libstdc++-v3/testsuite/20_util/hash/chi2_q_bit_string_set.cc

   1 // Use smaller statistics when running on simulators, so it takes less time.
   2 // For e.g. cris-elf, mipsisa32r2el-elf, powerpc-eabi and i386-linux-gnu,
   3 // this test fails for SAMPLES=30000.
   4 // { dg-options "-DSAMPLES=35000" { target simulator } }
   5 // { dg-do run { target c++11 } }
   6
   7 // Copyright (C) 2010-2024 Free Software Foundation, Inc.
   8 //
   9 // This file is part of the GNU ISO C++ Library.  This library is free
  10 // software; you can redistribute it and/or modify it under the
  11 // terms of the GNU General Public License as published by the
  12 // Free Software Foundation; either version 3, or (at your option)
  13 // any later version.
  14 //
  15 // This library is distributed in the hope that it will be useful,
  16 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 // GNU General Public License for more details.
  19 //
  20 // You should have received a copy of the GNU General Public License
  21 // along with this library; see the file COPYING3.  If not see
  22 // <http://www.gnu.org/licenses/>.
  23
  24 #include "chi2_quality.h"
  25
  26 // Tests chi^2 for a set of strings that all consist of '1' and '0'.
  27 void
  28 test_bit_string_set()
  29 {
  30   const unsigned long N = SAMPLES;
  31   const unsigned long k = N/100;
  32   std::vector<std::string> set;
  33   std::string s;
  34   for (unsigned long i = 0; i < N; ++i)
  35     {
  36       s.clear();
  37       for (unsigned int j = 0; j < sizeof(unsigned long) * 8; ++j)
  38         {
  39           const bool bit = (1UL << j) & i;
  40           s.push_back(bit ? '1' : '0');
  41         }
  42       set.push_back(s);
  43     }
  44
  45   double chi2 = chi2_hash(set, k);
  46   VERIFY( chi2 < k*1.1 );
  47 }
  48
  49 int
  50 main()
  51 {
  52   test_bit_string_set();
  53   return 0;
  54 }