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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_profile
- #include <boost/format.hpp>
- #include <boost/histogram.hpp>
- #include <cassert>
- #include <iostream>
- #include <sstream>
- #include <tuple>
- int main() {
- using namespace boost::histogram;
- // make a profile, it computes the mean of the samples in each histogram cell
- auto h = make_profile(axis::integer<>(0, 3));
- // mean is computed from the values marked with the sample() helper function
- h(0, sample(1)); // sample goes to cell 0
- h(0, sample(2)); // sample goes to cell 0
- h(1, sample(3)); // sample goes to cell 1
- h(sample(4), 1); // sample goes to cell 1; sample can be first or last argument
- // fills from tuples are also supported, 5 and 6 go to cell 2
- auto a = std::make_tuple(2, sample(5));
- auto b = std::make_tuple(sample(6), 2);
- h(a);
- h(b);
- // builtin accumulators have methods to access their state
- std::ostringstream os;
- for (auto&& x : indexed(h)) {
- // use `.` to access methods of accessor, like `index()`
- // use `->` to access methods of accumulator
- const auto i = x.index();
- const auto n = x->count(); // how many samples are in this bin
- const auto vl = x->value(); // mean value
- const auto vr = x->variance(); // estimated variance of the mean value
- os << boost::format("index %i count %i value %.1f variance %.1f\n") % i % n % vl % vr;
- }
- std::cout << os.str() << std::flush;
- assert(os.str() == "index 0 count 2 value 1.5 variance 0.5\n"
- "index 1 count 2 value 3.5 variance 0.5\n"
- "index 2 count 2 value 5.5 variance 0.5\n");
- }
- //]
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