random.cpp

dysii是一款非常出色的滤波函数库

//#if defined(__GNUC__) && defined(GCC_PCH)
//  #include "aux.hpp"
//#else
  #include "Random.hpp"
//#endif

#include "boost/mpi.hpp"

#include <time.h>
#include <assert.h>

using namespace indii::ml::aux;

bool Random::isInit = false;

gsl_rng* Random::rng = NULL;

double Random::uniform(const double lower, const double upper) {
  if (!isInit) {
    init();
  }
  return lower + gsl_rng_uniform(rng) * (upper - lower);
}

double Random::gaussian(const double mean, const double sigma) {
  if (!isInit) {
    init();
  }
  if (sigma == 0.0) {
    return mean;
  } else {
    return mean + gsl_ran_gaussian(rng, sigma);
  }
}

void Random::seed(unsigned int seed) {
  if (!isInit) {
    init();
  }
  gsl_rng_set(rng, seed);
}

void Random::init() {
  int seed;

  /* construct random number generator */
  gsl_rng_env_setup();
  //rng = gsl_rng_alloc(gsl_rng_ranlxd2); // best randomness
  rng = gsl_rng_alloc(gsl_rng_mt19937); // best randomness/speed tradeoff

  /* select seed */
  seed = time(NULL);
  if (boost::mpi::environment::initialized()) {
    /* ensure two nodes aren't seeded with the same number */
    boost::mpi::communicator world;
    const int rank = world.rank();
    seed += 1000 * rank;
  }

  /* seed random number generator */
  gsl_rng_set(rng, seed);
  isInit = true;

  /* post-condition */
  assert (isInit);
}

void Random::terminate() {
  if (isInit) {
    gsl_rng_free(rng);
  }
}