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 // clang-format off
8
9 //[ getting_started_listing_02
10
11 #include <boost/format.hpp>
12 #include <boost/histogram.hpp>
13 #include <cassert>
14 #include <iostream>
15 #include <sstream>
16 #include <string>
17
main()18 int main() {
19 using namespace boost::histogram;
20
21 /*
22 Create a histogram which can be configured dynamically at run-time. The axis
23 configuration is first collected in a vector of axis::variant type, which
24 can hold different axis types (those in its template argument list). Here,
25 we use a variant that can store a regular and a category axis.
26 */
27 using reg = axis::regular<>;
28 using cat = axis::category<std::string>;
29 using variant = axis::variant<axis::regular<>, axis::category<std::string>>;
30 std::vector<variant> axes;
31 axes.emplace_back(cat({"red", "blue"}));
32 axes.emplace_back(reg(3, 0.0, 1.0, "x"));
33 axes.emplace_back(reg(3, 0.0, 1.0, "y"));
34 // passing an iterator range also works here
35 auto h = make_histogram(std::move(axes));
36
37 // fill histogram with data, usually this happens in a loop
38 h("red", 0.1, 0.2);
39 h("blue", 0.7, 0.3);
40 h("red", 0.3, 0.7);
41 h("red", 0.7, 0.7);
42
43 /*
44 Print histogram by iterating over bins.
45 Since the [bin type] of the category axis cannot be converted into a double,
46 it cannot be handled by the polymorphic interface of axis::variant. We use
47 axis::get to "cast" the variant type to the actual category type.
48 */
49
50 // get reference to category axis, performs a run-time checked static cast
51 const auto& cat_axis = axis::get<cat>(h.axis(0));
52 std::ostringstream os;
53 for (auto&& x : indexed(h)) {
54 os << boost::format("(%i, %i, %i) %4s [%3.1f, %3.1f) [%3.1f, %3.1f) %3.0f\n")
55 % x.index(0) % x.index(1) % x.index(2)
56 % cat_axis.bin(x.index(0))
57 % x.bin(1).lower() % x.bin(1).upper()
58 % x.bin(2).lower() % x.bin(2).upper()
59 % *x;
60 }
61
62 std::cout << os.str() << std::flush;
63 assert(os.str() == "(0, 0, 0) red [0.0, 0.3) [0.0, 0.3) 1\n"
64 "(1, 0, 0) blue [0.0, 0.3) [0.0, 0.3) 0\n"
65 "(0, 1, 0) red [0.3, 0.7) [0.0, 0.3) 0\n"
66 "(1, 1, 0) blue [0.3, 0.7) [0.0, 0.3) 0\n"
67 "(0, 2, 0) red [0.7, 1.0) [0.0, 0.3) 0\n"
68 "(1, 2, 0) blue [0.7, 1.0) [0.0, 0.3) 1\n"
69 "(0, 0, 1) red [0.0, 0.3) [0.3, 0.7) 0\n"
70 "(1, 0, 1) blue [0.0, 0.3) [0.3, 0.7) 0\n"
71 "(0, 1, 1) red [0.3, 0.7) [0.3, 0.7) 0\n"
72 "(1, 1, 1) blue [0.3, 0.7) [0.3, 0.7) 0\n"
73 "(0, 2, 1) red [0.7, 1.0) [0.3, 0.7) 0\n"
74 "(1, 2, 1) blue [0.7, 1.0) [0.3, 0.7) 0\n"
75 "(0, 0, 2) red [0.0, 0.3) [0.7, 1.0) 1\n"
76 "(1, 0, 2) blue [0.0, 0.3) [0.7, 1.0) 0\n"
77 "(0, 1, 2) red [0.3, 0.7) [0.7, 1.0) 0\n"
78 "(1, 1, 2) blue [0.3, 0.7) [0.7, 1.0) 0\n"
79 "(0, 2, 2) red [0.7, 1.0) [0.7, 1.0) 1\n"
80 "(1, 2, 2) blue [0.7, 1.0) [0.7, 1.0) 0\n");
81 }
82
83 //]
84