14f36ea932
* new accmulator examples for user guide * new weighted profile example * minor corrections to other examples
45 lines
1.3 KiB
C++
45 lines
1.3 KiB
C++
// Copyright 2018 Hans Dembinski
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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//[ guide_custom_accumulators_2
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#include <boost/format.hpp>
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#include <boost/histogram.hpp>
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#include <cassert>
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#include <iostream>
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#include <sstream>
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int main() {
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using namespace boost::histogram;
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// Make a custom accumulator, which tracks the maximum of the samples.
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// It must have a call operator that accepts the argument of the `sample` function.
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struct maximum {
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// return value is ignored, so we use void
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void operator()(double x) {
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if (x > value) value = x;
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}
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double value = 0; // value is initialized to zero
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};
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// Create 1D histogram that uses the custom accumulator.
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auto h = make_histogram_with(dense_storage<maximum>(), axis::integer<>(0, 2));
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h(0, sample(1.0)); // sample goes to first cell
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h(0, sample(2.0)); // sample goes to first cell
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h(1, sample(3.0)); // sample goes to second cell
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h(1, sample(4.0)); // sample goes to second cell
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std::ostringstream os;
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for (auto&& x : indexed(h)) {
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os << boost::format("index %i maximum %.1f\n") % x.index() % x->value;
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}
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std::cout << os.str() << std::flush;
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assert(os.str() == "index 0 maximum 2.0\n"
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"index 1 maximum 4.0\n");
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}
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//]
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