This class provides the means to evaluate continued fractions (1). To create a continued fraction, authors subclass this class and provided concrete a and b coefficient methods.

For example, this is the continued fraction for the exponential function defined by (2):

 ContinuedFraction exponential = new ContinuedFraction() {
     public double getA(int n, double x) {
         if (n == 0) {
             return 1.0;
         } else if (n % 2 == 0) { // even
             return 2.0;
         } else { // odd
             return n;
         }
     }
    
     public double getB(int n, double x) {
         if (n % 2 == 0) { // even
             return x;
         } else { // odd
             return -x;
         }
 }
 

References:

1. Eric W. Weisstein. "Continued Fraction." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/ContinuedFraction.html
2. Exponential Function: Continued Fraction Representation. http://functions.wolfram.com/01.03.10.0001.01