Class Random

include/LightGBM/utils/random.h:18–112

! * \brief A wrapper for random generator */

* \brief A wrapper for random generator
*/
class Random {
 public:
  /*!
  * \brief Constructor, with random seed
  */
  Random() {
    std::random_device rd;
    auto genrator = std::mt19937(rd());
    std::uniform_int_distribution<int> distribution(0, x);
    x = distribution(genrator);
  }
  /*!
  * \brief Constructor, with specific seed
  */
  explicit Random(int seed) {
    x = seed;
  }
  /*!
  * \brief Generate random integer, int16 range. [0, 65536]
  * \param lower_bound lower bound
  * \param upper_bound upper bound
  * \return The random integer between [lower_bound, upper_bound)
  */
  inline int NextShort(int lower_bound, int upper_bound) {
    return (RandInt16()) % (upper_bound - lower_bound) + lower_bound;
  }

  /*!
  * \brief Generate random integer, int32 range
  * \param lower_bound lower bound
  * \param upper_bound upper bound
  * \return The random integer between [lower_bound, upper_bound)
  */
  inline int NextInt(int lower_bound, int upper_bound) {
    return (RandInt32()) % (upper_bound - lower_bound) + lower_bound;
  }

  /*!
  * \brief Generate random float data
  * \return The random float between [0.0, 1.0)
  */
  inline float NextFloat() {
    // get random float in [0,1)
    return static_cast<float>(RandInt16()) / (32768.0f);
  }
  /*!
  * \brief Sample K data from {0,1,...,N-1}
  * \param N
  * \param K
  * \return K Ordered sampled data from {0,1,...,N-1}
  */
  inline std::vector<int> Sample(int N, int K) {
    std::vector<int> ret;
    ret.reserve(K);
    if (K > N || K <= 0) {
      return ret;
    } else if (K == N) {
      for (int i = 0; i < N; ++i) {