BitMagic-C++: sample11.cpp Source File

BitMagic-C++

sample11.cpp
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1 /*
2 Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15
16 For more information please visit: http://bitmagic.io
17 */
18
19 /** \example sample11.cpp
20 Example of how to use various bit counting techniques
21
22 \sa bm::bvector<>::count()
23 \sa bm::bvector<>::count_range()
24 \sa bm::bvector<>::count_to()
25 \sa bm::count_and()
26 \sa bm::bvector<>::counted_enumerator
27 */
28
29 /*! \file sample11.cpp
30 \brief Example: bvector<> bit-counting techniques analysis
31 */
32
33 #include <iostream>
34 #include <random>
35 #include <memory>
36
37 #include "bm.h"
38 #include "bmalgo.h"
39 #include "bmtimer.h"
40
41 using namespace std;
42
43 // timing storage for benchmarking
44 bm::chrono_taker::duration_map_type timing_map;
45
46 const unsigned benchmark_count = 10000;
47 unsigned vector_max = 400000000;
48
49 std::random_device rand_dev;
50 std::mt19937 gen(rand_dev()); // mersenne_twister_engine
51 std::uniform_int_distribution<> rand_dis(1, int(vector_max)); // generate uniform numebrs for [1, vector_max]
52
53
54 /// generate pseudo-random bit-vector, mix of blocks
55 ///
56 static
57 void generate_bvector(bm::bvector<>& bv)
58 {
59 bm::bvector<>::size_type i, j;
60 for (i = 0; i < vector_max;)
61 {
62 // generate bit-blocks
63 for (j = 0; j < 65535*8; i += 10, j++)
64 {
65 bv.set(i);
66 }
67 if (i > vector_max)
68 break;
69 // generate GAP (compressed) blocks
70 for (j = 0; j < 65535; i += 120, j++)
71 {
72 unsigned len = rand() % 64;
73 bv.set_range(i, i + len);
74 i += len;
75 if (i > vector_max)
76 break;
77 }
78 }
79
80 // compress vector
81 BM_DECLARE_TEMP_BLOCK(tb)
82 bv.optimize(tb);
83
84 // compute bit-vector statistics
85 bm::bvector<>::statistics st;
86 bv.calc_stat(&st);
87
88 std::cout << "Bit-vector statistics: GAP (compressed blocks)=" << st.gap_blocks
89 << ", BIT (uncompressed blocks)=" << st.bit_blocks
90 << std::endl << std::endl;
91 }
92
93 /// "pre-heat" CPU to minimize dynamic overclocking effects
94 ///
95 static
96 bm::bvector<>::size_type pre_heat(const bm::bvector<>& bv)
97 {
98 bm::bvector<>::size_type cnt = 0;
99 bm::bvector<>::size_type m = 1;
100 for (unsigned i = 0; i < benchmark_count; ++i)
101 {
102 cnt += bv.count();
103 m+=cnt*cnt;
104 }
105 return m;
106 }
107
108
109
110 /// simple population count for the whole vector
111 ///
112 static
113 void bv_count_test(const bm::bvector<>& bv)
114 {
115 bm::bvector<>::size_type cnt = 0;
116
117 {
118 bm::chrono_taker tt1("1. bvector<>::count()", benchmark_count / 2, &timing_map);
119 for (unsigned i = 0; i < benchmark_count / 2; ++i)
120 {
121 cnt += bv.count();
122 }
123 }
124 // this is mostly to prevent compiler to optimize loop away
125 std::cout << "Count test finished." << cnt << "\r";
126 }
127
128 /// count_range() test
129 ///
130 static
131 void bv_count_range(const bm::bvector<>& bv)
132 {
133 bm::bvector<>::size_type cnt = 0;
134 {
135 bm::chrono_taker tt1("2. bvector<>::count_range()", benchmark_count, &timing_map);
136 for (unsigned i = 0; i < benchmark_count; ++i)
137 {
138 unsigned from = unsigned(rand_dis(gen));
139 unsigned to = unsigned(rand_dis(gen));
140 if (from > to)
141 swap(from, to);
142 cnt += bv.count_range(from, to);
143 }
144 }
145 // this is mostly to prevent compiler to optimize loop away
146 std::cout << "Count range test finished." << cnt << "\r";
147 }
148
149 /// count_range() test using pre-calculated blocks bit count
150 ///
151 static
152 void bv_count_range_acc(const bm::bvector<>& bv)
153 {
154 bm::bvector<>::size_type cnt = 0;
155
156 std::unique_ptr<bm::bvector<>::rs_index_type> rs(new bm::bvector<>::rs_index_type());
157 bv.build_rs_index(rs.get());
158
159 {
160 bm::chrono_taker tt1("3. bvector<>::count_range() with rs_index", benchmark_count, &timing_map);
161 cnt = 0;
162 for (unsigned i = 0; i < benchmark_count; ++i)
163 {
164 unsigned from = unsigned(rand_dis(gen));
165 unsigned to = unsigned(rand_dis(gen));
166 if (from > to)
167 swap(from, to);
168 cnt += bv.count_range(from, to, *rs); // use rs index for acceleration
169 } // for i
170 }
171 // this is mostly to prevent compiler to optimize loop away
172 std::cout << "Count range with blocks test finished." << cnt << "\r";
173 }
174
175 /// count_to() test using pre-calculated rank-select index
176 ///
177 static
178 void bv_count_to_acc(const bm::bvector<>& bv)
179 {
180 bm::bvector<>::size_type cnt = 0;
181
182 // build a block population count list, used for count_to() acceleration
183 std::unique_ptr<bm::bvector<>::rs_index_type> rs(new bm::bvector<>::rs_index_type());
184 bv.build_rs_index(rs.get());
185
186 {
187 bm::chrono_taker tt1("4. bvector<>::count_to() with rs_index", benchmark_count, &timing_map);
188
189 for (unsigned i = 0; i < benchmark_count; ++i)
190 {
191 unsigned to = unsigned(rand_dis(gen));
192 cnt += bv.count_to(to, *rs); // use rank-select index for acceleration
193 }
194 }
195 // this is mostly to prevent compiler to optimize loop away
196 std::cout << "Count to with blocks test finished." << cnt << "\r";
197 }
198
199
200 /// count_range implemented via two count_to() calls using pre-calculated
201 /// rank-select index
202 ///
203 static
204 void bv_count_to_range_acc(const bm::bvector<>& bv)
205 {
206 bm::bvector<>::size_type cnt = 0;
207
208 // build a block population count list, used for count_to() acceleration
209 std::unique_ptr<bm::bvector<>::rs_index_type> rs(new bm::bvector<>::rs_index_type());
210 bv.build_rs_index(rs.get());
211
212 {
213 bm::chrono_taker tt1("5. bvector<>::count_to to simulate count_range()", benchmark_count, &timing_map);
214
215 for (unsigned i = 0; i < benchmark_count; ++i)
216 {
217 unsigned from = unsigned(rand_dis(gen));
218 unsigned to = unsigned(rand_dis(gen));
219 if (from > to)
220 swap(from, to);
221
222 bm::bvector<>::size_type cnt_to = bv.count_to(to, *rs);
223 bm::bvector<>::size_type cnt_from = bv.count_to(from - 1, *rs);
224 bm::bvector<>::size_type cnt_r = cnt_to - cnt_from;
225 cnt += cnt_r;
226 }
227 }
228 // this is mostly to prevent compiler to optimize loop away
229 std::cout << "Count range via count_to test finished." << cnt << "\r";
230 }
231
232 /// count_range implemented via bm::count_and
233 ///
234 /// this method can be used, when we need co compute multiple ranges in one call
235 ///
236 static
237 void bv_count_and(const bm::bvector<>& bv)
238 {
239 bm::bvector<>::size_type cnt = 0;
240 {
241 bm::chrono_taker tt1("6. bm::count_and with mask vector", benchmark_count, &timing_map);
242
243 bm::bvector<> mask_bv(bm::BM_GAP); // use compressed mask, better seluts on long ranges
244 for (unsigned i = 0; i < benchmark_count; ++i)
245 {
246 unsigned from = unsigned(rand_dis(gen));
247 unsigned to = unsigned(rand_dis(gen));
248 if (from > to)
249 swap(from, to);
250
251 mask_bv.set_range(from, to, true); // set mask vector
252
253 cnt += bm::count_and(bv, mask_bv);
254 mask_bv.clear(true); // clear and free memory (faster)
255 }
256 }
257 // this is mostly to prevent compiler to optimize loop away
258 std::cout << "count AND finished." << cnt << "\r";
259 }
260
261 /// count_to implemented via bm::bvector<>::counted_enumerator
262 ///
263 /// Counted enumerator is an iterator automata, which counts the running population count
264 /// along the iteration sequence
265 ///
266 static
267 void bv_counted_enumerator(const bm::bvector<>& bv)
268 {
269 bm::bvector<>::size_type cnt = 0;
270 {
271 // This is a slow method so we use less iterators
272 bm::chrono_taker tt1("7. bm::bvector<>::counted_enumerator", benchmark_count/20, &timing_map);
273
274 for (unsigned i = 0; i < benchmark_count/20; ++i)
275 {
276 unsigned to = unsigned(rand_dis(gen));
277 bm::bvector<>::counted_enumerator en = bv.first();
278 for (; en.valid(); ++en)
279 {
280 if (*en > to)
281 break;
282 }
283 cnt += en.count();
284 }
285 }
286 std::cout << "counted_enumerator finished." << cnt << "\r";
287 }
288
289
290
291
292 int main(void)
293 {
294 try
295 {
296 bm::bvector<> bv;
297 generate_bvector(bv);
298
299 /// pre-heat CPU to minimize dynamic overclocking
300 unsigned s = pre_heat(bv);
301 std::cout << s << "\r";
302
303
304 // Test 1.
305 // Uses plain bvector<>::count() to compute global population count
306 // This function would benefit from SIMD (SSE42 / AVX2) acceleration
307 //
308 bv_count_test(bv);
309
310 // Test 2.
311 // Uses bvector<>::count_range() to compute population count in a randomly generated
312 // region of a bit-vector.
313 // This is should be naturally faster than Test 1, because it range is less than the whole
314 //
315 bv_count_range(bv);
316
317 // Test 3.
318 // Uses bvector<>::count_range() together with bvector<>::count_blocks()
319 // (pre-calculated bit-count for each block).
320 // It make sense to use this method if bit-vector is constant (or chnages infrequently)
321 // and we need to do many range counting calculations
322 //
323 bv_count_range_acc(bv);
324
325 // Test 4.
326 // Uses bvector<>::count_to() to compute population count to a specified element.
327 // Equivalent of count_range(0, to);
328 // This method uses acceleration structure using bvector<>::running_count_blocks()
329 // It is similar to count_range acceleration, but uses a different (faster) algorithm
330 //
331 bv_count_to_acc(bv);
332
333 // Test 5.
334 // Uses bvector<>::count_to() twice to simulate count_range()
335 // using counting difference:
336 // count_r = count_to(0, from) - count_to(0, to-1)
337 // This method can actually be faster than count_range()
338 //
339 bv_count_to_range_acc(bv);
340
341 // Test 6.
342 // Compute range population count via a mask vector and logical AND operation.
343 // Not the fastest method, but can be useful, when multiple ranges needs to be computed
344 //
345 bv_count_and(bv);
346
347 // Test 7.
348 // Compute cout using counted_enumerator iterator
349 // method combines iteratrion over bit vector and sliding population count
350 bv_counted_enumerator(bv);
351
352
353 // print all test timing results
354 //
355 std::cout << " "
356 << std::endl;
357
358 bm::chrono_taker::print_duration_map(timing_map, bm::chrono_taker::ct_ops_per_sec);
359 }
360 catch(std::exception& ex)
361 {
362 std::cerr << ex.what() << std::endl;
363 return 1;
364 }
365
366 return 0;
367 }
368
pre_heat
static bm::bvector ::size_type pre_heat(const bm::bvector<> &bv)
"pre-heat" CPU to minimize dynamic overclocking effects
Definition: sample11.cpp:96
bm::bvector::set_range
bvector< Alloc > & set_range(size_type left, size_type right, bool value=true)
Sets all bits in the specified closed interval [left,right] Interval must be inside the bvector's siz...
Definition: bm.h:2158
bm::bvector::calc_stat
void calc_stat(struct bm::bvector< Alloc >::statistics *st) const BMNOEXCEPT
Calculates bitvector statistics.
Definition: bm.h:3393
generate_bvector
static void generate_bvector(bm::bvector<> &bv)
generate pseudo-random bit-vector, mix of blocks
Definition: sample11.cpp:57
bm::bvector::rs_index_type
rs_index< allocator_type > rs_index_type
Definition: bm.h:831
benchmark_count
const unsigned benchmark_count
Definition: sample11.cpp:46
timing_map
bm::chrono_taker::duration_map_type timing_map
Definition: sample11.cpp:44
bm::chrono_taker
Utility class to collect performance measurements and statistics.
Definition: bmtimer.h:39
bv_counted_enumerator
static void bv_counted_enumerator(const bm::bvector<> &bv)
count_to implemented via bm::bvector<>::counted_enumerator
Definition: sample11.cpp:267
bm::bv_statistics::bit_blocks
size_t bit_blocks
Number of bit blocks.
Definition: bmfunc.h:56
BM_DECLARE_TEMP_BLOCK
#define BM_DECLARE_TEMP_BLOCK(x)
Definition: bm.h:47
bm::bvector::count_range
size_type count_range(size_type left, size_type right, const rs_index_type &rs_idx) const BMNOEXCEPT
Returns count of 1 bits in the given range [left..right] Uses rank-select index to accelerate the sea...
Definition: bm.h:2959
bv_count_to_acc
static void bv_count_to_acc(const bm::bvector<> &bv)
count_to() test using pre-calculated rank-select index
Definition: sample11.cpp:178
bv_count_test
static void bv_count_test(const bm::bvector<> &bv)
simple population count for the whole vector
Definition: sample11.cpp:113
bm::bvector::counted_enumerator::count
size_type count() const BMNOEXCEPT
Number of bits ON starting from the .
Definition: bm.h:757
vector_max
unsigned vector_max
Definition: sample11.cpp:47
bmalgo.h
Algorithms for bvector<> (main include)
bv_count_and
static void bv_count_and(const bm::bvector<> &bv)
count_range implemented via bm::count_and
Definition: sample11.cpp:237
bm::bv_statistics::gap_blocks
size_t gap_blocks
Number of GAP blocks.
Definition: bmfunc.h:57
bv_count_range_acc
static void bv_count_range_acc(const bm::bvector<> &bv)
count_range() test using pre-calculated blocks bit count
Definition: sample11.cpp:152
bm::bvector<>
bm::bvector::set
bvector< Alloc > & set(size_type n, bool val=true)
Sets bit n if val is true, clears bit n if val is false.
Definition: bm.h:3581
bm::bvector::count
size_type count() const BMNOEXCEPT
population cout (count of ON bits)
Definition: bm.h:2194
bm::bvector::iterator_base::valid
bool valid() const BMNOEXCEPT
Checks if iterator is still valid. Analog of != 0 comparison for pointers.
Definition: bm.h:280
gen
std::mt19937 gen(rand_dev())
bmtimer.h
Timing utilities for benchmarking (internal)
bm::chrono_taker::ct_ops_per_sec
@ ct_ops_per_sec
Definition: bmtimer.h:59
bm::BM_GAP
@ BM_GAP
GAP compression is ON.
Definition: bmconst.h:144
main
int main(void)
Definition: sample11.cpp:292
bm::bvector::clear
void clear(const size_type *ids, size_type ids_size, bm::sort_order so=bm::BM_UNKNOWN)
clear list of bits in this bitset
Definition: bm.h:3546
bm::chrono_taker::duration_map_type
std::map< std::string, statistics > duration_map_type
test name to duration map
Definition: bmtimer.h:65
bm::count_and
BV::size_type count_and(const BV &bv1, const BV &bv2) BMNOEXCEPT
Computes bitcount of AND operation of two bitsets.
Definition: bmalgo.h:49
bv_count_range
static void bv_count_range(const bm::bvector<> &bv)
count_range() test
Definition: sample11.cpp:131
bm::chrono_taker::print_duration_map
static void print_duration_map(const duration_map_type &dmap, format fmt=ct_time)
Definition: bmtimer.h:127
bm::bvector::build_rs_index
void build_rs_index(rs_index_type *rs_idx, bvector< Alloc > *bv_blocks=0) const
compute running total of all blocks in bit vector (rank-select index)
Definition: bm.h:2290
bm::bvector::first
enumerator first() const
Returns enumerator pointing on the first non-zero bit.
Definition: bm.h:1770
bm::bvector::size_type
bm::id_t size_type
Definition: bm.h:117
bm::bvector::counted_enumerator
Constant iterator designed to enumerate "ON" bits counted_enumerator keeps bitcount,...
Definition: bm.h:715
bv_count_to_range_acc
static void bv_count_to_range_acc(const bm::bvector<> &bv)
count_range implemented via two count_to() calls using pre-calculated rank-select index
Definition: sample11.cpp:204
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
bm::bvector::optimize
void optimize(bm::word_t *temp_block=0, optmode opt_mode=opt_compress, statistics *stat=0)
Optimize memory bitvector's memory allocation.
Definition: bm.h:3071
rand_dis
std::uniform_int_distribution rand_dis(1, int(vector_max))
bm::bvector::count_to
size_type count_to(size_type n, const rs_index_type &rs_idx) const BMNOEXCEPT
Returns count of 1 bits (population) in [0..right] range.
Definition: bm.h:2533
bm::bvector::statistics
Statistical information about bitset's memory allocation details.
Definition: bm.h:121
rand_dev
std::random_device rand_dev
Definition: sample11.cpp:49