histogram/examples/guide_fill_weighted_profile.cpp
Hans Dembinski 14f36ea932
new and updated examples for user guide (#210)
* new accmulator examples for user guide
* new weighted profile example
* minor corrections to other examples
2019-09-10 23:19:27 +02:00

52 lines
2.0 KiB
C++

// Copyright 2019 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_fill_weighted_profile
#include <boost/format.hpp>
#include <boost/histogram.hpp>
#include <cassert>
#include <iostream>
#include <sstream>
int main() {
using namespace boost::histogram;
using namespace boost::histogram::literals; // _c suffix creates compile-time numbers
// make 2D weighted profile
auto h = make_weighted_profile(axis::integer<>(0, 2), axis::integer<>(0, 2));
// The mean is computed from the values marked with the sample() helper function.
// Weights can be passed as well. The `sample` and `weight` arguments can appear in any
// order, but they must be the first or last arguments.
h(0, 0, sample(1)); // sample goes to cell (0, 0); weight is 1
h(0, 0, sample(2), weight(3)); // sample goes to cell (0, 0); weight is 3
h(1, 0, sample(3)); // sample goes to cell (1, 0); weight is 1
h(1, 0, sample(4)); // sample goes to cell (1, 0); weight is 1
h(0, 1, sample(5)); // sample goes to cell (1, 0); weight is 1
h(0, 1, sample(6)); // sample goes to cell (1, 0); weight is 1
h(1, 1, weight(4), sample(7)); // sample goes to cell (1, 1); weight is 4
h(weight(5), sample(8), 1, 1); // sample goes to cell (1, 1); weight is 5
std::ostringstream os;
for (auto&& x : indexed(h)) {
const auto i = x.index(0_c);
const auto j = x.index(1_c);
const auto m = x->value(); // weighted mean
const auto v = x->variance(); // estimated variance of weighted mean
os << boost::format("index %i,%i mean %.1f variance %.1f\n") % i % j % m % v;
}
std::cout << os.str() << std::flush;
assert(os.str() == "index 0,0 mean 1.8 variance 0.5\n"
"index 1,0 mean 3.5 variance 0.5\n"
"index 0,1 mean 5.5 variance 0.5\n"
"index 1,1 mean 7.6 variance 0.5\n");
}
//]