/* S0710.java
 *        ショットノイズのシミュレーション  
 *         (C) H.Ishikawa 2008 
 */
package simulation;

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import window.Window;

public class S0710 extends Applet implements ActionListener {
	Button button0;
	Button button1;
	boolean sw = false;
	public void init() {
		button0 = new Button(" 実行 ");
		button1 = new Button("クリア");
		add(button0);
		add(button1);
		button0.addActionListener(this);
		button1.addActionListener(this);
	}
	public void actionPerformed(ActionEvent e) {
		String label = e.getActionCommand();
		if (label.equals(" 実行 "))
			sw = true;
		else
			sw = false;
		repaint();
	}
	public void paint(Graphics g) {
		Window w;
		w = new Window();
		int height;
		int width;
		int SPACE = 30;
		int T_END = 1000000;
		double P = 0.01;
		int P_WIDTH = 10000;   /* パルス幅 */

		int t, tt;
		int i[] = new int[T_END]; /* 電流 */
		int f[] = new int[150];   /* ヒストグラム */
		double x = 0.0;
		double x2 = 0.0;
		int n = 0;
		int ii, j;

		/* スクリーンの大きさを読み取る */
		width = getSize().width;
		height = getSize().height;

		/* グラフィックの準備 */
		w.setWindow(0, 0.0, 0.0, (double) T_END, 150.0, SPACE, height - SPACE,
			width / 2, SPACE);
		w.axis(0, "t", T_END / 10, "i", 50.0, g);
		w.moveTo(0, 0.0, 0.0, g);
		w.setWindow(1, 0.0, 0.0, 0.1, 150.0, width / 2 + SPACE, height - SPACE,
			width - SPACE, SPACE);
		w.axis(1, "freq", 0.01, "i", 50, g);

		/* メイン */
		if (sw == true) {
			w.moveTo(1, 0.0, 0.0, g);

			for (t = 0; t < T_END; t++) {    //(1)
				if (P > Math.random()) {     //(2)
					for (tt = t; tt <= t + P_WIDTH; tt++) {
						if (tt < T_END) {
							i[tt] = i[tt] + 1;
						}
					}
				}
			}
			for (t = P_WIDTH; t < T_END; t++) {
				f[i[t]] = f[i[t]] + 1;       //(3)
				x = x + (double) i[t];
				x2 = x2 + (double) i[t] * (double) i[t];
				n = n + 1;
			}

			/* 表示 */
			for (t = 0; t < T_END; t++) {
				g.setColor(Color.green);
				w.lineTo(0, (double) t, (double) (i[t]), g);
			}

			for (ii = 0; ii < 150; ii++) {
				g.setColor(Color.blue);
				w.line(1, 0.0, (double) ii, (double) f[ii] / (double) n,
					(double) ii, g);
			}

			g.setColor(Color.black);
			g.drawString("mean = " + (x / (double) n) + "  var = "
					+ (x2 - x * x / (double) n) / (double) n, 10, height);
			stop();
		}
	}
}