/* 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; & CC Bordeianu, Univ Bucharest, 2007
   Support by National Science Foundation                              
*/                                   
//  bugs.c: Bifurcation diagram for logistic map
//   comment: plot without conneting datapoints with lines      

#include<stdio.h>

#define m_min 0.0                                    // minimum for m
#define m_max 4.0                                    // maximum for m
#define step 0.01                                   // stepsize for m

main() {
	
   double m, y;
   int i;
   
   FILE *output;                             // save data in bugs.dat
   output = fopen("bugs.dat","w");
   
   for (m=m_min; m<=m_max; m+=step)  {                  // loop for m
      y = 0.5;                            // arbitrary starting value
			                                           // ignore transients
      for (i=1; i<=200; i++)  y = m*y*(1-y);  
			                                      // then record 200 points
      for (i=201; i<=401; i++) {            
         y = m*y*(1-y);
         fprintf(output, "%.4f\t%.4f\n", m, y);
      }
   }
   printf("data stored in bugs.dat.\n");
   fclose(output);
}