// The Boltzmann Macihne: The Necker Cube Example
// 
// by Simon Dennis
//
// 20th December 1995
//

import java.awt.*;
import java.awt.Graphics;
import java.lang.Math;
import java.lang.Integer;

public class Necker extends java.applet.Applet {
    int    Gx;
    int    Gy;
    boolean    filled = true;
    int    a[] = {1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0};
    int    w[][] = 
        {{0, 2, 0, 2, 2, 0, 0, 0, -3, -3, 0, 0, 0, 0, 0, 0},
        {2, 0, 2, 0, 0, 2, 0, 0, -3, -3, 0, 0, 0, 0, 0, 0},
        {0, 2, 0, 2, 0, 0, 2, 0, 0, 0, -3, -3, 0, 0, 0, 0},
        {2, 0, 2, 0, 0, 0, 0, 2, 0, 0, -3, -3, 0, 0, 0, 0},
        {2, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, -3, -3, 0, 0},
        {0, 2, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, -3, -3, 0, 0},
        {0, 0, 2, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, -3, -3},
        {0, 0, 0, 2, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, -3, -3},
        {-3, -3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 2, 0, 0, 0},
        {-3, -3, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 2, 0, 0},
        {0, 0, -3, -3, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 2, 0},
        {0, 0, -3, -3, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 2},
        {0, 0, 0, 0, -3, -3, 0, 0, 2, 0, 0, 0, 0, 2, 0, 2},
        {0, 0, 0, 0, -3, -3, 0, 0, 0, 2, 0, 0, 2, 0, 2, 0},
        {0, 0, 0, 0, 0, 0, -3, -3, 0, 0, 2, 0, 0, 2, 0, 2},
        {0, 0, 0, 0, 0, 0, -3, -3, 0, 0, 0, 2, 2, 0, 2, 0}};
        
    int    x[] ={25, 50, 150, 125, 25, 50, 150, 125, 125, 150, 250, 225, 125, 150, 250, 225};
    int    y[] = {125, 100, 100, 125, 225, 200, 200, 225, 325, 300, 300, 325, 425, 400, 400, 425};

    int    connected[] = {0, 1, 0, 3, 0, 4, 1, 2, 2, 3, 2, 6, 3, 7, 4, 7, 6, 7, 8, 9, 8, 12, 9, 10, 9, 13, 10, 14, 12, 13, 12, 15, 13, 14, 14, 15};

    private Button OneB, TwentyB, ResetB;
    private Checkbox WeightsC;

    public void init() {
        resize(400,500);
        Panel p = new Panel();                // panel holds group of wigits
        Panel local = new Panel();
 
        local.setLayout(new GridLayout(2, 2, 20, 20));  //layout manger for panel
        OneB = new Button("Do 1 Iteration");
        local.add(OneB);
        TwentyB = new Button("Do 20 Iterations");
        local.add(TwentyB);
        ResetB = new Button("Reset");
        local.add(ResetB);
        WeightsC = new Checkbox("Weights visible?");
        local.add(WeightsC);

        p.add(local);
 
        add(p);
  
    }

    public void paint(Graphics g) {
        int    i;
        int    j;
        int    goodness;

        if (WeightsC.getState()){
            for (i=0; i<16; i++)
                for (j=0; j<16; j++)
                    if (w[i][j] > 0){
                        g.setColor(Color.blue);
                        g.drawLine(x[i]+10, y[i]+10, x[j]+10, y[j]+10);
                        }
                    else if (w[i][j] < 0){
                        g.setColor(Color.red);
                        g.drawLine(x[i]+10, y[i]+10, x[j]+10, y[j]+10);
                        }
            }
        else {
            for (i=0; i<35; i=i+2){
                g.setColor(Color.black);
                g.drawLine(x[connected[i]]+10, y[connected[i]]+10, x[connected[i+1]]+10, y[connected[i+1]]+10);
            };
        };

        g.setColor(Color.black);
        for (i=0; i< 16; i++)
            if (a[i] == 1){
                g.drawRect(x[i],y[i], 20, 20);
                g.clearRect(x[i]+1,y[i]+1, 19, 19);
                }
            else {
                g.fillRect(x[i],y[i], 20, 20);
            }
                
        goodness = 0;
        for (i=0; i<16; i++)
            for (j=0; j<16; j++)
                goodness = goodness + w[i][j] * a[i] * a[j];
        g.drawString("Goodness = " + Integer.toString(goodness), 225, 150);
    }

    public double    sigmoid(double x){
        return(1.0/(1+Math.exp(-x)));
    }

    public boolean action(Event evt, Object arg) {
        double    r;
        int    unit;
        float    netinput;
        int    i;
        int    NumberOfIterations, Iterations;
 
        NumberOfIterations = 1;
        if ("Do 1 Iteration".equals(arg)) 
            NumberOfIterations = 1;
        else if ("Do 20 Iterations".equals(arg))
            NumberOfIterations = 20;
        else if ("Reset".equals(arg)){
            for (i=0; i<16; i++)
            if (Math.random() < 0.5)
                a[i] = 0;
            else
                a[i] = 1;
            repaint();
            return(true);
        };

        for (Iterations=0; Iterations < NumberOfIterations; Iterations++){
            unit = (int) (Math.random() *16.0);
            netinput = 0;
            for (i=0; i<16; i++)
                netinput = netinput + a[i] * w[unit][i] ;
            r = Math.random();
            if (r < sigmoid((double)netinput))
                a[unit] = 1;
            else
                a[unit] = 0;
            };
        repaint();
        return(true);
    }
}