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// 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_indexed_access
#include <boost/format.hpp>
#include <boost/histogram.hpp>
#include <cassert>
#include <iostream>
#include <numeric> // for std::accumulate
#include <sstream>
using namespace boost::histogram;
int main() {
// make histogram with 2 x 2 = 4 bins (not counting under-/overflow bins)
auto h = make_histogram(axis::regular<>(2, -1.0, 1.0), axis::regular<>(2, 2.0, 4.0));
h(weight(1), -0.5, 2.5); // bin index 0, 0
h(weight(2), -0.5, 3.5); // bin index 0, 1
h(weight(3), 0.5, 2.5); // bin index 1, 0
h(weight(4), 0.5, 3.5); // bin index 1, 1
// use the `indexed` range adaptor to iterate over all bins;
// it is not only more convenient but also faster than a hand-crafted loop!
std::ostringstream os;
for (auto&& x : indexed(h)) {
// x is a special accessor object
const auto i = x.index(0); // current index along first axis
const auto j = x.index(1); // current index along second axis
const auto b0 = x.bin(0); // current bin interval along first axis
const auto b1 = x.bin(1); // current bin interval along second axis
const auto v = *x; // "dereference" to get the bin value
os << boost::format("%i %i [%2i, %i) [%2i, %i): %i\n") % i % j % b0.lower() %
b0.upper() % b1.lower() % b1.upper() % v;
}
std::cout << os.str() << std::flush;
assert(os.str() == "0 0 [-1, 0) [ 2, 3): 1\n"
"1 0 [ 0, 1) [ 2, 3): 3\n"
"0 1 [-1, 0) [ 3, 4): 2\n"
"1 1 [ 0, 1) [ 3, 4): 4\n");
// `indexed` skips underflow and overflow bins by default, but can be called
// with the second argument `coverage::all` to walk over all bins
std::ostringstream os2;
for (auto&& x : indexed(h, coverage::all)) {
os2 << boost::format("%2i %2i: %i\n") % x.index(0) % x.index(1) % *x;
}
std::cout << os2.str() << std::flush;
assert(os2.str() == "-1 -1: 0\n"
" 0 -1: 0\n"
" 1 -1: 0\n"
" 2 -1: 0\n"
"-1 0: 0\n"
" 0 0: 1\n"
" 1 0: 3\n"
" 2 0: 0\n"
"-1 1: 0\n"
" 0 1: 2\n"
" 1 1: 4\n"
" 2 1: 0\n"
"-1 2: 0\n"
" 0 2: 0\n"
" 1 2: 0\n"
" 2 2: 0\n");
}
//]
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