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- // 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_histogram
- #include <boost/histogram.hpp>
- #include <cassert>
- int main() {
- using namespace boost::histogram;
- // Create a histogram with weight counters that keep track of a variance estimate.
- auto h = make_weighted_histogram(axis::regular<>(3, 0.0, 1.0));
- h(0.0, weight(1)); // weight 1 goes to first bin
- h(0.1, weight(2)); // weight 2 goes to first bin
- h(0.4, weight(3)); // weight 3 goes to second bin
- h(0.5, weight(4)); // weight 4 goes to second bin
- // chunk-wise filling is also supported
- auto x = {0.2, 0.6};
- auto w = {5, 6};
- h.fill(x, weight(w));
- // Weight counters have methods to access the value (sum of weights) and the variance
- // (sum of weights squared, why this gives the variance is explained in the rationale)
- assert(h[0].value() == 1 + 2 + 5);
- assert(h[0].variance() == 1 * 1 + 2 * 2 + 5 * 5);
- assert(h[1].value() == 3 + 4 + 6);
- assert(h[1].variance() == 3 * 3 + 4 * 4 + 6 * 6);
- }
- //]
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