Skip to main content
`Ctrl`+`K`

# /build/rocrand-D7zBeW/rocrand-7.2.4/library/include/rocrand/rocrand_sobol64.h Source File

API library: /build/rocrand-D7zBeW/rocrand-7.2.4/library/include/rocrand/rocrand_sobol64.h Source File
rocrand_sobol64.h
1// Copyright (c) 2021-2025 Advanced Micro Devices, Inc. All rights reserved.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a copy
4// of this software and associated documentation files (the "Software"), to deal
5// in the Software without restriction, including without limitation the rights
6// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7// copies of the Software, and to permit persons to whom the Software is
8// furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19// THE SOFTWARE.
20
21#ifndef ROCRAND_SOBOL64_H_
22#define ROCRAND_SOBOL64_H_
23
24#include <hip/hip_runtime.h>
25
26 namespace rocrand_device {
27
28 template<bool UseSharedVectors>
29 struct sobol64_state
30{
31 unsigned long long int d;
32 unsigned long long int i;
33 unsigned long long int vectors[64];
34
35 __forceinline__ __device__ __host__ sobol64_state() : d(), i(), vectors() {}
36
37 __forceinline__ __device__ __host__ sobol64_state(const unsigned long long int d,
38 const unsigned long long int i,
39 const unsigned long long int* vectors)
40 : d(d), i(i)
41 {
42 for(int k = 0; k < 64; k++)
43 {
44 this->vectors[k] = vectors[k];
45 }
46 }
47};
48
49 template<>
50 struct sobol64_state<true>
51{
52 unsigned long long int d;
53 unsigned long long int i;
54 const unsigned long long int * vectors;
55
56 __forceinline__ __device__ __host__ sobol64_state() : d(), i(), vectors() {}
57
58 __forceinline__ __device__ __host__ sobol64_state(const unsigned long long int d,
59 const unsigned long long int i,
60 const unsigned long long int* vectors)
61 : d(d), i(i), vectors(vectors)
62 {}
63};
64
65 template<bool UseSharedVectors>
66 class sobol64_engine
67{
68 public:
69
70 typedef struct sobol64_state<UseSharedVectors> sobol64_state;
71
72 __forceinline__ __device__ __host__ sobol64_engine() {}
73
74 __forceinline__ __device__ __host__ sobol64_engine(const unsigned long long int* vectors,
75 const unsigned long long int offset)
76 : m_state(0, 0, vectors)
77 {
78 discard_state(offset);
79 }
80
82 __forceinline__ __device__ __host__ void discard(unsigned long long int offset)
83 {
84 discard_state(offset);
85 }
86
87 __forceinline__ __device__ __host__ void discard()
88 {
89 discard_state();
90 }
91
93 __forceinline__ __device__ __host__ void discard_stride(unsigned long long int stride)
94 {
95 discard_state_power2(stride);
96 }
97
98 __forceinline__ __device__ __host__ unsigned long long int operator()()
99 {
100 return this->next();
101 }
102
103 __forceinline__ __device__ __host__ unsigned long long int next()
104 {
105 unsigned long long int p = m_state.d;
106 discard_state();
107 return p;
108 }
109
110 __forceinline__ __device__ __host__ unsigned long long int current() const
111 {
112 return m_state.d;
113 }
114
115 __forceinline__ __device__ __host__ static constexpr bool uses_shared_vectors()
116 {
117 return UseSharedVectors;
118 }
119
120 protected:
121 // Advances the internal state by offset times.
122 __forceinline__ __device__ __host__ void discard_state(unsigned long long int offset)
123 {
124 m_state.i += offset;
125 const unsigned long long int g = m_state.i ^ (m_state.i >> 1ull);
126 m_state.d = 0;
127 for(int i = 0; i < 64; i++)
128 {
129 m_state.d ^= (g & (1ull << i) ? m_state.vectors[i] : 0ull);
130 }
131 }
132
133 // Advances the internal state to the next state
134 __forceinline__ __device__ __host__ void discard_state()
135 {
136 m_state.d ^= m_state.vectors[rightmost_zero_bit(m_state.i)];
137 m_state.i++;
138 }
139
140 __forceinline__ __device__ __host__ void discard_state_power2(unsigned long long int stride)
141 {
142 // Leap frog
143 //
144 // T Bradley, J Toit, M Giles, R Tong, P Woodhams
145 // Parallelisation Techniques for Random Number Generators
146 // GPU Computing Gems, 2011
147 //
148 // For power of 2 jumps only 2 bits in Gray code change values
149 // All bits lower than log2(stride) flip 2, 4... times, i.e.
150 // do not change their values.
151
152 // log2(stride) bit
153 m_state.d ^= m_state.vectors[rightmost_zero_bit(~stride) - 1];
154 // the rightmost zero bit of i, not including the lower log2(stride) bits
155 m_state.d ^= m_state.vectors[rightmost_zero_bit(m_state.i | (stride - 1))];
156 m_state.i += stride;
157 }
158
159 // Returns the index of the rightmost zero bit in the binary expansion of
160 // x (Gray code of the current element's index)
161 // NOTE changing unsigned long long int to unit64_t will cause compile failure on device
162 __forceinline__ __device__ __host__ unsigned int rightmost_zero_bit(unsigned long long int x)
163 {
164 #if defined(__HIP_DEVICE_COMPILE__)
165 unsigned int z = __ffsll(~x);
166 return z ? z - 1 : 0;
167 #else
168 if(x == 0)
169 return 0;
170 unsigned long long int y = x;
171 unsigned long long int z = 1;
172 while(y & 1)
173 {
174 y >>= 1;
175 z++;
176 }
177 return z - 1;
178 #endif
179 }
180
181 protected:
182 // State
183 sobol64_state m_state;
184
185}; // sobol64_engine class
186
187} // end namespace rocrand_device
188
193
195 typedef rocrand_device::sobol64_engine<false> rocrand_state_sobol64;
197
208__forceinline__ __device__ __host__
209 void rocrand_init(const unsigned long long int* vectors,
210 const unsigned int offset,
211 rocrand_state_sobol64* state)
212{
213 *state = rocrand_state_sobol64(vectors, offset);
214}
215
228__forceinline__ __device__ __host__
229 unsigned long long int rocrand(rocrand_state_sobol64* state)
230{
231 return state->next();
232}
233
242__forceinline__ __device__ __host__
243 void skipahead(unsigned long long int offset, rocrand_state_sobol64* state)
244{
245 return state->discard(offset);
246}
247 // end of group rocranddevice
249
250#endif // ROCRAND_sobol64_H_
rocrand
__forceinline__ __device__ __host__ unsigned long long int rocrand(rocrand_state_sobol64 *state)
Returns uniformly distributed random unsigned long long int value from [0; 2^64 - 1] range.
Definition rocrand_sobol64.h:229
skipahead
__forceinline__ __device__ __host__ void skipahead(unsigned long long int offset, rocrand_state_sobol64 *state)
Updates sobol64 state to skip ahead by offset elements.
Definition rocrand_sobol64.h:243
rocrand_init
__forceinline__ __device__ __host__ void rocrand_init(const unsigned long long int *vectors, const unsigned int offset, rocrand_state_sobol64 *state)
Initialize sobol64 state.
Definition rocrand_sobol64.h:209