chi2_quality.h: Break out from chi2_quality.cc.
* testsuite/20_util/hash/chi2_quality.h: Break out from chi2_quality.cc. * testsuite/20_util/hash/chi2_q_bit_flip_set.cc: Ditto. * testsuite/20_util/hash/chi2_q_document_words.cc: Ditto. * testsuite/20_util/hash/chi2_q_bit_string_set.cc: Ditto. Increase SAMPLES to 35000 for simulator targets. * testsuite/20_util/hash/chi2_q_numeric_pattern_set.cc: Ditto. * testsuite/20_util/hash/chi2_q_uniform_random.cc: Ditto. * testsuite/20_util/hash/chi2_quality.cc: Remove. From-SVN: r206167
This commit is contained in:
Hans-Peter Nilsson
Hans-Peter Nilsson
parent
96758521f7
commit
ca9431f7fe
8 changed files with 359 additions and 218 deletions
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@ -1,3 +1,15 @@
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2013-12-22 Hans-Peter Nilsson <hp@axis.com>
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* testsuite/20_util/hash/chi2_quality.h: Break out from
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chi2_quality.cc.
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* testsuite/20_util/hash/chi2_q_bit_flip_set.cc: Ditto.
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* testsuite/20_util/hash/chi2_q_document_words.cc: Ditto.
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* testsuite/20_util/hash/chi2_q_bit_string_set.cc: Ditto. Increase
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SAMPLES to 35000 for simulator targets.
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* testsuite/20_util/hash/chi2_q_numeric_pattern_set.cc: Ditto.
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* testsuite/20_util/hash/chi2_q_uniform_random.cc: Ditto.
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* testsuite/20_util/hash/chi2_quality.cc: Remove.
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2013-12-10 Paolo Carlini <paolo.carlini@oracle.com>
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* testsuite/20_util/is_base_of/value.cc: Add test.
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61
libstdc++-v3/testsuite/20_util/hash/chi2_q_bit_flip_set.cc
Normal file
61
libstdc++-v3/testsuite/20_util/hash/chi2_q_bit_flip_set.cc
Normal file
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@ -0,0 +1,61 @@
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// { dg-options "-std=gnu++0x" }
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// Use smaller statistics when running on simulators, so it takes less time.
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// { dg-options "-std=gnu++0x -DSAMPLES=30000" { target simulator } }
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// Copyright (C) 2010-2013 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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#include "chi2_quality.h"
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// Tests chi^2 for a distribution of strings that differ from each
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// other by only a few bits. We start with an arbitrary base string, and
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// flip three random bits for each member of the set.
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void
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test_bit_flip_set()
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{
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bool test __attribute__((unused)) = true;
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const unsigned long N = SAMPLES;
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const unsigned long k = N/100;
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const unsigned int len = 67;
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const unsigned int bitlen = len * 8;
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const unsigned int bits_to_flip = 3;
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const char base[len+1] = "abcdefghijklmnopqrstuvwxyz"
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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"0123456789!@#$%";
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std::unordered_set<std::string> set;
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while (set.size() < N)
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{
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std::string s(base, base+len);
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for (unsigned int i = 0; i < bits_to_flip; ++i)
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{
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int bit = rand() % bitlen;
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s[bit/8] ^= (1 << (bit%8));
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}
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set.insert(s);
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}
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double chi2 = chi2_hash(set, k);
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VERIFY( chi2 < k*1.1 );
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}
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int
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main()
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{
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test_bit_flip_set();
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return 0;
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}
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55
libstdc++-v3/testsuite/20_util/hash/chi2_q_bit_string_set.cc
Normal file
55
libstdc++-v3/testsuite/20_util/hash/chi2_q_bit_string_set.cc
Normal file
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// { dg-options "-std=gnu++0x" }
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// Use smaller statistics when running on simulators, so it takes less time.
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// For e.g. cris-elf, mipsisa32r2el-elf, powerpc-eabi and i386-linux-gnu,
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// this test fails for SAMPLES=30000.
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// { dg-options "-std=gnu++0x -DSAMPLES=35000" { target simulator } }
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// Copyright (C) 2010-2013 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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#include "chi2_quality.h"
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// Tests chi^2 for a set of strings that all consist of '1' and '0'.
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void
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test_bit_string_set()
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{
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bool test __attribute__((unused)) = true;
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const unsigned long N = SAMPLES;
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const unsigned long k = N/100;
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std::vector<std::string> set;
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std::string s;
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for (unsigned long i = 0; i < N; ++i)
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{
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s.clear();
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for (unsigned int j = 0; j < sizeof(unsigned long) * 8; ++j)
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{
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const bool bit = (1UL << j) & i;
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s.push_back(bit ? '1' : '0');
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}
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set.push_back(s);
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}
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double chi2 = chi2_hash(set, k);
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VERIFY( chi2 < k*1.1 );
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}
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int
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main()
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{
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test_bit_string_set();
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return 0;
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}
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52
libstdc++-v3/testsuite/20_util/hash/chi2_q_document_words.cc
Normal file
52
libstdc++-v3/testsuite/20_util/hash/chi2_q_document_words.cc
Normal file
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// On some simulators, the workload is simply too large with values big
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// enough for the test to pass the quality test, so just skip it altogether.
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// { dg-do run { target { ! simulator } } }
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// { dg-options "-std=gnu++0x" }
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// Copyright (C) 2010-2013 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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#include "chi2_quality.h"
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// Tests chi^2 for a set of words taken from a document written in English.
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void
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test_document_words()
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{
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bool test __attribute__((unused)) = true;
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const std::string f_name = "thirty_years_among_the_dead_preproc.txt";
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std::ifstream in(f_name);
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VERIFY( in.is_open() );
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std::vector<std::string> words;
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words.assign(std::istream_iterator<std::string>(in),
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std::istream_iterator<std::string>());
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VERIFY( words.size() > 100000 );
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std::sort(words.begin(), words.end());
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auto it = std::unique(words.begin(), words.end());
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words.erase(it, words.end());
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VERIFY( words.size() > 5000 );
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const unsigned long k = words.size() / 20;
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double chi2 = chi2_hash(words, k);
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VERIFY( chi2 < k*1.1 );
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}
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int
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main()
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{
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test_document_words();
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return 0;
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}
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// { dg-options "-std=gnu++0x" }
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// Use smaller statistics when running on simulators, so it takes less time.
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// For x86_64-linux-gnu SAMPLES=30000 fails, so increase slightly.
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// { dg-options "-std=gnu++0x -DSAMPLES=35000" { target simulator } }
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// Copyright (C) 2010-2013 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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#include "chi2_quality.h"
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// Tests chi^2 of a set of strings that all have a similar pattern,
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// intended to mimic some sort of ID string.
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void
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test_numeric_pattern_set()
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{
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bool test __attribute__((unused)) = true;
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const unsigned long N = SAMPLES;
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const unsigned long k = N/100;
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std::vector<std::string> set;
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for (unsigned long i = 0; i < N; ++i)
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{
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long i1 = i % 100000;
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long i2 = i / 100000;
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char buf[16];
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std::sprintf(buf, "XX-%05lu-%05lu", i1, i2);
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set.push_back(buf);
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}
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double chi2 = chi2_hash(set, k);
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VERIFY( chi2 < k*1.1 );
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}
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int
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main()
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{
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test_numeric_pattern_set();
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return 0;
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}
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53
libstdc++-v3/testsuite/20_util/hash/chi2_q_uniform_random.cc
Normal file
53
libstdc++-v3/testsuite/20_util/hash/chi2_q_uniform_random.cc
Normal file
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@ -0,0 +1,53 @@
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// { dg-options "-std=gnu++0x" }
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// Use smaller statistics when running on simulators, so it takes less time.
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// For powerpc-eabi, SAMPLES=30000 fails.
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// { dg-options "-std=gnu++0x -DSAMPLES=35000" { target simulator } }
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// Copyright (C) 2010-2013 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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#include "chi2_quality.h"
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// Tests chi^2 for a distribution of uniformly generated random strings.
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void
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test_uniform_random()
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{
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bool test __attribute__((unused)) = true;
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std::srand(137);
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std::unordered_set<std::string> set;
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std::string s;
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const unsigned long N = SAMPLES;
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const unsigned long k = N/100;
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const unsigned int len = 25;
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while (set.size() < N)
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{
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s.clear();
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for (unsigned int i = 0; i < len; ++i)
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s.push_back(rand() % 128);
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set.insert(s);
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}
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double chi2 = chi2_hash(set, k);
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VERIFY( chi2 < k*1.1 );
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}
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int
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main()
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{
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test_uniform_random();
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return 0;
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}
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@ -1,218 +0,0 @@
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// { dg-options "-std=gnu++0x" }
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// Use smaller statistics when running on simulators, so it takes less time.
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// { dg-options "-std=gnu++0x -DSAMPLES=30000" { target simulator } }
|
||||
|
||||
// Copyright (C) 2010-2013 Free Software Foundation, Inc.
|
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//
|
||||
// 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
|
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// <http://www.gnu.org/licenses/>.
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// This file uses the chi^2 test to measure the quality of a hash
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// function, by computing the uniformity with which it distributes a set
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// of N strings into k buckets (where k is significantly greater than N).
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//
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// Each bucket has B[i] strings in it. The expected value of each bucket
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// for a uniform distribution is z = N/k, so
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// chi^2 = Sum_i (B[i] - z)^2 / z.
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//
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// We check whether chi^2 is small enough to be consistent with the
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// hypothesis of a uniform distribution. If F(chi^2, k-1) is close to
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// 0 (where F is the cumulative probability distribution), we can
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// reject that hypothesis. So we don't want F to be too small, which
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// for large k, means we want chi^2 to be not too much larger than k.
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//
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// We use the chi^2 test for several sets of strings. Any non-horrible
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// hash function should do well with purely random strings. A really
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// good hash function will also do well with more structured sets,
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// including ones where the strings differ by only a few bits.
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#include <algorithm>
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#include <cstdlib>
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#include <cstdio>
|
||||
#include <fstream>
|
||||
#include <functional>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <string>
|
||||
#include <unordered_set>
|
||||
#include <vector>
|
||||
#include <testsuite_hooks.h>
|
||||
|
||||
#ifndef SAMPLES
|
||||
#define SAMPLES 300000
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||||
#endif
|
||||
|
||||
template <typename Container>
|
||||
double
|
||||
chi2_hash(const Container& c, long buckets)
|
||||
{
|
||||
std::vector<int> counts(buckets);
|
||||
std::hash<std::string> hasher;
|
||||
double elements = 0;
|
||||
for (auto i = c.begin(); i != c.end(); ++i)
|
||||
{
|
||||
++counts[hasher(*i) % buckets];
|
||||
++elements;
|
||||
}
|
||||
|
||||
const double z = elements / buckets;
|
||||
double sum = 0;
|
||||
for (long i = 0; i < buckets; ++i)
|
||||
{
|
||||
double delta = counts[i] - z;
|
||||
sum += delta*delta;
|
||||
}
|
||||
return sum/z;
|
||||
}
|
||||
|
||||
// Tests chi^2 for a distribution of uniformly generated random strings.
|
||||
void
|
||||
test_uniform_random()
|
||||
{
|
||||
bool test __attribute__((unused)) = true;
|
||||
std::srand(137);
|
||||
std::unordered_set<std::string> set;
|
||||
std::string s;
|
||||
const unsigned long N = SAMPLES;
|
||||
const unsigned long k = N/100;
|
||||
const unsigned int len = 25;
|
||||
while (set.size() < N)
|
||||
{
|
||||
s.clear();
|
||||
for (unsigned int i = 0; i < len; ++i)
|
||||
s.push_back(rand() % 128);
|
||||
set.insert(s);
|
||||
}
|
||||
|
||||
double chi2 = chi2_hash(set, k);
|
||||
VERIFY( chi2 < k*1.1 );
|
||||
}
|
||||
|
||||
// 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()
|
||||
{
|
||||
bool test __attribute__((unused)) = true;
|
||||
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 );
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||||
}
|
||||
|
||||
// Tests chi^2 of a set of strings that all have a similar pattern,
|
||||
// intended to mimic some sort of ID string.
|
||||
void
|
||||
test_numeric_pattern_set()
|
||||
{
|
||||
bool test __attribute__((unused)) = true;
|
||||
const unsigned long N = SAMPLES;
|
||||
const unsigned long k = N/100;
|
||||
std::vector<std::string> set;
|
||||
for (unsigned long i = 0; i < N; ++i)
|
||||
{
|
||||
long i1 = i % 100000;
|
||||
long i2 = i / 100000;
|
||||
char buf[16];
|
||||
std::sprintf(buf, "XX-%05lu-%05lu", i1, i2);
|
||||
set.push_back(buf);
|
||||
}
|
||||
|
||||
double chi2 = chi2_hash(set, k);
|
||||
VERIFY( chi2 < k*1.1 );
|
||||
}
|
||||
|
||||
// Tests chi^2 for a set of strings that all consist of '1' and '0'.
|
||||
void
|
||||
test_bit_string_set()
|
||||
{
|
||||
bool test __attribute__((unused)) = true;
|
||||
const unsigned long N = SAMPLES;
|
||||
const unsigned long k = N/100;
|
||||
std::vector<std::string> set;
|
||||
std::string s;
|
||||
for (unsigned long i = 0; i < N; ++i)
|
||||
{
|
||||
s.clear();
|
||||
for (unsigned int j = 0; j < sizeof(unsigned long) * 8; ++j)
|
||||
{
|
||||
const bool bit = (1UL << j) & i;
|
||||
s.push_back(bit ? '1' : '0');
|
||||
}
|
||||
set.push_back(s);
|
||||
}
|
||||
|
||||
double chi2 = chi2_hash(set, k);
|
||||
VERIFY( chi2 < k*1.1 );
|
||||
}
|
||||
|
||||
// Tests chi^2 for a set of words taken from a document written in English.
|
||||
void
|
||||
test_document_words()
|
||||
{
|
||||
// That file is 187587 single-word lines. To avoid a timeout, just skip
|
||||
// this part, which would take up to 95% of the program runtime (with
|
||||
// SAMPLES == 10000), if we're not supposed to run anywhere that long.
|
||||
#if SAMPLES >= 100000
|
||||
bool test __attribute__((unused)) = true;
|
||||
const std::string f_name = "thirty_years_among_the_dead_preproc.txt";
|
||||
std::ifstream in(f_name);
|
||||
VERIFY( in.is_open() );
|
||||
std::vector<std::string> words;
|
||||
words.assign(std::istream_iterator<std::string>(in),
|
||||
std::istream_iterator<std::string>());
|
||||
VERIFY( words.size() > 100000 );
|
||||
std::sort(words.begin(), words.end());
|
||||
auto it = std::unique(words.begin(), words.end());
|
||||
words.erase(it, words.end());
|
||||
VERIFY( words.size() > 5000 );
|
||||
|
||||
const unsigned long k = words.size() / 20;
|
||||
double chi2 = chi2_hash(words, k);
|
||||
VERIFY( chi2 < k*1.1 );
|
||||
#endif
|
||||
}
|
||||
|
||||
int
|
||||
main()
|
||||
{
|
||||
test_uniform_random();
|
||||
test_bit_flip_set();
|
||||
test_numeric_pattern_set();
|
||||
test_bit_string_set();
|
||||
test_document_words();
|
||||
return 0;
|
||||
}
|
||||
74
libstdc++-v3/testsuite/20_util/hash/chi2_quality.h
Normal file
74
libstdc++-v3/testsuite/20_util/hash/chi2_quality.h
Normal file
|
|
@ -0,0 +1,74 @@
|
|||
// Copyright (C) 2010-2013 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/>.
|
||||
|
||||
// This file uses the chi^2 test to measure the quality of a hash
|
||||
// function, by computing the uniformity with which it distributes a set
|
||||
// of N strings into k buckets (where k is significantly greater than N).
|
||||
//
|
||||
// Each bucket has B[i] strings in it. The expected value of each bucket
|
||||
// for a uniform distribution is z = N/k, so
|
||||
// chi^2 = Sum_i (B[i] - z)^2 / z.
|
||||
//
|
||||
// We check whether chi^2 is small enough to be consistent with the
|
||||
// hypothesis of a uniform distribution. If F(chi^2, k-1) is close to
|
||||
// 0 (where F is the cumulative probability distribution), we can
|
||||
// reject that hypothesis. So we don't want F to be too small, which
|
||||
// for large k, means we want chi^2 to be not too much larger than k.
|
||||
//
|
||||
// We use the chi^2 test for several sets of strings. Any non-horrible
|
||||
// hash function should do well with purely random strings. A really
|
||||
// good hash function will also do well with more structured sets,
|
||||
// including ones where the strings differ by only a few bits.
|
||||
|
||||
#include <algorithm>
|
||||
#include <cstdlib>
|
||||
#include <cstdio>
|
||||
#include <fstream>
|
||||
#include <functional>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <string>
|
||||
#include <unordered_set>
|
||||
#include <vector>
|
||||
#include <testsuite_hooks.h>
|
||||
|
||||
#ifndef SAMPLES
|
||||
#define SAMPLES 300000
|
||||
#endif
|
||||
|
||||
template <typename Container>
|
||||
double
|
||||
chi2_hash(const Container& c, long buckets)
|
||||
{
|
||||
std::vector<int> counts(buckets);
|
||||
std::hash<std::string> hasher;
|
||||
double elements = 0;
|
||||
for (auto i = c.begin(); i != c.end(); ++i)
|
||||
{
|
||||
++counts[hasher(*i) % buckets];
|
||||
++elements;
|
||||
}
|
||||
|
||||
const double z = elements / buckets;
|
||||
double sum = 0;
|
||||
for (long i = 0; i < buckets; ++i)
|
||||
{
|
||||
double delta = counts[i] - z;
|
||||
sum += delta*delta;
|
||||
}
|
||||
return sum/z;
|
||||
}
|
||||
Loading…
Add table
Reference in a new issue