histogram/examples/guide_fill_histogram.cpp

44 lines
1.3 KiB
C++

//[ guide_fill_histogram
#include <boost/histogram.hpp>
#include <utility>
#include <vector>
#include <functional>
#include <numeric>
#include <cassert>
namespace bh = boost::histogram;
int main() {
auto h = bh::make_histogram(bh::axis::regular<>(8, 0, 4),
bh::axis::regular<>(10, 0, 5));
// fill histogram, number of arguments must be equal to number of axes
h(0, 1.1); // increases bin counter by one
h(bh::weight(2), 3, 3.4); // increase bin counter by 2 instead of 1
// histogram also supports fills from a container of values; a container
// of wrong size trips an assertion in debug mode
auto xy1 = std::make_pair(4, 3.1);
h(xy1);
auto xy2 = std::vector<double>({3.0, 4.9});
h(xy2);
// functional-style processing is also supported
std::vector<std::pair<int, double>> input_data{
{0, 1.2}, {2, 3.4}, {4, 5.6}};
// std::for_each takes the functor by value, we use a reference wrapper
// to avoid costly copies
auto h2 = bh::make_histogram(bh::axis::regular<>(8, 0, 4),
bh::axis::regular<>(10, 0, 5));
std::for_each(input_data.begin(), input_data.end(),
std::ref(h2));
// h2 is filled
const double sum = std::accumulate(h2.begin(), h2.end(), 0.0);
assert(sum == 3);
}
//]