Function select_array

contents/barnsley/code/c/barnsley.c:32–48

This function reads in the Hutchinson operator and corresponding probabilities and returns a randomly selected transform This works by choosing a random number and then iterating through all probabilities until it finds an appropriate bin

// This works by choosing a random number and then iterating through all
// probabilities until it finds an appropriate bin
struct matrix select_array(struct matrix *hutchinson_op, double *probabilities,
                           size_t num_op)
{
    // random number to be binned
    double rnd = (double)rand() / RAND_MAX;

    // This checks to see if a random number is in a bin, if not, that
    // probability is subtracted from the random number and we check the next
    // bin in the list
    for (size_t i = 0; i < num_op; ++i) {
        if (rnd < probabilities[i]) {
            return hutchinson_op[i];
        }
        rnd -= probabilities[i];
    }
    return hutchinson_op[0];
}

// This is a general function to simulate a chaos game
//  - output_points: pointer to an initialized output array