!7

import javax.swing.Timer;

public class main extends JPanel {

  class Trainer {

      double[] inputs;

      int answer;

      Trainer(double x, double y, int a) {

          inputs = new double[]{x, y, 1};

          answer = a;

      }

  }

  Trainer[] training = new Trainer[2000];

  double[] weights;

  double c = 0.00001;

  int count;

  *(int n) {

      Random r = new Random();

      Dimension dim = new Dimension(640, 360);

      setPreferredSize(dim);

      setBackground(Color.white);

      weights = new double[n];

      for (int i = 0; i < weights.length; i++) {

          weights[i] = r.nextDouble() * 2 - 1;

      }

      for (int i = 0; i < training.length; i++) {

          double x = r.nextDouble() * dim.width;

          double y = r.nextDouble() * dim.height;

          int answer = y < f(x) ? -1 : 1;

          training[i] = new Trainer(x, y, answer);

      }

      new Timer(10, (ActionEvent e) -> {

          repaint();

      }).start();

  }

  private double f(double x) {

      return x * 0.7 + 40;

  }

  int feedForward(double[] inputs) {

      assert inputs.length == weights.length : "weights and input length mismatch";

      double sum = 0;

      for (int i = 0; i < weights.length; i++) {

          sum += inputs[i] * weights[i];

      }

      return activate(sum);

  }

  int activate(double s) {

      return s > 0 ? 1 : -1;

  }

  void train(double[] inputs, int desired) {

      int guess = feedForward(inputs);

      double error = desired - guess;

      for (int i = 0; i < weights.length; i++) {

          weights[i] += c * error * inputs[i];

      }

  }

  @Override

  public void paintComponent(Graphics gg) {

      super.paintComponent(gg);

      Graphics2D g = (Graphics2D) gg;

      g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

              RenderingHints.VALUE_ANTIALIAS_ON);

      // we're drawing upside down

      int x = getWidth();

      int y = (int) f(x);

      g.setStroke(new BasicStroke(2));

      g.setColor(Color.orange);

      g.drawLine(0, (int) f(0), x, y);

      train(training[count].inputs, training[count].answer);

      count = (count + 1) % training.length;

      g.setStroke(new BasicStroke(1));

      g.setColor(Color.black);

      for (int i = 0; i < count; i++) {

          int guess = feedForward(training[i].inputs);

          x = (int) training[i].inputs[0] - 4;

          y = (int) training[i].inputs[1] - 4;

          if (guess > 0)

              g.drawOval(x, y, 8, 8);

          else

              g.fillOval(x, y, 8, 8);

      }

  }

  p-awt {

    JFrame f = new JFrame();

    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    f.setTitle("Perceptron");

    f.setResizable(false);

    f.add(new main(3), BorderLayout.CENTER);

    f.pack();

    f.setLocationRelativeTo(null);

    f.setVisible(true);

  }

}