Mercurial > hg > CbC > CbC_gcc
view libstdc++-v3/testsuite/20_util/hash/chi2_q_bit_flip_set.cc @ 136:4627f235cf2a
fix c-next example
author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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date | Thu, 08 Nov 2018 14:11:56 +0900 |
parents | 84e7813d76e9 |
children | 1830386684a0 |
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// Use smaller statistics when running on simulators, so it takes less time. // { dg-options "-DSAMPLES=30000" { target simulator } } // { dg-do run { target c++11 } } // Copyright (C) 2010-2018 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this library; see the file COPYING3. If not see // <http://www.gnu.org/licenses/>. #include "chi2_quality.h" // Tests chi^2 for a distribution of strings that differ from each // other by only a few bits. We start with an arbitrary base string, and // flip three random bits for each member of the set. void test_bit_flip_set() { const unsigned long N = SAMPLES; const unsigned long k = N/100; const unsigned int len = 67; const unsigned int bitlen = len * 8; const unsigned int bits_to_flip = 3; const char base[len+1] = "abcdefghijklmnopqrstuvwxyz" "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "0123456789!@#$%"; std::unordered_set<std::string> set; while (set.size() < N) { std::string s(base, base+len); for (unsigned int i = 0; i < bits_to_flip; ++i) { int bit = rand() % bitlen; s[bit/8] ^= (1 << (bit%8)); } set.insert(s); } double chi2 = chi2_hash(set, k); VERIFY( chi2 < k*1.1 ); } int main() { test_bit_flip_set(); return 0; }