public static Fraction getFraction()

in src/main/java/org/apache/commons/lang3/math/Fraction.java [246:292]

• 46 lines of code
• 8 McCabe index (conditional complexity)

    public static Fraction getFraction(double value) {
        final int sign = value < 0 ? -1 : 1;
        value = Math.abs(value);
        if (value > Integer.MAX_VALUE || Double.isNaN(value)) {
            throw new ArithmeticException("The value must not be greater than Integer.MAX_VALUE or NaN");
        }
        final int wholeNumber = (int) value;
        value -= wholeNumber;

        int numer0 = 0; // the pre-previous
        int denom0 = 1; // the pre-previous
        int numer1 = 1; // the previous
        int denom1 = 0; // the previous
        int numer2; // the current, setup in calculation
        int denom2; // the current, setup in calculation
        int a1 = (int) value;
        int a2;
        double x1 = 1;
        double x2;
        double y1 = value - a1;
        double y2;
        double delta1, delta2 = Double.MAX_VALUE;
        double fraction;
        int i = 1;
        do {
            delta1 = delta2;
            a2 = (int) (x1 / y1);
            x2 = y1;
            y2 = x1 - a2 * y1;
            numer2 = a1 * numer1 + numer0;
            denom2 = a1 * denom1 + denom0;
            fraction = (double) numer2 / (double) denom2;
            delta2 = Math.abs(value - fraction);
            a1 = a2;
            x1 = x2;
            y1 = y2;
            numer0 = numer1;
            denom0 = denom1;
            numer1 = numer2;
            denom1 = denom2;
            i++;
        } while (delta1 > delta2 && denom2 <= 10000 && denom2 > 0 && i < 25);
        if (i == 25) {
            throw new ArithmeticException("Unable to convert double to fraction");
        }
        return getReducedFraction((numer0 + wholeNumber * denom0) * sign, denom0);
    }