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API library: /home/docs/checkouts/readthedocs.org/user_builds/advanced-micro-devices-rocrand/checkouts/docs-6.1.2/library/include/rocrand/rocrand_philox4x32_10.h Source File
API library
rocrand_philox4x32_10.h
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52 
53 #ifndef ROCRAND_PHILOX4X32_10_H_
54 #define ROCRAND_PHILOX4X32_10_H_
55 
56 #ifndef FQUALIFIERS
57 #define FQUALIFIERS __forceinline__ __device__
58 #endif // FQUALIFIERS_
59 
60 #include "rocrand/rocrand_common.h"
61 
62 // Constants from Random123
63 // See https://www.deshawresearch.com/resources_random123.html
64 #define ROCRAND_PHILOX_M4x32_0 0xD2511F53U
65 #define ROCRAND_PHILOX_M4x32_1 0xCD9E8D57U
66 #define ROCRAND_PHILOX_W32_0 0x9E3779B9U
67 #define ROCRAND_PHILOX_W32_1 0xBB67AE85U
68 
77 #define ROCRAND_PHILOX4x32_DEFAULT_SEED 0xdeadbeefdeadbeefULL // end of group rocranddevice
79 
80 namespace rocrand_device {
81 namespace detail {
82 
84 unsigned int mulhilo32(unsigned int x, unsigned int y, unsigned int& z)
85 {
86  unsigned long long xy = mad_u64_u32(x, y, 0);
87  z = static_cast<unsigned int>(xy >> 32);
88  return static_cast<unsigned int>(xy);
89 }
90 
91 } // end detail namespace
92 
93 class philox4x32_10_engine
94 {
95 public:
96  struct philox4x32_10_state
97  {
98  uint4 counter;
99  uint4 result;
100  uint2 key;
101  unsigned int substate;
102 
103  #ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
104  // The Box–Muller transform requires two inputs to convert uniformly
105  // distributed real values [0; 1] to normally distributed real values
106  // (with mean = 0, and stddev = 1). Often user wants only one
107  // normally distributed number, to save performance and random
108  // numbers the 2nd value is saved for future requests.
109  unsigned int boxmuller_float_state; // is there a float in boxmuller_float
110  unsigned int boxmuller_double_state; // is there a double in boxmuller_double
111  float boxmuller_float; // normally distributed float
112  double boxmuller_double; // normally distributed double
113  #endif
114  };
115 
117  philox4x32_10_engine()
118  {
119  this->seed(ROCRAND_PHILOX4x32_DEFAULT_SEED, 0, 0);
120  }
121 
128  philox4x32_10_engine(const unsigned long long seed,
129  const unsigned long long subsequence,
130  const unsigned long long offset)
131  {
132  this->seed(seed, subsequence, offset);
133  }
134 
141  void seed(unsigned long long seed_value,
142  const unsigned long long subsequence,
143  const unsigned long long offset)
144  {
145  m_state.key.x = static_cast<unsigned int>(seed_value);
146  m_state.key.y = static_cast<unsigned int>(seed_value >> 32);
147  this->restart(subsequence, offset);
148  }
149 
152  void discard(unsigned long long offset)
153  {
154  this->discard_impl(offset);
155  this->m_state.result = this->ten_rounds(m_state.counter, m_state.key);
156  }
157 
163  void discard_subsequence(unsigned long long subsequence)
164  {
165  this->discard_subsequence_impl(subsequence);
166  m_state.result = this->ten_rounds(m_state.counter, m_state.key);
167  }
168 
170  void restart(const unsigned long long subsequence,
171  const unsigned long long offset)
172  {
173  m_state.counter = {0, 0, 0, 0};
174  m_state.result = {0, 0, 0, 0};
175  m_state.substate = 0;
176  #ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
177  m_state.boxmuller_float_state = 0;
178  m_state.boxmuller_double_state = 0;
179  #endif
180  this->discard_subsequence_impl(subsequence);
181  this->discard_impl(offset);
182  m_state.result = this->ten_rounds(m_state.counter, m_state.key);
183  }
184 
186  unsigned int operator()()
187  {
188  return this->next();
189  }
190 
192  unsigned int next()
193  {
194  #if defined(__HIP_PLATFORM_AMD__)
195  unsigned int ret = m_state.result.data[m_state.substate];
196  #else
197  unsigned int ret = (&m_state.result.x)[m_state.substate];
198  #endif
199  m_state.substate++;
200  if(m_state.substate == 4)
201  {
202  m_state.substate = 0;
203  this->discard_state();
204  m_state.result = this->ten_rounds(m_state.counter, m_state.key);
205  }
206  return ret;
207  }
208 
210  uint4 next4()
211  {
212  uint4 ret = m_state.result;
213  this->discard_state();
214  m_state.result = this->ten_rounds(m_state.counter, m_state.key);
215  return this->interleave(ret, m_state.result);
216  }
217 
218 protected:
219  // Advances the internal state to skip \p offset numbers.
220  // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
222  void discard_impl(unsigned long long offset)
223  {
224  // Adjust offset for subset
225  m_state.substate += offset & 3;
226  unsigned long long counter_offset = offset / 4;
227  counter_offset += m_state.substate < 4 ? 0 : 1;
228  m_state.substate += m_state.substate < 4 ? 0 : -4;
229  // Discard states
230  this->discard_state(counter_offset);
231  }
232 
233  // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
235  void discard_subsequence_impl(unsigned long long subsequence)
236  {
237  unsigned int lo = static_cast<unsigned int>(subsequence);
238  unsigned int hi = static_cast<unsigned int>(subsequence >> 32);
239 
240  unsigned int temp = m_state.counter.z;
241  m_state.counter.z += lo;
242  m_state.counter.w += hi + (m_state.counter.z < temp ? 1 : 0);
243  }
244 
245  // Advances the internal state by offset times.
246  // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
248  void discard_state(unsigned long long offset)
249  {
250  unsigned int lo = static_cast<unsigned int>(offset);
251  unsigned int hi = static_cast<unsigned int>(offset >> 32);
252 
253  uint4 temp = m_state.counter;
254  m_state.counter.x += lo;
255  m_state.counter.y += hi + (m_state.counter.x < temp.x ? 1 : 0);
256  m_state.counter.z += (m_state.counter.y < temp.y ? 1 : 0);
257  m_state.counter.w += (m_state.counter.z < temp.z ? 1 : 0);
258  }
259 
260  // Advances the internal state to the next state
261  // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
263  void discard_state()
264  {
265  m_state.counter = this->bump_counter(m_state.counter);
266  }
267 
269  static uint4 bump_counter(uint4 counter)
270  {
271  counter.x++;
272  unsigned int add = counter.x == 0 ? 1 : 0;
273  counter.y += add; add = counter.y == 0 ? add : 0;
274  counter.z += add; add = counter.z == 0 ? add : 0;
275  counter.w += add;
276  return counter;
277  }
278 
280  uint4 interleave(const uint4 prev, const uint4 next) const
281  {
282  switch(m_state.substate)
283  {
284  case 0:
285  return prev;
286  case 1:
287  return uint4{ prev.y, prev.z, prev.w, next.x };
288  case 2:
289  return uint4{ prev.z, prev.w, next.x, next.y };
290  case 3:
291  return uint4{ prev.w, next.x, next.y, next.z };
292  }
293  __builtin_unreachable();
294  }
295 
296  // 10 Philox4x32 rounds
298  uint4 ten_rounds(uint4 counter, uint2 key)
299  {
300  counter = this->single_round(counter, key); key = this->bumpkey(key); // 1
301  counter = this->single_round(counter, key); key = this->bumpkey(key); // 2
302  counter = this->single_round(counter, key); key = this->bumpkey(key); // 3
303  counter = this->single_round(counter, key); key = this->bumpkey(key); // 4
304  counter = this->single_round(counter, key); key = this->bumpkey(key); // 5
305  counter = this->single_round(counter, key); key = this->bumpkey(key); // 6
306  counter = this->single_round(counter, key); key = this->bumpkey(key); // 7
307  counter = this->single_round(counter, key); key = this->bumpkey(key); // 8
308  counter = this->single_round(counter, key); key = this->bumpkey(key); // 9
309  return this->single_round(counter, key); // 10
310  }
311 
312 private:
313  // Single Philox4x32 round
315  static uint4 single_round(uint4 counter, uint2 key)
316  {
317  // Source: Random123
318  unsigned int hi0;
319  unsigned int hi1;
320  unsigned int lo0 = detail::mulhilo32(ROCRAND_PHILOX_M4x32_0, counter.x, hi0);
321  unsigned int lo1 = detail::mulhilo32(ROCRAND_PHILOX_M4x32_1, counter.z, hi1);
322  return uint4 {
323  hi1 ^ counter.y ^ key.x,
324  lo1,
325  hi0 ^ counter.w ^ key.y,
326  lo0
327  };
328  }
329 
331  static uint2 bumpkey(uint2 key)
332  {
333  key.x += ROCRAND_PHILOX_W32_0;
334  key.y += ROCRAND_PHILOX_W32_1;
335  return key;
336  }
337 
338 protected:
339  // State
340  philox4x32_10_state m_state;
341 
342  #ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
343  friend struct detail::engine_boxmuller_helper<philox4x32_10_engine>;
344  #endif
345 
346 }; // philox4x32_10_engine class
347 
348 } // end namespace rocrand_device
349 
356 typedef rocrand_device::philox4x32_10_engine rocrand_state_philox4x32_10;
358 
371 void rocrand_init(const unsigned long long seed,
372  const unsigned long long subsequence,
373  const unsigned long long offset,
374  rocrand_state_philox4x32_10 * state)
375 {
376  *state = rocrand_state_philox4x32_10(seed, subsequence, offset);
377 }
378 
392 unsigned int rocrand(rocrand_state_philox4x32_10 * state)
393 {
394  return state->next();
395 }
396 
410 uint4 rocrand4(rocrand_state_philox4x32_10 * state)
411 {
412  return state->next4();
413 }
414 
424 void skipahead(unsigned long long offset, rocrand_state_philox4x32_10 * state)
425 {
426  return state->discard(offset);
427 }
428 
439 void skipahead_subsequence(unsigned long long subsequence, rocrand_state_philox4x32_10 * state)
440 {
441  return state->discard_subsequence(subsequence);
442 }
443 
454  void skipahead_sequence(unsigned long long sequence, rocrand_state_philox4x32_10 * state)
455  {
456  return state->discard_subsequence(sequence);
457  }
458 
459 #endif // ROCRAND_PHILOX4X32_10_H_
460  // end of group rocranddevice
FQUALIFIERS unsigned int rocrand(rocrand_state_philox4x32_10 *state)
Returns uniformly distributed random unsigned int value from [0; 2^32 - 1] range.
Definition: rocrand_philox4x32_10.h:392
#define ROCRAND_PHILOX4x32_DEFAULT_SEED
Default seed for PHILOX4x32 PRNG.
Definition: rocrand_philox4x32_10.h:77
FQUALIFIERS void skipahead_subsequence(unsigned long long subsequence, rocrand_state_philox4x32_10 *state)
Updates Philox state to skip ahead by subsequence subsequences.
Definition: rocrand_philox4x32_10.h:439
FQUALIFIERS void skipahead_sequence(unsigned long long sequence, rocrand_state_philox4x32_10 *state)
Updates Philox state to skip ahead by sequence sequences.
Definition: rocrand_philox4x32_10.h:454
FQUALIFIERS uint4 rocrand4(rocrand_state_philox4x32_10 *state)
Returns four uniformly distributed random unsigned int values from [0; 2^32 - 1] range.
Definition: rocrand_philox4x32_10.h:410
FQUALIFIERS void rocrand_init(const unsigned long long seed, const unsigned long long subsequence, const unsigned long long offset, rocrand_state_philox4x32_10 *state)
Initializes Philox state.
Definition: rocrand_philox4x32_10.h:371
FQUALIFIERS void skipahead(unsigned long long offset, rocrand_state_philox4x32_10 *state)
Updates Philox state to skip ahead by offset elements.
Definition: rocrand_philox4x32_10.h:424
#define FQUALIFIERS
Shorthand for commonly used function qualifiers.
Definition: rocrand_uniform.h:31