random.hh

/// @file
/// @brief randomness

#ifndef RANDOM_HH
#define RANDOM_HH

#include <random>
#include <utility>
#include <stdexcept>
#include  <iterator>

namespace smith {
  extern std::mt19937_64 rng;
}

template<typename T> T& random_pick(std::vector<T>& container) {
  if (!container.size())
    throw std::runtime_error("No candidates available");
  
  std::uniform_int_distribution<int> pick(0, container.size()-1);
  return container[pick(smith::rng)];
}

template<typename I>
I random_pick(I beg, I end) {
    if (beg == end)
      throw std::runtime_error("No candidates available");

    std::uniform_int_distribution<> pick(0, std::distance(beg, end) - 1);
    std::advance(beg, pick(smith::rng));
    return beg;
}

template<typename I>
I random_pick(std::pair<I,I> iters) {
  return random_pick(iters.first, iters.second);
}

int d6(), d9(), d12(), d20(), d42(), d100();

#endif