// Copyright 2015-2018 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)

//[ guide_access_bin_counts

#include <boost/histogram.hpp>
#include <cassert>
#include <numeric> // for std::accumulate

namespace bh = boost::histogram;

int main() {
  // make histogram with 2 x 2 = 4 bins (not counting under-/overflow bins)
  auto h =
      bh::make_histogram(bh::axis::regular<>(2, -1, 1), bh::axis::regular<>(2, 2, 4));

  h(bh::weight(1), -0.5, 2.5); // bin index 0, 0
  h(bh::weight(2), -0.5, 3.5); // bin index 0, 1
  h(bh::weight(3), 0.5, 2.5);  // bin index 1, 0
  h(bh::weight(4), 0.5, 3.5);  // bin index 1, 1

  // access count value, number of indices must match number of axes
  assert(h.at(0, 0) == 1);
  assert(h.at(0, 1) == 2);
  assert(h.at(1, 0) == 3);
  assert(h.at(1, 1) == 4);

  // access via from tuple are also supported; passing a tuple of wrong size
  // causes an error at compile-time or an assertion at runtime in debug mode
  auto idx = std::make_tuple(0, 1);
  assert(h.at(idx) == 2);

  // histogram has bin iterators which iterate over all bin values including
  // underflow/overflow; it works with STL algorithms
  auto sum = std::accumulate(h.begin(), h.end(), 0.0);
  assert(sum == 10);

  // often you need the multi-dimensional bin index in addition to the bin value, which
  // indexded(...) provides; it creates a range object, which provides a pair of the index
  // and the value (note: iteration order is an implementation detail, don't rely on it)
  std::ostringstream os;
  for (auto x : indexed(h)) {
    os << std::setw(2) << x[0] << " " << std::setw(2) << x[1] << ": " << x.value << "\n";
  }

  std::cout << os.str() << std::flush;

  assert(os.str() == " 0  0: 1\n"
                     " 1  0: 3\n"
                     " 2  0: 0\n"
                     "-1  0: 0\n"
                     " 0  1: 2\n"
                     " 1  1: 4\n"
                     " 2  1: 0\n"
                     "-1  1: 0\n"
                     " 0  2: 0\n"
                     " 1  2: 0\n"
                     " 2  2: 0\n"
                     "-1  2: 0\n"
                     " 0 -1: 0\n"
                     " 1 -1: 0\n"
                     " 2 -1: 0\n"
                     "-1 -1: 0\n");
}

//]