1 // Copyright 2015-2018 Hans Dembinski
2 //
3 // Distributed under the Boost Software License, Version 1.0.
4 // (See accompanying file LICENSE_1_0.txt
5 // or copy at http://www.boost.org/LICENSE_1_0.txt)
6
7 //[ guide_custom_minimal_axis
8
9 #include <boost/histogram.hpp>
10 #include <cassert>
11
main()12 int main() {
13 using namespace boost::histogram;
14
15 // stateless axis which returns 1 if the input is even and 0 otherwise
16 struct even_odd_axis {
17 axis::index_type index(int x) const { return x % 2; }
18 axis::index_type size() const { return 2; }
19 };
20
21 // threshold axis which returns 1 if the input is above threshold
22 struct threshold_axis {
23 threshold_axis(double x) : thr(x) {}
24 axis::index_type index(double x) const { return x >= thr; }
25 axis::index_type size() const { return 2; }
26 double thr;
27 };
28
29 auto h = make_histogram(even_odd_axis(), threshold_axis(3.0));
30
31 h(0, 2.0);
32 h(1, 4.0);
33 h(2, 4.0);
34
35 assert(h.at(0, 0) == 1); // even, below threshold
36 assert(h.at(0, 1) == 1); // even, above threshold
37 assert(h.at(1, 0) == 0); // odd, below threshold
38 assert(h.at(1, 1) == 1); // odd, above threshold
39 }
40
41 //]
42