random.h

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#ifndef MATH_UTIL_RANDOM_H_
#define MATH_UTIL_RANDOM_H_
 
#include <vector>
 
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/thread/mutex.hpp>
 
#ifdef BOOST_1_46
  #include <boost/nondet_random.hpp>
#else
  #include <boost/random/random_device.hpp>
#endif
 
namespace swri_math_util
{
  #ifdef BOOST_1_46
  namespace boost_random = boost;
  #else
  namespace boost_random = boost::random;
  #endif
 
  class RandomGenerator
  {
    public:
      explicit RandomGenerator(int32_t seed = -1);
      
      void GetUniformRandomSample(
        int32_t min, 
        int32_t max, 
        int32_t count,
        std::vector<int32_t>& sample);
      
    private:
      boost_random::random_device seed_;
      boost_random::mt19937 rng_;
      boost::mutex mutex_;
  };
  typedef boost::shared_ptr<RandomGenerator> RandomGeneratorPtr;
 
  template <class RNG>
  void GetUniformRandomSample(
    RNG& rng,
    int32_t min, 
    int32_t max, 
    int32_t count,
    std::vector<int32_t>& sample)
  {
    sample.clear();
    if (count < 0)
    {
      return;
    }
    
    if (min > max)
    {
      int32_t tmp = min;
      min = max;
      max = tmp;
    }
    
    int32_t range = (max - min) + 1;
    if (count > range)
    {
      count = range;
    }
 
    sample.resize(count);
      
    boost::uniform_int<> dist(min, max);
    for (int32_t i = 0; i < count; i++)
    {
      bool has_sample = false;
      while (!has_sample)
      {
        sample[i] = dist(rng);
        int32_t j;
        for (j = 0; j < i; j++)
        {
          if (sample[i] == sample[j]) break;
        }
        has_sample = j == i;
      }
    }
  }
}
 
#endif  // MATH_UTIL_RANDOM_H_