1 | // |
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2 | // Cforall Version 1.0.0 Copyright (C) 2022 University of Waterloo |
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3 | // |
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4 | // The contents of this file are covered under the licence agreement in the |
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5 | // file "LICENCE" distributed with Cforall. |
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6 | // |
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7 | // random.hfa -- |
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8 | // |
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9 | // Author : Peter A. Buhr |
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10 | // Created On : Fri Jan 14 07:18:11 2022 |
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11 | // Last Modified By : Peter A. Buhr |
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12 | // Last Modified On : Mon Nov 21 17:50:12 2022 |
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13 | // Update Count : 15 |
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14 | // |
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15 | |
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16 | #pragma once |
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17 | |
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18 | #include <stdint.h> |
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19 | |
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20 | // Set default PRNG for architecture size. |
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21 | #ifdef __x86_64__ // 64-bit architecture |
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22 | #define LEHMER64 |
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23 | #else // 32-bit architecture |
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24 | #define XORSHIFT_6_21_7 |
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25 | #endif // __x86_64__ |
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26 | |
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27 | // C/CFA PRNG name and random-state. |
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28 | #ifdef LEHMER64 |
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29 | #define PRNG_NAME lehmer64 |
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30 | #define PRNG_ARG_T __uint128_t |
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31 | #endif // LEHMER64 |
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32 | |
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33 | #ifdef XORSHIFT_6_21_7 |
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34 | #define PRNG_NAME xorshift_6_21_7 |
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35 | #define PRNG_ARG_T uint32_t |
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36 | #endif // XORSHIFT_6_21_7 |
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37 | |
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38 | #ifdef __cforall // don't include in C code (invoke.h) |
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39 | |
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40 | // Pipelined to allow out-of-order overlap with reduced dependencies. Critically, the current random state is returned |
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41 | // (copied), and then compute and store the next random value. |
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42 | |
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43 | #if defined(__SIZEOF_INT128__) |
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44 | //-------------------------------------------------- |
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45 | static inline uint64_t lehmer64( __uint128_t & state ) { |
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46 | __uint128_t ret = state; |
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47 | state *= 0xda942042e4dd58b5; |
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48 | return ret >> 64; |
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49 | } |
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50 | |
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51 | //-------------------------------------------------- |
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52 | static inline uint64_t wyhash64( uint64_t & state ) { |
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53 | state += 0x60bee2bee120fc15; |
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54 | __uint128_t tmp; |
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55 | tmp = (__uint128_t) state * 0xa3b195354a39b70d; |
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56 | uint64_t m1 = (tmp >> 64) ^ tmp; |
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57 | tmp = (__uint128_t)m1 * 0x1b03738712fad5c9; |
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58 | uint64_t m2 = (tmp >> 64) ^ tmp; |
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59 | return m2; |
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60 | } |
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61 | #endif |
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62 | |
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63 | //-------------------------------------------------- |
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64 | static inline uint64_t xorshift_13_7_17( uint64_t & state ) { |
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65 | uint64_t ret = state; |
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66 | state ^= state << 13; |
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67 | state ^= state >> 7; |
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68 | state ^= state << 17; |
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69 | return ret; |
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70 | } |
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71 | |
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72 | //-------------------------------------------------- |
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73 | static inline uint32_t xorshift_6_21_7( uint32_t & state ) { |
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74 | uint32_t ret = state; |
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75 | state ^= state << 6; |
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76 | state ^= state >> 21; |
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77 | state ^= state << 7; |
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78 | return ret; |
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79 | } // xorshift_6_21_7 |
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80 | |
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81 | //-------------------------------------------------- |
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82 | typedef struct { |
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83 | uint32_t a, b, c, d; |
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84 | uint32_t counter; |
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85 | } xorwow__state_t; |
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86 | |
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87 | // The state array must be initialized to not be all zero in the first four words. |
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88 | static inline uint32_t xorwow( xorwow__state_t & state ) { |
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89 | // Algorithm "xorwow" from p. 5 of Marsaglia, "Xorshift RNGs". |
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90 | uint32_t ret = state.a + state.counter; |
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91 | uint32_t t = state.d; |
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92 | |
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93 | uint32_t const s = state.a; |
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94 | state.d = state.c; |
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95 | state.c = state.b; |
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96 | state.b = s; |
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97 | |
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98 | t ^= t >> 2; |
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99 | t ^= t << 1; |
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100 | t ^= s ^ (s << 4); |
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101 | state.a = t; |
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102 | |
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103 | state.counter += 362437; |
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104 | return ret; |
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105 | } |
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106 | |
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107 | //-------------------------------------------------- |
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108 | static inline uint32_t LCG( uint32_t & state ) { // linear congruential generator |
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109 | uint32_t ret = state; |
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110 | state = 36969 * (state & 65535) + (state >> 16); // 36969 is NOT prime! No not change it! |
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111 | return ret; |
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112 | } // LCG |
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113 | |
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114 | //-------------------------------------------------- |
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115 | #define M (1_l64u << 48_l64u) |
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116 | #define A (25214903917_l64u) |
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117 | #define AI (18446708753438544741_l64u) |
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118 | #define C (11_l64u) |
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119 | #define D (16_l64u) |
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120 | |
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121 | // Bi-directional LCG random-number generator |
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122 | static inline uint32_t LCGBI_fwd( uint64_t & state ) { |
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123 | state = (A * state + C) & (M - 1); |
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124 | return state >> D; |
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125 | } |
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126 | |
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127 | static inline uint32_t LCGBI_bck( uint64_t & state ) { |
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128 | unsigned int r = state >> D; |
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129 | state = AI * (state - C) & (M - 1); |
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130 | return r; |
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131 | } |
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132 | |
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133 | #undef M |
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134 | #undef A |
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135 | #undef AI |
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136 | #undef C |
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137 | #undef D |
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138 | |
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139 | #endif // __cforall |
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