public double sample()

in commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/AhrensDieterExponentialSampler.java [99:137]

• 23 lines of code
• 5 McCabe index (conditional complexity)

    public double sample() {
        // Step 1:
        double a = 0;
        // Avoid u=0 which creates an infinite loop
        double u = InternalUtils.makeNonZeroDouble(rng.nextLong());

        // Step 2 and 3:
        while (u < 0.5) {
            a += EXPONENTIAL_SA_QI[0];
            u *= 2;
        }

        // Step 4 (now u >= 0.5):
        u += u - 1;

        // Step 5:
        if (u <= EXPONENTIAL_SA_QI[0]) {
            return mean * (a + u);
        }

        // Step 6:
        int i = 0; // Should be 1, be we iterate before it in while using 0.
        double u2 = rng.nextDouble();
        double umin = u2;

        // Step 7 and 8:
        do {
            ++i;
            u2 = rng.nextDouble();

            if (u2 < umin) {
                umin = u2;
            }

            // Step 8:
        } while (u > EXPONENTIAL_SA_QI[i]); // Ensured to exit since EXPONENTIAL_SA_QI[MAX] = 1.

        return mean * (a + umin * EXPONENTIAL_SA_QI[0]);
    }