!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);
  }
}