diff options
Diffstat (limited to 'libgfortran/intrinsics/random.c')
-rw-r--r-- | libgfortran/intrinsics/random.c | 213 |
1 files changed, 99 insertions, 114 deletions
diff --git a/libgfortran/intrinsics/random.c b/libgfortran/intrinsics/random.c index 7476439647c..cad21fedb57 100644 --- a/libgfortran/intrinsics/random.c +++ b/libgfortran/intrinsics/random.c @@ -164,7 +164,7 @@ rnumber_16 (GFC_REAL_16 *f, GFC_UINTEGER_8 v1, GFC_UINTEGER_8 v2) /* - We use the xorshift1024* generator, a fast high-quality generator + We use the xoshiro256** generator, a fast high-quality generator that: - passes TestU1 without any failures @@ -172,15 +172,15 @@ rnumber_16 (GFC_REAL_16 *f, GFC_UINTEGER_8 v1, GFC_UINTEGER_8 v2) - provides a "jump" function making it easy to provide many independent parallel streams. - - Long period of 2**1024 - 1 + - Long period of 2**256 - 1 A description can be found at - http://vigna.di.unimi.it/ftp/papers/xorshift.pdf + http://prng.di.unimi.it/ or - http://arxiv.org/abs/1402.6246 + https://arxiv.org/abs/1805.01407 The paper includes public domain source code which is the basis for the implementation below. @@ -189,10 +189,9 @@ rnumber_16 (GFC_REAL_16 *f, GFC_UINTEGER_8 v1, GFC_UINTEGER_8 v2) typedef struct { bool init; - int p; - uint64_t s[16]; + uint64_t s[4]; } -xorshift1024star_state; +prng_state; /* master_init, njumps, and master_state are the only variables @@ -201,28 +200,24 @@ static bool master_init; static unsigned njumps; /* How many times we have jumped. */ static uint64_t master_state[] = { 0xad63fa1ed3b55f36ULL, 0xd94473e78978b497ULL, 0xbc60592a98172477ULL, - 0xa3de7c6e81265301ULL, 0x586640c5e785af27ULL, 0x7a2a3f63b67ce5eaULL, - 0x9fde969f922d9b82ULL, 0xe6fe34379b3f3822ULL, 0x6c277eac3e99b6c2ULL, - 0x9197290ab0d3f069ULL, 0xdb227302f6c25576ULL, 0xee0209aee527fae9ULL, - 0x675666a793cd05b9ULL, 0xd048c99fbc70c20fULL, 0x775f8c3dba385ef5ULL, - 0x625288bc262faf33ULL + 0xa3de7c6e81265301ULL }; static __gthread_key_t rand_state_key; -static xorshift1024star_state* +static prng_state* get_rand_state (void) { /* For single threaded apps. */ - static xorshift1024star_state rand_state; + static prng_state rand_state; if (__gthread_active_p ()) { void* p = __gthread_getspecific (rand_state_key); if (!p) { - p = xcalloc (1, sizeof (xorshift1024star_state)); + p = xcalloc (1, sizeof (prng_state)); __gthread_setspecific (rand_state_key, p); } return p; @@ -231,76 +226,79 @@ get_rand_state (void) return &rand_state; } +static inline uint64_t +rotl (const uint64_t x, int k) +{ + return (x << k) | (x >> (64 - k)); +} + static uint64_t -xorshift1024star (xorshift1024star_state* rs) +prng_next (prng_state* rs) { - int p = rs->p; - const uint64_t s0 = rs->s[p]; - uint64_t s1 = rs->s[p = (p + 1) & 15]; - s1 ^= s1 << 31; - rs->s[p] = s1 ^ s0 ^ (s1 >> 11) ^ (s0 >> 30); - rs->p = p; - return rs->s[p] * UINT64_C(1181783497276652981); + const uint64_t result = rotl(rs->s[1] * 5, 7) * 9; + + const uint64_t t = rs->s[1] << 17; + + rs->s[2] ^= rs->s[0]; + rs->s[3] ^= rs->s[1]; + rs->s[1] ^= rs->s[2]; + rs->s[0] ^= rs->s[3]; + + rs->s[2] ^= t; + + rs->s[3] = rotl(rs->s[3], 45); + + return result; } /* This is the jump function for the generator. It is equivalent to - 2^512 calls to xorshift1024star(); it can be used to generate 2^512 + 2^128 calls to prng_next(); it can be used to generate 2^128 non-overlapping subsequences for parallel computations. */ static void -jump (xorshift1024star_state* rs) +jump (prng_state* rs) { - static const uint64_t JUMP[] = { - 0x84242f96eca9c41dULL, 0xa3c65b8776f96855ULL, 0x5b34a39f070b5837ULL, - 0x4489affce4f31a1eULL, 0x2ffeeb0a48316f40ULL, 0xdc2d9891fe68c022ULL, - 0x3659132bb12fea70ULL, 0xaac17d8efa43cab8ULL, 0xc4cb815590989b13ULL, - 0x5ee975283d71c93bULL, 0x691548c86c1bd540ULL, 0x7910c41d10a1e6a5ULL, - 0x0b5fc64563b3e2a8ULL, 0x047f7684e9fc949dULL, 0xb99181f2d8f685caULL, - 0x284600e3f30e38c3ULL - }; - - uint64_t t[16] = { 0 }; + static const uint64_t JUMP[] = { 0x180ec6d33cfd0aba, 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c }; + + uint64_t s0 = 0; + uint64_t s1 = 0; + uint64_t s2 = 0; + uint64_t s3 = 0; for(size_t i = 0; i < sizeof JUMP / sizeof *JUMP; i++) - for(int b = 0; b < 64; b++) - { - if (JUMP[i] & 1ULL << b) - for(int j = 0; j < 16; j++) - t[j] ^= rs->s[(j + rs->p) & 15]; - xorshift1024star (rs); + for(int b = 0; b < 64; b++) { + if (JUMP[i] & UINT64_C(1) << b) { + s0 ^= rs->s[0]; + s1 ^= rs->s[1]; + s2 ^= rs->s[2]; + s3 ^= rs->s[3]; } - for(int j = 0; j < 16; j++) - rs->s[(j + rs->p) & 15] = t[j]; -} + prng_next (rs); + } + rs->s[0] = s0; + rs->s[1] = s1; + rs->s[2] = s2; + rs->s[3] = s3; +} -/* Super-simple LCG generator used in getosrandom () if /dev/urandom - doesn't exist. */ -#define M 2147483647 /* 2^31 - 1 (A large prime number) */ -#define A 16807 /* Prime root of M, passes statistical tests and produces a full cycle */ -#define Q 127773 /* M / A (To avoid overflow on A * seed) */ -#define R 2836 /* M % A (To avoid overflow on A * seed) */ +/* Splitmix64 recommended by xoshiro author for initializing. After + getting one uint64_t value from the OS, this is used to fill in the + rest of the xoshiro state. */ -__attribute__((unused)) static uint32_t -lcg_parkmiller(uint32_t seed) +static uint64_t +splitmix64 (uint64_t x) { - uint32_t hi = seed / Q; - uint32_t lo = seed % Q; - int32_t test = A * lo - R * hi; - if (test <= 0) - test += M; - return test; + uint64_t z = (x += 0x9e3779b97f4a7c15); + z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9; + z = (z ^ (z >> 27)) * 0x94d049bb133111eb; + return z ^ (z >> 31); } -#undef M -#undef A -#undef Q -#undef R - -/* Get some random bytes from the operating system in order to seed +/* Get some bytes from the operating system in order to seed the PRNG. */ static int @@ -315,7 +313,7 @@ getosrandom (void *buf, size_t buflen) #else #ifdef HAVE_GETENTROPY if (getentropy (buf, buflen) == 0) - return 0; + return buflen; #endif int flags = O_RDONLY; #ifdef O_CLOEXEC @@ -328,7 +326,7 @@ getosrandom (void *buf, size_t buflen) close (fd); return res; } - uint32_t seed = 1234567890; + uint64_t seed = 0x047f7684e9fc949dULL; time_t secs; long usecs; if (gf_gettime (&secs, &usecs) == 0) @@ -340,13 +338,9 @@ getosrandom (void *buf, size_t buflen) pid_t pid = getpid(); seed ^= pid; #endif - uint32_t* ub = buf; - for (size_t i = 0; i < buflen / sizeof (uint32_t); i++) - { - ub[i] = seed; - seed = lcg_parkmiller (seed); - } - return buflen; + size_t size = buflen < sizeof (uint64_t) ? buflen : sizeof (uint64_t); + memcpy (buf, &seed, size); + return size; #endif /* __MINGW64_VERSION_MAJOR */ } @@ -355,13 +349,16 @@ getosrandom (void *buf, size_t buflen) using the master state and the number of times we must jump. */ static void -init_rand_state (xorshift1024star_state* rs, const bool locked) +init_rand_state (prng_state* rs, const bool locked) { if (!locked) __gthread_mutex_lock (&random_lock); if (!master_init) { - getosrandom (master_state, sizeof (master_state)); + uint64_t os_seed; + getosrandom (&os_seed, sizeof (os_seed)); + for (uint64_t i = 0; i < sizeof (master_state) / sizeof (uint64_t); i++) + master_state[i] = splitmix64 (os_seed); njumps = 0; master_init = true; } @@ -381,11 +378,11 @@ init_rand_state (xorshift1024star_state* rs, const bool locked) void random_r4 (GFC_REAL_4 *x) { - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); if (unlikely (!rs->init)) init_rand_state (rs, false); - uint64_t r = xorshift1024star (rs); + uint64_t r = prng_next (rs); /* Take the higher bits, ensuring that a stream of real(4), real(8), and real(10) will be identical (except for precision). */ uint32_t high = (uint32_t) (r >> 32); @@ -400,11 +397,11 @@ void random_r8 (GFC_REAL_8 *x) { GFC_UINTEGER_8 r; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); if (unlikely (!rs->init)) init_rand_state (rs, false); - r = xorshift1024star (rs); + r = prng_next (rs); rnumber_8 (x, r); } iexport(random_r8); @@ -418,11 +415,11 @@ void random_r10 (GFC_REAL_10 *x) { GFC_UINTEGER_8 r; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); if (unlikely (!rs->init)) init_rand_state (rs, false); - r = xorshift1024star (rs); + r = prng_next (rs); rnumber_10 (x, r); } iexport(random_r10); @@ -438,12 +435,12 @@ void random_r16 (GFC_REAL_16 *x) { GFC_UINTEGER_8 r1, r2; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); if (unlikely (!rs->init)) init_rand_state (rs, false); - r1 = xorshift1024star (rs); - r2 = xorshift1024star (rs); + r1 = prng_next (rs); + r2 = prng_next (rs); rnumber_16 (x, r1, r2); } iexport(random_r16); @@ -463,7 +460,7 @@ arandom_r4 (gfc_array_r4 *x) index_type stride0; index_type dim; GFC_REAL_4 *dest; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); dest = x->base_addr; @@ -486,7 +483,7 @@ arandom_r4 (gfc_array_r4 *x) while (dest) { /* random_r4 (dest); */ - uint64_t r = xorshift1024star (rs); + uint64_t r = prng_next (rs); uint32_t high = (uint32_t) (r >> 32); rnumber_4 (dest, high); @@ -530,7 +527,7 @@ arandom_r8 (gfc_array_r8 *x) index_type stride0; index_type dim; GFC_REAL_8 *dest; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); dest = x->base_addr; @@ -553,7 +550,7 @@ arandom_r8 (gfc_array_r8 *x) while (dest) { /* random_r8 (dest); */ - uint64_t r = xorshift1024star (rs); + uint64_t r = prng_next (rs); rnumber_8 (dest, r); /* Advance to the next element. */ @@ -598,7 +595,7 @@ arandom_r10 (gfc_array_r10 *x) index_type stride0; index_type dim; GFC_REAL_10 *dest; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); dest = x->base_addr; @@ -621,7 +618,7 @@ arandom_r10 (gfc_array_r10 *x) while (dest) { /* random_r10 (dest); */ - uint64_t r = xorshift1024star (rs); + uint64_t r = prng_next (rs); rnumber_10 (dest, r); /* Advance to the next element. */ @@ -668,7 +665,7 @@ arandom_r16 (gfc_array_r16 *x) index_type stride0; index_type dim; GFC_REAL_16 *dest; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); dest = x->base_addr; @@ -691,8 +688,8 @@ arandom_r16 (gfc_array_r16 *x) while (dest) { /* random_r16 (dest); */ - uint64_t r1 = xorshift1024star (rs); - uint64_t r2 = xorshift1024star (rs); + uint64_t r1 = prng_next (rs); + uint64_t r2 = prng_next (rs); rnumber_16 (dest, r1, r2); /* Advance to the next element. */ @@ -734,11 +731,7 @@ arandom_r16 (gfc_array_r16 *x) static const uint64_t xor_keys[] = { 0xbd0c5b6e50c2df49ULL, 0xd46061cd46e1df38ULL, 0xbb4f4d4ed6103544ULL, - 0x114a583d0756ad39ULL, 0x4b5ad8623d0aaab6ULL, 0x3f2ed7afbe0c0f21ULL, - 0xdec83fd65f113445ULL, 0x3824f8fbc4f10d24ULL, 0x5d9025af05878911ULL, - 0x500bc46b540340e9ULL, 0x8bd53298e0d00530ULL, 0x57886e40a952e06aULL, - 0x926e76c88e31cdb6ULL, 0xbd0724dac0a3a5f9ULL, 0xc5c8981b858ab796ULL, - 0xbb12ab2694c2b32cULL + 0x114a583d0756ad39ULL }; @@ -768,9 +761,9 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get) runtime_error ("RANDOM_SEED should have at most one argument present."); if (size != NULL) - *size = SZ + 1; + *size = SZ; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); /* Return the seed to GET data. */ if (get != NULL) @@ -780,7 +773,7 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get) runtime_error ("Array rank of GET is not 1."); /* If the array is too small, abort. */ - if (GFC_DESCRIPTOR_EXTENT(get,0) < (index_type) SZ + 1) + if (GFC_DESCRIPTOR_EXTENT(get,0) < (index_type) SZ) runtime_error ("Array size of GET is too small."); if (!rs->init) @@ -794,9 +787,6 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get) memcpy (&(get->base_addr[(SZ - 1 - i) * GFC_DESCRIPTOR_STRIDE(get,0)]), (unsigned char*) seed + i * sizeof(GFC_UINTEGER_4), sizeof(GFC_UINTEGER_4)); - - /* Finally copy the value of p after the seed. */ - get->base_addr[SZ * GFC_DESCRIPTOR_STRIDE(get, 0)] = rs->p; } else @@ -818,7 +808,7 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get) runtime_error ("Array rank of PUT is not 1."); /* If the array is too small, abort. */ - if (GFC_DESCRIPTOR_EXTENT(put,0) < (index_type) SZ + 1) + if (GFC_DESCRIPTOR_EXTENT(put,0) < (index_type) SZ) runtime_error ("Array size of PUT is too small."); /* We copy the seed given by the user. */ @@ -833,8 +823,6 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get) njumps = 0; master_init = true; init_rand_state (rs, true); - - rs->p = put->base_addr[SZ * GFC_DESCRIPTOR_STRIDE(put, 0)] & 15; } __gthread_mutex_unlock (&random_lock); @@ -855,9 +843,9 @@ random_seed_i8 (GFC_INTEGER_8 *size, gfc_array_i8 *put, gfc_array_i8 *get) #define SZ (sizeof (master_state) / sizeof (GFC_INTEGER_8)) if (size != NULL) - *size = SZ + 1; + *size = SZ; - xorshift1024star_state* rs = get_rand_state(); + prng_state* rs = get_rand_state(); /* Return the seed to GET data. */ if (get != NULL) @@ -867,7 +855,7 @@ random_seed_i8 (GFC_INTEGER_8 *size, gfc_array_i8 *put, gfc_array_i8 *get) runtime_error ("Array rank of GET is not 1."); /* If the array is too small, abort. */ - if (GFC_DESCRIPTOR_EXTENT(get,0) < (index_type) SZ + 1) + if (GFC_DESCRIPTOR_EXTENT(get,0) < (index_type) SZ) runtime_error ("Array size of GET is too small."); if (!rs->init) @@ -880,8 +868,6 @@ random_seed_i8 (GFC_INTEGER_8 *size, gfc_array_i8 *put, gfc_array_i8 *get) for (size_t i = 0; i < SZ; i++) memcpy (&(get->base_addr[i * GFC_DESCRIPTOR_STRIDE(get,0)]), &seed[i], sizeof (GFC_UINTEGER_8)); - - get->base_addr[SZ * GFC_DESCRIPTOR_STRIDE(get, 0)] = rs->p; } else @@ -903,7 +889,7 @@ random_seed_i8 (GFC_INTEGER_8 *size, gfc_array_i8 *put, gfc_array_i8 *get) runtime_error ("Array rank of PUT is not 1."); /* If the array is too small, abort. */ - if (GFC_DESCRIPTOR_EXTENT(put,0) < (index_type) SZ + 1) + if (GFC_DESCRIPTOR_EXTENT(put,0) < (index_type) SZ) runtime_error ("Array size of PUT is too small."); /* This code now should do correct strides. */ @@ -915,7 +901,6 @@ random_seed_i8 (GFC_INTEGER_8 *size, gfc_array_i8 *put, gfc_array_i8 *get) njumps = 0; master_init = true; init_rand_state (rs, true); - rs->p = put->base_addr[SZ * GFC_DESCRIPTOR_STRIDE(put, 0)] & 15; } |