/****************************************************************************** * Compilation: javac IFS.java * Execution: java IFS trials < input.txt * Dependencies: StdDraw.java * * Here are some sample data files: * * https://introcs.cs.princeton.edu/java/22library/barnsley.txt * https://introcs.cs.princeton.edu/java/22library/binary.txt * https://introcs.cs.princeton.edu/java/22library/culcita.txt * https://introcs.cs.princeton.edu/java/22library/cyclosorus.txt * https://introcs.cs.princeton.edu/java/22library/dragon.txt * https://introcs.cs.princeton.edu/java/22library/fern-sedgewick.txt * https://introcs.cs.princeton.edu/java/22library/fishbone.txt * https://introcs.cs.princeton.edu/java/22library/floor.txt * https://introcs.cs.princeton.edu/java/22library/koch.txt * https://introcs.cs.princeton.edu/java/22library/sierpinski.txt * https://introcs.cs.princeton.edu/java/22library/spiral.txt * https://introcs.cs.princeton.edu/java/22library/swirl.txt * https://introcs.cs.princeton.edu/java/22library/tree.txt * https://introcs.cs.princeton.edu/java/22library/zigzag.txt * ******************************************************************************/ public class IFS { public static void main(String[] args) { // number of iterations int trials = Integer.parseInt(args[0]); // probability distribution for choosing each rule double[] dist = StdArrayIO.readDouble1D(); // update matrices double[][] cx = StdArrayIO.readDouble2D(); double[][] cy = StdArrayIO.readDouble2D(); // current value of (x, y) double x = 0.0, y = 0.0; // do trials iterations of the chaos game StdDraw.enableDoubleBuffering(); for (int t = 0; t < trials; t++) { // pick a random rule according to the probability distribution int r = StdRandom.discrete(dist); // do the update double x0 = cx[r][0]*x + cx[r][1]*y + cx[r][2]; double y0 = cy[r][0]*x + cy[r][1]*y + cy[r][2]; x = x0; y = y0; // draw the resulting point StdDraw.point(x, y); // for efficiency, display only every 100 iterations if (t % 100 == 0) { StdDraw.show(); StdDraw.pause(10); } } // ensure everything gets drawn StdDraw.show(); } }