Skip to content
Navigation Menu
{{ message }}
-
Notifications
You must be signed in to change notification settings - Fork 255
Expand file tree
/
Copy pathsudoku.cpp
More file actions
460 lines (430 loc) · 14.4 KB
/
Copy pathsudoku.cpp
File metadata and controls
460 lines (430 loc) · 14.4 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
/*
Copyright (c) 2005-2021 Intel Corporation
Copyright (c) Facebook, Inc. and its affiliates.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
Copyright 2026 NVIDIA Corp.
*/
// This sudoku code was originally taken from TBB examples/thread_group/sudoku. The TBB
// example leaks: https://github.com/oneapi-src/oneTBB/issues/568. The code was modified
// by Kirk Shoop to use libunifex instead of TBB and to remove the leaks. The code was
// later modified by David Olsen to use stdexec instead of libunifex to be a test in the
// NVHPC test suite for stdexec.
#include <cstdio>
#include <cstdlib>
#include <atomic>
#include <cassert>
#include <chrono>
#include <string_view>
#include <tuple>
#include <vector>
#include <stdexec/execution.hpp>
unsigned const BOARD_SIZE = 81;
unsigned const BOARD_DIM = 9;
std::atomic<unsigned> nSols;
std::atomic<unsigned> nTasks;
std::atomic<unsigned> nRaces;
bool find_one = false;
bool verbose = false;
unsigned short init_values0[BOARD_SIZE] = {1, 0, 0, 9, 0, 0, 0, 8, 0, //
0, 8, 0, 2, 0, 0, 0, 0, 0, //
0, 0, 5, 0, 0, 0, 7, 0, 0, //
0, 5, 2, 1, 0, 0, 4, 0, 0, //
0, 0, 0, 0, 0, 5, 0, 0, 7, //
4, 0, 0, 7, 0, 0, 0, 3, 0, //
0, 3, 0, 0, 0, 2, 0, 0, 5, //
0, 0, 0, 0, 0, 0, 1, 0, 0, //
5, 0, 0, 0, 1, 0, 0, 0, 0};
unsigned short init_values1[BOARD_SIZE] = {2, 0, 1, 0, 0, 0, 0, 8, 0, //
0, 8, 0, 2, 1, 9, 6, 0, 0, //
0, 0, 5, 0, 0, 0, 7, 0, 0, //
0, 5, 2, 1, 0, 0, 4, 0, 0, //
0, 0, 0, 0, 0, 5, 0, 0, 7, //
4, 0, 0, 7, 0, 0, 0, 3, 0, //
0, 3, 0, 0, 0, 2, 0, 0, 5, //
0, 0, 0, 0, 3, 0, 1, 0, 0, //
5, 0, 0, 0, 8, 0, 0, 0, 6};
unsigned short init_values2[BOARD_SIZE] = {1, 0, 0, 9, 0, 0, 0, 8, 0, //
0, 0, 0, 2, 0, 0, 0, 0, 0, //
0, 0, 5, 0, 0, 0, 7, 0, 0, //
0, 5, 2, 6, 0, 0, 4, 0, 0, //
0, 0, 0, 0, 0, 5, 0, 0, 7, //
4, 0, 0, 7, 0, 0, 0, 3, 0, //
0, 3, 0, 0, 0, 2, 0, 0, 5, //
0, 0, 0, 0, 0, 0, 1, 0, 0, //
5, 0, 0, 0, 1, 0, 0, 0, 0};
unsigned short init_values3[BOARD_SIZE] = {1, 0, 0, 9, 0, 0, 0, 8, 0, //
0, 0, 0, 2, 0, 0, 0, 0, 0, //
0, 0, 5, 0, 0, 0, 7, 0, 0, //
0, 0, 2, 6, 0, 0, 0, 0, 0, //
0, 0, 0, 0, 0, 5, 0, 0, 7, //
4, 0, 0, 0, 0, 0, 0, 3, 0, //
0, 3, 0, 0, 0, 2, 0, 0, 5, //
0, 0, 0, 0, 0, 0, 1, 0, 0, //
5, 0, 0, 0, 1, 0, 0, 0, 0};
unsigned short *all_init_values[] = {init_values0, init_values1, init_values2, init_values3};
struct board_element
{
unsigned short solved_element;
unsigned potential_set;
};
void print_board(board_element *b)
{
for (unsigned row = 0; row < BOARD_DIM; ++row)
{
for (unsigned col = 0; col < BOARD_DIM; ++col)
{
printf(" %d", b[row * BOARD_DIM + col].solved_element);
if (col == 2 || col == 5)
printf(" |");
}
printf("\n");
if (row == 2 || row == 5)
printf(" ---------------------\n");
}
}
void print_potential_board(board_element *b)
{
for (unsigned row = 0; row < BOARD_DIM; ++row)
{
for (unsigned col = 0; col < BOARD_DIM; ++col)
{
if (b[row * BOARD_DIM + col].solved_element)
printf(" %4d ", b[row * BOARD_DIM + col].solved_element);
else
printf(" [%4d]", b[row * BOARD_DIM + col].potential_set);
if (col == 2 || col == 5)
printf(" |");
}
printf("\n");
if (row == 2 || row == 5)
printf(" ----------------------------------------------------------------"
"--\n");
}
}
void init_board(board_element *b)
{
for (unsigned i = 0; i < BOARD_SIZE; ++i)
b[i].solved_element = b[i].potential_set = 0;
}
void init_board(board_element *b, unsigned short const arr[81])
{
for (unsigned i = 0; i < BOARD_SIZE; ++i)
{
b[i].solved_element = arr[i];
b[i].potential_set = 0;
}
}
void init_potentials(board_element *b)
{
for (unsigned i = 0; i < BOARD_SIZE; ++i)
b[i].potential_set = 0;
}
void copy_board(board_element *src, board_element *dst)
{
for (unsigned i = 0; i < BOARD_SIZE; ++i)
dst[i].solved_element = src[i].solved_element;
}
bool fixed_board(board_element *b)
{
for (int i = BOARD_SIZE - 1; i >= 0; --i)
if (b[i].solved_element == 0)
return false;
return true;
}
bool in_row(board_element *b, unsigned row, unsigned col, unsigned short p)
{
for (unsigned c = 0; c < BOARD_DIM; ++c)
if (c != col && b[row * BOARD_DIM + c].solved_element == p)
return true;
return false;
}
bool in_col(board_element *b, unsigned row, unsigned col, unsigned short p)
{
for (unsigned r = 0; r < BOARD_DIM; ++r)
if (r != row && b[r * BOARD_DIM + col].solved_element == p)
return true;
return false;
}
bool in_block(board_element *b, unsigned row, unsigned col, unsigned short p)
{
unsigned b_row = row / 3 * 3, b_col = col / 3 * 3;
for (unsigned i = b_row; i < b_row + 3; ++i)
for (unsigned j = b_col; j < b_col + 3; ++j)
if (!(i == row && j == col) && b[i * BOARD_DIM + j].solved_element == p)
return true;
return false;
}
void calculate_potentials(board_element *b)
{
for (unsigned i = 0; i < BOARD_SIZE; ++i)
{
b[i].potential_set = 0;
if (!b[i].solved_element)
{ // element is not yet fixed
unsigned row = i / BOARD_DIM, col = i % BOARD_DIM;
for (unsigned potential = 1; potential <= BOARD_DIM; ++potential)
{
if (!in_row(b, row, col, potential) && !in_col(b, row, col, potential)
&& !in_block(b, row, col, potential))
b[i].potential_set |= 1 << (potential - 1);
}
}
}
}
bool valid_board(board_element *b)
{
bool success = true;
for (unsigned i = 0; i < BOARD_SIZE; ++i)
{
if (success && b[i].solved_element)
{ // element is fixed
unsigned row = i / BOARD_DIM, col = i % BOARD_DIM;
if (in_row(b, row, col, b[i].solved_element) || in_col(b, row, col, b[i].solved_element)
|| in_block(b, row, col, b[i].solved_element))
success = false;
}
}
return success;
}
bool examine_potentials(board_element *b, bool *progress)
{
bool singletons = false;
for (unsigned i = 0; i < BOARD_SIZE; ++i)
{
if (b[i].solved_element == 0 && b[i].potential_set == 0) // empty set
return false;
switch (b[i].potential_set)
{
case 1:
{
b[i].solved_element = 1;
singletons = true;
break;
}
case 2:
{
b[i].solved_element = 2;
singletons = true;
break;
}
case 4:
{
b[i].solved_element = 3;
singletons = true;
break;
}
case 8:
{
b[i].solved_element = 4;
singletons = true;
break;
}
case 16:
{
b[i].solved_element = 5;
singletons = true;
break;
}
case 32:
{
b[i].solved_element = 6;
singletons = true;
break;
}
case 64:
{
b[i].solved_element = 7;
singletons = true;
break;
}
case 128:
{
b[i].solved_element = 8;
singletons = true;
break;
}
case 256:
{
b[i].solved_element = 9;
singletons = true;
break;
}
default:
{
assert(!"potential set is not a power of 2");
break;
}
}
}
*progress = singletons;
return valid_board(b);
}
void spawn_partial_solve(stdexec::parallel_scheduler sch,
stdexec::simple_counting_scope &scope,
stdexec::inplace_stop_source &stop,
std::unique_ptr<board_element[]> board,
unsigned first_potential_set);
void partial_solve(stdexec::parallel_scheduler sch,
stdexec::simple_counting_scope &scope,
stdexec::inplace_stop_source &stop,
std::unique_ptr<board_element[]> board,
unsigned first_potential_set)
{
if (stop.stop_requested())
{
++nRaces;
return;
}
if (fixed_board(board.get()))
{
if (++nSols == 1 && verbose)
{
print_board(board.get());
}
if (find_one)
{
stop.request_stop();
}
return;
}
calculate_potentials(board.get());
bool progress = true;
bool success = examine_potentials(board.get(), &progress);
if (success && progress)
{
partial_solve(sch, scope, stop, std::move(board), first_potential_set);
return;
}
else if (success && !progress)
{
while (board.get()[first_potential_set].solved_element != 0)
{
++first_potential_set;
}
auto potential_board =
[=, &scope, &stop, board = std::move(board)](unsigned short potential) mutable noexcept
{
if (1 << (potential - 1) & board.get()[first_potential_set].potential_set)
{
// NOLINTNEXTLINE(bugprone-unhandled-exception-at-new)
std::unique_ptr<board_element[]> new_board(new board_element[BOARD_SIZE]);
copy_board(board.get(), new_board.get());
new_board.get()[first_potential_set].solved_element = potential;
spawn_partial_solve(sch, scope, stop, std::move(new_board), first_potential_set);
}
};
for (int i = 1; i < 10; ++i)
{
potential_board(i);
}
}
}
void spawn_partial_solve(stdexec::parallel_scheduler sch,
stdexec::simple_counting_scope &scope,
stdexec::inplace_stop_source &stop,
std::unique_ptr<board_element[]> board,
unsigned first_potential_set)
{
stdexec::spawn(stdexec::schedule(sch)
| stdexec::then(
[=, &scope, &stop, board = std::move(board)]() mutable noexcept
{
++nTasks;
partial_solve(sch, scope, stop, std::move(board), first_potential_set);
})
| stdexec::upon_error([](auto) noexcept {}), // no-op, just swallow errors
scope.get_token());
}
std::tuple<unsigned, unsigned, unsigned, std::chrono::steady_clock::duration>
solve(stdexec::parallel_scheduler sch, unsigned short const *init_values)
{
nSols = 0;
nTasks = 0;
nRaces = 0;
std::unique_ptr<board_element[]> start_board{new board_element[BOARD_SIZE]};
init_board(start_board.get(), init_values);
auto start = std::chrono::steady_clock::now();
stdexec::inplace_stop_source stop;
auto canceled = []()
{
if (verbose)
{
printf("\ncanceled \n\n");
}
};
stdexec::inplace_stop_token::template callback_type<decltype(canceled)> callback(stop.get_token(),
canceled);
stdexec::simple_counting_scope scope;
spawn_partial_solve(sch, scope, stop, std::move(start_board), 0);
stdexec::sync_wait(scope.join());
return std::make_tuple((unsigned) nSols,
(unsigned) nTasks,
(unsigned) nRaces,
std::chrono::steady_clock::now() - start);
}
using double_sec = std::chrono::duration<double>;
int main(int argc, char *argv[])
{
bool silent = false;
std::vector<std::string_view> args(argv + 1, argv + argc);
for (auto arg: args)
{
if (arg == "find-one")
{
find_one = true;
}
else if (arg == "verbose")
{
verbose = true;
}
else if (arg == "silent")
{
silent = true;
}
else
{
printf("unrecognized argument: -> %.*s", (int) arg.size(), arg.data());
}
}
if (silent)
verbose = false;
auto one_solve = [&](unsigned short const *init_values)
{
auto [number, tasks, races, solve_time] = solve(stdexec::get_parallel_scheduler(), init_values);
if (!silent)
{
if (find_one)
{
printf("Sudoku: Time for first solution using %5u tasks with %5u "
"races: %9.6fs\n",
tasks,
races,
std::chrono::duration_cast<double_sec>(solve_time).count());
}
else
{
printf("Sudoku: Time for all %6u solutions using %7u tasks: %9.6fs\n",
number,
tasks,
std::chrono::duration_cast<double_sec>(solve_time).count());
}
}
fflush(stdout);
};
for (int iv = 0; iv < 4; ++iv)
{
unsigned short const *init_values = all_init_values[iv];
find_one = false;
one_solve(init_values);
find_one = true;
one_solve(init_values);
}
}
You can’t perform that action at this time.