ceph/src/boost/libs/random/test/test_discrete.cpp

   1 /* test_poisson.cpp
   2  *
   3  * Copyright Steven Watanabe 2010
   4  * Distributed under the Boost Software License, Version 1.0. (See
   5  * accompanying file LICENSE_1_0.txt or copy at
   6  * http://www.boost.org/LICENSE_1_0.txt)
   7  *
   8  * $Id$
   9  *
  10  */
  11
  12 #include <boost/random/discrete_distribution.hpp>
  13 #include <boost/random/uniform_int.hpp>
  14 #include <boost/random/mersenne_twister.hpp>
  15 #include <boost/lexical_cast.hpp>
  16 #include <boost/exception/diagnostic_information.hpp>
  17 #include <vector>
  18 #include <iostream>
  19 #include <numeric>
  20
  21 #include "chi_squared_test.hpp"
  22
  23 bool do_test(int n, long long max) {
  24     std::cout << "running discrete(p0, p1, ..., p" << n-1 << ")" << " " << max << " times: " << std::flush;
  25
  26     std::vector<double> expected;
  27     {
  28         boost::mt19937 egen;
  29         for(int i = 0; i < n; ++i) {
  30             expected.push_back(egen());
  31         }
  32         double sum = std::accumulate(expected.begin(), expected.end(), 0.0);
  33         for(std::vector<double>::iterator iter = expected.begin(), end = expected.end(); iter != end; ++iter) {
  34             *iter /= sum;
  35         }
  36     }
  37
  38     boost::random::discrete_distribution<> dist(expected);
  39     boost::mt19937 gen;
  40     std::vector<long long> results(expected.size());
  41     for(long long i = 0; i < max; ++i) {
  42         ++results[dist(gen)];
  43     }
  44
  45     long long sum = std::accumulate(results.begin(), results.end(), 0ll);
  46     if(sum != max) {
  47         std::cout << "*** Failed: incorrect total: " << sum << " ***" << std::endl;
  48         return false;
  49     }
  50     double chsqr = chi_squared_test(results, expected, max);
  51
  52     bool result = chsqr < 0.99;
  53     const char* err = result? "" : "*";
  54     std::cout << std::setprecision(17) << chsqr << err << std::endl;
  55
  56     std::cout << std::setprecision(6);
  57
  58     return result;
  59 }
  60
  61 bool do_tests(int repeat, int max_n, long long trials) {
  62     boost::mt19937 gen;
  63     boost::uniform_int<> idist(1, max_n);
  64     int errors = 0;
  65     for(int i = 0; i < repeat; ++i) {
  66         if(!do_test(idist(gen), trials)) {
  67             ++errors;
  68         }
  69     }
  70     if(errors != 0) {
  71         std::cout << "*** " << errors << " errors detected ***" << std::endl;
  72     }
  73     return errors == 0;
  74 }
  75
  76 int usage() {
  77     std::cerr << "Usage: test_discrete -r <repeat> -n <max n> -t <trials>" << std::endl;
  78     return 2;
  79 }
  80
  81 template<class T>
  82 bool handle_option(int& argc, char**& argv, char opt, T& value) {
  83     if(argv[0][1] == opt && argc > 1) {
  84         --argc;
  85         ++argv;
  86         value = boost::lexical_cast<T>(argv[0]);
  87         return true;
  88     } else {
  89         return false;
  90     }
  91 }
  92
  93 int main(int argc, char** argv) {
  94     int repeat = 10;
  95     int max_n = 10000;
  96     long long trials = 1000000ll;
  97
  98     if(argc > 0) {
  99         --argc;
 100         ++argv;
 101     }
 102     while(argc > 0) {
 103         if(argv[0][0] != '-') return usage();
 104         else if(!handle_option(argc, argv, 'r', repeat)
 105              && !handle_option(argc, argv, 'n', max_n)
 106              && !handle_option(argc, argv, 't', trials)) {
 107             return usage();
 108         }
 109         --argc;
 110         ++argv;
 111     }
 112
 113     try {
 114         if(do_tests(repeat, max_n, trials)) {
 115             return 0;
 116         } else {
 117             return EXIT_FAILURE;
 118         }
 119     } catch(...) {
 120         std::cerr << boost::current_exception_diagnostic_information() << std::endl;
 121         return EXIT_FAILURE;
 122     }
 123 }