// Copyright 2015-2016 Hans Dembinski
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)

#include <boost/histogram/histogram.hpp>
#include <boost/histogram/axis.hpp>
#include <boost/random.hpp>
#include <boost/array.hpp>

#include <algorithm>
#include <limits>
#include <vector>
#include <ctime>
#include <cstdio>

using namespace std;
using namespace boost::histogram;

template <typename D>
struct rng {
  boost::random::mt19937 r;
  D d;
  rng(double a, double b) : d(a, b) {}
  double operator()() { return d(r); }
};

vector<double> random_array(unsigned n, int type) {
  using namespace boost::random;
  std::vector<double> result;
  switch (type) {
    case 0:
      std::generate_n(std::back_inserter(result), n, rng<uniform_real_distribution<> >(0.0, 1.0));
      break;
    case 1:
      std::generate_n(std::back_inserter(result), n, rng<normal_distribution<> >(0.0, 0.3));
      break;
  }
  return result;
}

void compare_1d(unsigned n, int distrib)
{
  vector<double> r = random_array(n, distrib);

  double best_boost = std::numeric_limits<double>::max();
  for (unsigned k = 0; k < 10; ++k) {
    histogram h(regular_axis(100, 0, 1));
    t = clock();
    for (unsigned i = 0; i < n; ++i)
      h.fill(r[i]);
    t = clock() - t;
    best_boost = std::min(best_boost, double(t) / CLOCKS_PER_SEC);
    // printf("root %g this %g\n", hroot.GetSum(), h.sum());
    assert(hroot.GetSum() == h.sum());
  }

  printf("1D\n");
  printf("t[boost] = %.3f\n", best_boost);
}

void compare_3d(unsigned n, int distrib)
{
  vector<double> r = random_array(3 * n, distrib);

  double best_boost = std::numeric_limits<double>::max();
  for (unsigned k = 0; k < 10; ++k) {
    histogram h(regular_axis(100, 0, 1),
                 regular_axis(100, 0, 1),
                 regular_axis(100, 0, 1));
    t = clock();
    for (unsigned i = 0; i < n; ++i)
      h.fill(r[3 * i], r[3 * i + 1], r[3 * i + 2]);
    t = clock() - t;
    best_boost = std::min(best_boost, double(t) / CLOCKS_PER_SEC);
    assert(hroot.GetSum() == h.sum());
  } 

  printf("3D\n");
  printf("t[boost] = %.3f\n", best_boost);
}

void compare_6d(unsigned n, int distrib)
{
  vector<double> r = random_array(6 * n, distrib);

  double best_boost = std::numeric_limits<double>::max();
  for (unsigned k = 0; k < 10; ++k) {
    double x[6];

    histogram h(regular_axis(10, 0, 1),
                regular_axis(10, 0, 1),
                regular_axis(10, 0, 1),
                regular_axis(10, 0, 1),
                regular_axis(10, 0, 1),
                regular_axis(10, 0, 1));

    t = clock();
    for (unsigned i = 0; i < n; ++i) {
      for (unsigned k = 0; k < 6; ++k)
        x[k] = r[6 * i + k];      
      h.fill(x, x+6);
    }
    t = clock() - t;
    best_boost = std::min(best_boost, double(t) / CLOCKS_PER_SEC);
  } 

  printf("6D\n");
  printf("t[boost] = %.3f\n", best_boost);
}

int main() {
  printf("uniform distribution\n");
  compare_1d(12000000, 0);
  compare_3d(4000000, 0);
  compare_6d(2000000, 0);
  printf("normal distribution\n");
  compare_1d(12000000, 1);
  compare_3d(4000000, 1);
  compare_6d(2000000, 1);
}