1 /* Written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
3 To the extent possible under law, the author has dedicated all copyright
4 and related and neighboring rights to this software to the public domain
5 worldwide. This software is distributed without any warranty.
7 See <http://creativecommons.org/publicdomain/zero/1.0/>. */
11 /* This is xoshiro256** 1.0, one of our all-purpose, rock-solid
12 generators. It has excellent (sub-ns) speed, a state (256 bits) that is
13 large enough for any parallel application, and it passes all tests we
16 For generating just floating-point numbers, xoshiro256+ is even faster.
18 The state must be seeded so that it is not everywhere zero. If you have
19 a 64-bit seed, we suggest to seed a splitmix64 generator and use its
22 static inline uint64_t rotl(const uint64_t x, int k) {
23 return (x << k) | (x >> (64 - k));
30 const uint64_t result = rotl(s[1] * 5, 7) * 9;
32 const uint64_t t = s[1] << 17;
41 s[3] = rotl(s[3], 45);
47 /* This is the jump function for the generator. It is equivalent
48 to 2^128 calls to next(); it can be used to generate 2^128
49 non-overlapping subsequences for parallel computations. */
52 static const uint64_t JUMP[] = { 0x180ec6d33cfd0aba, 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c };
58 for(int i = 0; i < sizeof JUMP / sizeof *JUMP; i++)
59 for(int b = 0; b < 64; b++) {
60 if (JUMP[i] & UINT64_C(1) << b) {
77 /* This is the long-jump function for the generator. It is equivalent to
78 2^192 calls to next(); it can be used to generate 2^64 starting points,
79 from each of which jump() will generate 2^64 non-overlapping
80 subsequences for parallel distributed computations. */
82 void long_jump(void) {
83 static const uint64_t LONG_JUMP[] = { 0x76e15d3efefdcbbf, 0xc5004e441c522fb3, 0x77710069854ee241, 0x39109bb02acbe635 };
89 for(int i = 0; i < sizeof LONG_JUMP / sizeof *LONG_JUMP; i++)
90 for(int b = 0; b < 64; b++) {
91 if (LONG_JUMP[i] & UINT64_C(1) << b) {