
  * consider a network in which a recurrent neuron is connected to itself. 
  * Output now becomes time dependent. 
  * output(time=0) = an initial, fixed value. 
  * output(time=1) = weight_of_link * output(0) 
  * output(time=t) = weight_of_link * output(t-1) etc. 
  * 
  * A recurrent neuron has all the features of a simple neuron and adds the concept 
  * of time, hence the RecurrentNeuron class is a sub-class of the SimpleNeuron class 
  */ 
class RecurrentNeuron : public SimpleNeuron 
{ 
protected: 
	/// Keeps track of the "time", i.e., number of steps taken by this neuron since the last reset 
	int _time; 
 
	/// The output of the neuron at time 0 
	real _initialOutput; 
 
	/// The last output of the neuron 
	real _lastOutput; 
 
	virtual void _recacheOutput(); 
public: 
	/** Creates a recurrent neuron. 
	  * The default initial value is 0, thus at time=0 the output 
	  * of the neuron will be 0. To change use reset 
	  * @param label The label to give to the neuron 
	  * @param hasBias Allow this neuron to have a bias? 
	  * @see reset 
	  */ 
	RecurrentNeuron(int label, bool hasBias=false); 
 
	/** Updates the time in the neuron by one unit. 
	  * This updation will ensure that all other neurons providing input to this 
	  * one (directly by a connection or indirectly through a series of connections) 
	  * also are brought up to date with the current time 
	  */ 
	virtual void step(); 
 
	/** Steps the neuron in time and returns the next output. 
	  * @see step 
	  * @see getOutput 
	  * @see getTime 
	  * @return The output of the neuron at the next time step 
	  */ 
	virtual real getNextOutput(); 
 
	/** Returns the output of the neuron. At time 0 this will be  
	  * the initial value which is set using reset(), and which is 
	  * zero by default. At other times the output will be calculated 
	  * @return the output of this neuron at the current time 
	  * @see getTime 
	  */ 
	virtual real getOutput(); 
 
	/// The output of the neuron at the previous time step.  
	virtual real getLastOutput(); 
 
	/// Returns "RecurrentNeuron" 
	virtual const char* getClassName(); 
 
	/** Returns the current time as known by the neuron. Initially 0, this 
	  * value can change by calls to step and getNextOutput 
	  * @see step 
	  * @see getNextOutput 
	  */ 
	virtual int getTime(); 
 
	/** Resets the time to 0. 
	  * @param initialActivation The activation of the neuron at time 0. The output at time 0 
	  *							 will be the activatation function applied on this value 
	  */ 
	virtual void reset(real initialActivation); 
 
	/// Not yet implemented 
	virtual void calculateNewWeights(real learningRate); 
 
	/// Not yet implemented 
	virtual void update(); 
 
	/// Not yet implemented 
	virtual void setDesiredOutput(real desired); 
}; 
 
}; //namespace annie 
#endif // define _RECURRENTNEURON_H