/* From: "COMPUTATIONAL PHYSICS, 2nd Ed" 
   by RH Landau, MJ Paez, and CC Bordeianu 
   Copyright Wiley-VCH, 2007.
   Electronic Materials copyright: R Landau, Oregon State Univ, 2007;
   MJ Paez, Univ Antioquia, 2007; and CC Bordeianu, Univ Bucharest, 2007.
   Support by National Science Foundation                          
*/
// SIERPIN.java: gasket statistical simulation

import java.io.*;                          // Location of PrintWriter
import java.util.*;                             // Location of Random
import java.lang.*;                               // Location of Math

public class SIERPIN    {
  
  public static void main(String[] argv) 
                          throws IOException, FileNotFoundException {
	  PrintWriter q = new PrintWriter(
			                     new FileOutputStream("SIERPIN.DAT"),true);

	              	// Initialize 48 bit pseudo-random number generator
	  long seed = 899432;         // Different seed, different sequence
	  Random randnum = new Random(seed); 
    int imax = 29999, i = 0;
	  double a1 = 20.0, b1 = 20.0;                         // vertex #1
	  double a2 = 320.0, b2 = 20.0;                        // vertex #2
	  double a3 = 170.0, b3 = 280.0;                       // vertex #3
	  double x = 180.0, y = 150.0, r = 0.0;
	
	  for ( i = 1; i <= imax; i++ )  {
		  r = randnum.nextDouble();
	    if ( r <= 0.333333333333333)	{
			  x = 0.5*(x+a1);
			  y = 0.5*(y+b1);
			}
      else if ( r > 0.333333333333333 && r <= 0.666666666666666)	{
			  x = 0.5 * (x+a2);
			  y = 0.5 * (y+b2);
			}
      else  {
			  x = 0.5*(x+a3);
			  y = 0.5*(y+b3);
			}
      q.println(x+"  "+y);
    }
    System.out.println(" ");
	  System.out.println("SIERPIN Program Complete.");
	  System.out.println("Data stored in SIERPIN.DAT");
	  System.out.println(" ");
	  System.out.println(" ");
	  System.out.println(" ");
	  System.out.println(" ");
  }
}                                                     // End of class