My first thought is that you probably shouldn't reinitialize the generator for every random number you need. I would recommend that you create and seed "generator" once at the start of your program, then reuse it whenever you need a random number. Perhaps something like the following: namespace Random { typedef boost::minstd_rand base_generator_type; typedef boost::uniform_int<> distribution_type; typedef boost::variate_generator<base_generator_type&, distribution_type> gen_type; //Declare the generator as a global variable for easy reuse base_generator_type generator(static_cast<unsigned long>(clock())); /*************************************************** * initializes the random number generator * **************************************************/ void initialize() { for (int i = 0; i < 30000; ++i) generator.seed(static_cast<unsigned long>(clock())); } /*************************************************** * generates a random number between a and b * * @param a the starting range * * @param b the integer ending range * * @return N such that a <= N <= b * **************************************************/ template <class T> T rand_int (const T& a, const T& b) { //Check the parameters BOOST_STATIC_ASSERT(boost::is_integral<T>::value); assert (b >= a); //Set up the desired distribution gen_type ran_gen(generator, distribution_type(a, b)); //Get a random number return ran_gen(); } } using Random::rand_int; int main(int argc, char* argv[]) { Random::initialize(); std::cout << rand_int (1,1000) << std::endl << rand_int (1,1000) << std::endl << rand_int (1,1000) << std::endl << rand_int (1,1000) << std::endl; return 0; } ________________________________________ From: chun ping wang [mailto:cablepuff@gmail.com] Sent: Friday, May 19, 2006 3:55 AM To: boost-users@lists.boost.org Subject: [Boost-users] Newbie question: Random numbers. I have a simple question, is there a very fast and effecient way to generate random numbers that are fast on the fly. The numbers are really randomize and distorted... /*************************************************** * generates a random number between a and b * * @param a the starting range * * @param b the integer ending range * * @return N such that a <= N <= b * **************************************************/ template <class T> T randint(const T& a, const T& b) { BOOST_STATIC_ASSERT(boost::is_integral<T>::value); assert (b >= a); typedef boost::minstd_rand base_generator_type; typedef boost::uniform_int<> distribution_type; typedef boost::variate_generator<base_generator_type&, distribution_type> gen_type; base_generator_type generator(boost::numeric_cast<unsigned long>(clock())); gen_type ran_gen(generator, distribution_type(a, b)); for (int i = 0; i < 30000; ++i) generator.seed(boost::numeric_cast<unsigned long>(clock())); return ran_gen(); } This works but is super slow... are there effective ways to do it... Thanks.