ceph/src/boost/libs/histogram/examples/getting_started_listing_05.cpp

   1 // Copyright 2019 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_05
  10
  11 //////////////// Begin: put this in header file ////////////////////
  12
  13 #include <algorithm>           // std::max_element
  14 #include <boost/format.hpp>    // only needed for printing
  15 #include <boost/histogram.hpp> // make_histogram, integer, indexed
  16 #include <iostream>            // std::cout, std::endl
  17 #include <sstream>             // std::ostringstream
  18 #include <tuple>
  19 #include <vector>
  20
  21 // use this when axis configuration is fix to get highest performance
  22 struct HolderOfStaticHistogram {
  23   // put axis types here
  24   using axes_t = std::tuple<
  25     boost::histogram::axis::regular<>,
  26     boost::histogram::axis::integer<>
  27   >;
  28   using hist_t = boost::histogram::histogram<axes_t>;
  29   hist_t hist_;
  30 };
  31
  32 // use this when axis configuration should be flexible
  33 struct HolderOfDynamicHistogram {
  34   // put all axis types here that you are going to use
  35   using axis_t = boost::histogram::axis::variant<
  36     boost::histogram::axis::regular<>,
  37     boost::histogram::axis::variable<>,
  38     boost::histogram::axis::integer<>
  39   >;
  40   using axes_t = std::vector<axis_t>;
  41   using hist_t = boost::histogram::histogram<axes_t>;
  42   hist_t hist_;
  43 };
  44
  45 //////////////// End: put this in header file ////////////////////
  46
  47 int main() {
  48   using namespace boost::histogram;
  49
  50   HolderOfStaticHistogram hs;
  51   hs.hist_ = make_histogram(axis::regular<>(5, 0, 1), axis::integer<>(0, 3));
  52   // now assign a different histogram
  53   hs.hist_ = make_histogram(axis::regular<>(3, 1, 2), axis::integer<>(4, 6));
  54   // hs.hist_ = make_histogram(axis::regular<>(5, 0, 1)); does not work;
  55   // the static histogram cannot change the number or order of axis types
  56
  57   HolderOfDynamicHistogram hd;
  58   hd.hist_ = make_histogram(axis::regular<>(5, 0, 1), axis::integer<>(0, 3));
  59   // now assign a different histogram
  60   hd.hist_ = make_histogram(axis::regular<>(3, -1, 2));
  61   // and assign another
  62   hd.hist_ = make_histogram(axis::integer<>(0, 5), axis::integer<>(3, 5));
  63 }
  64
  65 //]