wyhash and wyrand are the ideal 64-bit hash function and PRNG respectively: solid, portable, fastest, simplest. wyhash passed SMHasher, wyrand passed BigCrush, practrand and designed to drop-in replace C rand(). See our manuscript.
Dear user and developers, based on recent discussions with @leo-yuriev on issue 15, I decide to upgrade wyhash to version 2 draft. Version 2 provide better security against intended attacks without obvious compromise of speed.
My deep worry on this upgrade is the split of wyhash ecosystem since many language binding have been developed. However, my goal is to build an ultimate hash function for human. Come on with me, we are young!
wyrand code:
inline uint64_t wyrand(uint64_t *seed){
*seed+=0xa0761d6478bd642full;
__uint128_t t=(__uint128_t)(*seed^0xe7037ed1a0b428dbull)*(*seed);
return (t>>64)^t;
}The speed benchmarks are as follow:
https://github.com/rurban/smhasher
| key/cycles | wyhash | XXH3 | t1ha2_atonce | t1ha1_64le | t1ha0_aes_noavx | speedup |
|---|---|---|---|---|---|---|
| 1-byte | 16.00 | 19.00 | 29.00 | 30.64 | 29.28 | 18.75% |
| 2-byte | 16.00 | 19.00 | 29.00 | 30.67 | 29.00 | 18.75% |
| 3-byte | 17.00 | 19.00 | 29.00 | 30.65 | 29.00 | 11.76% |
| 4-byte | 16.00 | 17.00 | 29.00 | 30.65 | 29.41 | 6.25% |
| 5-byte | 17.00 | 24.00 | 29.00 | 30.69 | 29.33 | 41.18% |
| 6-byte | 17.00 | 24.00 | 29.00 | 30.71 | 29.28 | 41.18% |
| 7-byte | 18.00 | 24.00 | 29.00 | 30.65 | 29.33 | 33.33% |
| 8-byte | 17.00 | 17.00 | 29.00 | 30.32 | 29.00 | 0.00% |
| 9-byte | 17.00 | 25.00 | 32.00 | 30.00 | 32.00 | 47.06% |
| 10-byte | 17.00 | 25.00 | 32.58 | 30.55 | 32.26 | 47.06% |
| 11-byte | 17.00 | 25.00 | 32.52 | 30.00 | 32.00 | 47.06% |
| 12-byte | 17.00 | 25.00 | 32.40 | 26.99 | 32.70 | 47.06% |
| 13-byte | 17.00 | 25.00 | 32.59 | 26.99 | 32.79 | 47.06% |
| 14-byte | 17.15 | 25.00 | 32.53 | 26.99 | 32.70 | 45.77% |
| 15-byte | 17.00 | 25.00 | 32.41 | 26.99 | 32.73 | 47.06% |
| 16-byte | 17.00 | 25.00 | 32.00 | 26.66 | 32.27 | 47.06% |
| 17-byte | 18.00 | 28.00 | 36.80 | 34.00 | 36.00 | 55.56% |
| 18-byte | 18.00 | 28.00 | 36.78 | 34.00 | 36.00 | 55.56% |
| 19-byte | 18.00 | 28.00 | 36.98 | 34.00 | 36.58 | 55.56% |
| 20-byte | 18.00 | 27.00 | 37.03 | 34.00 | 37.25 | 50.00% |
| 21-byte | 18.00 | 27.31 | 37.07 | 34.11 | 37.21 | 51.72% |
| 22-byte | 18.00 | 27.60 | 36.93 | 34.00 | 36.63 | 53.33% |
| 23-byte | 18.00 | 27.51 | 36.71 | 34.00 | 36.00 | 52.83% |
| 24-byte | 18.00 | 27.00 | 36.34 | 34.00 | 36.00 | 50.00% |
| 25-byte | 18.00 | 27.62 | 40.77 | 27.11 | 40.97 | 50.61% |
| 26-byte | 18.00 | 27.79 | 40.51 | 27.00 | 40.97 | 50.00% |
| 27-byte | 18.00 | 27.78 | 40.54 | 27.00 | 40.99 | 50.00% |
| 28-byte | 18.00 | 27.58 | 40.00 | 27.00 | 40.98 | 50.00% |
| 29-byte | 18.00 | 27.57 | 40.72 | 27.00 | 40.87 | 50.00% |
| 30-byte | 18.00 | 27.66 | 40.56 | 27.00 | 40.96 | 50.00% |
| 31-byte | 18.00 | 27.69 | 40.61 | 27.00 | 40.87 | 50.00% |
https://github.com/lemire/testingRNG
| PRNG | cycles per byte |
|---|---|
| xorshift_k4 | 1.60 |
| xorshift_k5 | 1.77 |
| mersennetwister | 2.41 |
| mitchellmoore | 3.12 |
| widynski | 1.88 |
| xorshift32 | 2.07 |
| pcg32 | 1.72 |
| rand | 5.04 |
| aesdragontamer | 0.71 |
| aesctr | 0.83 |
| lehmer64 | 0.86 |
| xorshift128plus | 0.85 |
| xoroshiro128plus | 0.96 |
| splitmix64 | 0.85 |
| pcg64 | 1.16 |
| xorshift1024star | 1.28 |
| xorshift1024plus | 0.91 |
| wyrand | 0.67 |
Lemire:The fastest conventional random number generator that can pass Big Crush?
| PRNG | ns/rand | vs wyrand |
|---|---|---|
| wyrand | 0.792 | 100.000% |
| lehmer64 | 1.219 | 153.858% |
| 3-lehmer64 | 0.816 | 103.010% |
| splitmix64 | 1.220 | 154.059% |
| 3-splitmix64 | 1.134 | 143.214% |
| xoshiro256 | 3.069 | 387.460% |
| pcg64 | 2.559 | 323.004% |
| pcg32 | 1.320 | 166.617% |
I thank these names:
Reini Urban
Dietrich Epp
Joshua Haberman
Tommy Ettinger
Daniel Lemire
Otmar Ertl
cocowalla
leo-yuriev
Diego Barrios Romero
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