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Diffstat (limited to 'rand/rand_xoshiro/src/xoshiro512plus.rs')
-rw-r--r-- | rand/rand_xoshiro/src/xoshiro512plus.rs | 122 |
1 files changed, 0 insertions, 122 deletions
diff --git a/rand/rand_xoshiro/src/xoshiro512plus.rs b/rand/rand_xoshiro/src/xoshiro512plus.rs deleted file mode 100644 index 4b589f2..0000000 --- a/rand/rand_xoshiro/src/xoshiro512plus.rs +++ /dev/null @@ -1,122 +0,0 @@ -// Copyright 2018 Developers of the Rand project. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -#[cfg(feature="serde1")] use serde::{Serialize, Deserialize}; -use rand_core::impls::fill_bytes_via_next; -use rand_core::le::read_u64_into; -use rand_core::{SeedableRng, RngCore, Error}; - -use crate::Seed512; - -/// A xoshiro512+ random number generator. -/// -/// The xoshiro512+ algorithm is not suitable for cryptographic purposes, but -/// is very fast and has good statistical properties, besides a low linear -/// complexity in the lowest bits. -/// -/// The algorithm used here is translated from [the `xoshiro512plus.c` -/// reference source code](http://xoshiro.di.unimi.it/xoshiro512plus.c) by -/// David Blackman and Sebastiano Vigna. -#[derive(Debug, Clone)] -#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))] -pub struct Xoshiro512Plus { - s: [u64; 8], -} - -impl Xoshiro512Plus { - /// Jump forward, equivalently to 2^256 calls to `next_u64()`. - /// - /// This can be used to generate 2^256 non-overlapping subsequences for - /// parallel computations. - /// - /// ``` - /// use rand_xoshiro::rand_core::SeedableRng; - /// use rand_xoshiro::Xoshiro512Plus; - /// - /// let rng1 = Xoshiro512Plus::seed_from_u64(0); - /// let mut rng2 = rng1.clone(); - /// rng2.jump(); - /// let mut rng3 = rng2.clone(); - /// rng3.jump(); - /// ``` - pub fn jump(&mut self) { - impl_jump!(u64, self, [ - 0x33ed89b6e7a353f9, 0x760083d7955323be, 0x2837f2fbb5f22fae, - 0x4b8c5674d309511c, 0xb11ac47a7ba28c25, 0xf1be7667092bcc1c, - 0x53851efdb6df0aaf, 0x1ebbc8b23eaf25db - ]); - } -} - -impl SeedableRng for Xoshiro512Plus { - type Seed = Seed512; - - /// Create a new `Xoshiro512Plus`. If `seed` is entirely 0, it will be - /// mapped to a different seed. - #[inline] - fn from_seed(seed: Seed512) -> Xoshiro512Plus { - deal_with_zero_seed!(seed, Self); - let mut state = [0; 8]; - read_u64_into(&seed.0, &mut state); - Xoshiro512Plus { s: state } - } - - /// Seed a `Xoshiro512Plus` from a `u64` using `SplitMix64`. - fn seed_from_u64(seed: u64) -> Xoshiro512Plus { - from_splitmix!(seed) - } -} - -impl RngCore for Xoshiro512Plus { - #[inline] - fn next_u32(&mut self) -> u32 { - self.next_u64() as u32 - } - - #[inline] - fn next_u64(&mut self) -> u64 { - let result_plus = self.s[0].wrapping_add(self.s[2]); - impl_xoshiro_large!(self); - result_plus - } - - #[inline] - fn fill_bytes(&mut self, dest: &mut [u8]) { - fill_bytes_via_next(self, dest); - } - - #[inline] - fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { - self.fill_bytes(dest); - Ok(()) - } -} - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn reference() { - let mut rng = Xoshiro512Plus::from_seed(Seed512( - [1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, - 3, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, - 5, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, - 7, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0])); - // These values were produced with the reference implementation: - // http://xoshiro.di.unimi.it/xoshiro512plus.c - let expected = [ - 4, 8, 4113, 25169936, 52776585412635, 57174648719367, - 9223482039571869716, 9331471677901559830, 9340533895746033672, - 14078399799840753678, - ]; - for &e in &expected { - assert_eq!(rng.next_u64(), e); - } - } -} |