package neuralnets;
/**
 * 
 * @author Dustin Stevens-baier
 * 
 * original code implementation from Ahmed Koshok 2004
 *
 */

import java.util.Random;
import java.util.ArrayList;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.File;
import java.util.Iterator;

public class KWTA
{
	private static int N=20; //the number of nodes
	private double m=0.0; // the minimum activation
	private double M=1.0; // the maximum activiation
	private double [][]W;
	private double []a;
	private double []updatedActivation;
	private double threshold = 0.1; //activation must be within .01 of the max or min
	private double approxMax;
	private double approxMin;
	private boolean converged;
	

	public KWTA()
	{
		W = new double[N][N];
		a = new double[N];
		updatedActivation = new double[N];
		buildConnectionStrengthMatrix();
		this.approxMax = M - threshold;
		this.approxMin = m + threshold;
	}
	
	static int getN()
	{
		return N;
	}
	
	private void buildConnectionStrengthMatrix()
	{
		for (int i=0; i<N; i++)
		{
			for (int j=0; j<N; j++)
			{
				if (i==j)
					W[i][j]=0;
				else
					W[i][j]=-1;
			}
		}
	}
	
	//Randomly initialize the activations
	private void initializeActivations()
	{
		Random generator = new Random();
		for (int i=0; i<N; i++)
		{
			double randDbl = generator.nextDouble();
			a[i] = m + randDbl*(M-m);
		}
	}
	
	//Initialize all activations with the same random value
	private void initializeIdenticalActivations()
	{
		Random generator = new Random();
		double randDbl = generator.nextDouble();
		for (int i=0; i<N; i++)
			a[i] = m + randDbl*(M-m);
	}
	
	public void simulate( double step, double ext, KWTAData kData)
	{
		double netInput;
		int counter = 0; 
//?????????????????Comment out to generate identical activations
		initializeActivations();
//?????????????????Uncomment below to generate identical activations
//		initializeIdenticalActivations();
//		???????????????????????????????????	
		kData.setInitialActivations(a);
		do

		{
			converged = true;
			counter++;
			//update the activations
			for(int i=0; i<N; i++)
			{
				netInput = 0;
				for (int j=0; j<N; j++)
				{
					netInput += a[j] * W[i][j];
				}
				netInput += ext;
				updatedActivation[i] = a[i] + step*(M -a[i])*(a[i] - m)*netInput;
			}
			//determine the convergence
			for (int i=0; i<N; i++)
			{
				a[i] = updatedActivation[i];
				if ((a[i] > this.approxMax) || (a[i] < this.approxMin) )
					converged = converged & true;
				else
					converged = false;		
			}
			kData.addEnergyData(counter, energyFunction( ext));
		}
		while (converged == false);
		kData.setFinalActivations(a);
	}
	
	//Calculate the energy
	private double energyFunction( double ext)
	{
		double sum1 = 0;
		double sum2 = 0;
		double energy = 0;
		for (int i=0; i<N; i++)
		{
			for (int j=0; j<N; j++)
			{
				sum1 += a[i]*W[i][j]*a[j];
			}
			sum2 += a[i]* ext;
		}
		energy = (-0.5)*sum1 - sum2;
		return energy;
	}

	//The main driver of the KWTA simulation
	public static void main(String[] args) {
		ArrayList alist = new ArrayList();
		double []ext = {0.5, 1.5, 2.5};
		double []steps = new double[4];
		steps[0] = (0.1)*(double)(1.0/(double)KWTA.getN());
		steps[1] = (0.5)*(double)(1.0/(double)KWTA.getN());
		steps[2] = (1.0)*(double)(1.0/(double)KWTA.getN());
		steps[3] = (2.0)*(double)(1.0/(double)KWTA.getN());

		KWTA kwta = new KWTA();

//???????????????Uncomment below for identical activation test		

	KWTAData kData = new KWTAData(steps[1], 2, ext[0], 1);
		alist.add(kData);
		kwta.simulate( steps[1], ext[0], kData);
		kData.writeEnergyToFile();
		String filename = "c:\\activations2.txt";
//?????????????????????????????????????????????????????????



//???????????????Comment out below for identical activation test
	//	for (int i=0; i < steps.length; i++)
		//{
		//	for (int j=0; j < ext.length; j++)
		//	{
		//		KWTAData kData= new KWTAData(steps[i], i+1, ext[j], j+1);
		//		alist.add(kData);
		//		kwta.simulate( steps[i], ext[j], kData);;
		//		kData.writeEnergyToFile();
		//	}
		//}
		//String filename = "c:\\activations.txt";
//??????????????????????????????????????????????????????????
				try
		{
			BufferedWriter out = new BufferedWriter(new FileWriter(new File(filename)));
			for (Iterator i = alist.iterator(); i.hasNext();)
			{
				KWTAData kdata = (KWTAData)i.next();
				out.write(kdata.toString());
			}
			out.close();
		}
		catch(IOException e){
			e.printStackTrace();
		}
	}
}