Verhulst.java

Below is the syntax highlighted version of Verhulst.java from §9.1 Scientific Computation.

/******************************************************************************
 *  Compilation:  javac Verhulst.java
 *  Execution:    java Verhulst R
 *
 *  % java Verhulst 3.0
 *
 ******************************************************************************/

import java.text.DecimalFormat;

public class Verhulst {

    public static void main(String[] args) {
        DecimalFormat f = new DecimalFormat("0.0000000000");
        double R = Double.parseDouble(args[0]);
        int N = 100;
        double a, b, c, d, e;

        a = b = c = d = e = 0.5;

        for (int i = 1; i <= N; i++) {
            a = (R+1)*a - R*(a*a);
            b = (R+1)*b - (R*b)*b;
            c = ((R+1) - R*c) * c;
            d = R*d + (1 - R*d)*d;
            e = e + R*(e - e*e);
            if (i % 10 != 0) continue;
            StdOut.print(i + ":  ");
            StdOut.println(f.format(a) + "   " +
                               f.format(b) + "   " +
                               f.format(c) + "   " +
                               f.format(d) + "   " +
                               f.format(e));
        }
   }

}