diff options
Diffstat (limited to 'rand/rand_pcg')
| -rw-r--r-- | rand/rand_pcg/CHANGELOG.md | 11 | ||||
| -rw-r--r-- | rand/rand_pcg/Cargo.toml | 23 | ||||
| -rw-r--r-- | rand/rand_pcg/README.md | 16 | ||||
| -rw-r--r-- | rand/rand_pcg/build.rs | 7 | ||||
| -rw-r--r-- | rand/rand_pcg/src/lib.rs | 21 | ||||
| -rw-r--r-- | rand/rand_pcg/src/pcg128.rs | 177 | ||||
| -rw-r--r-- | rand/rand_pcg/src/pcg64.rs | 26 | ||||
| -rw-r--r-- | rand/rand_pcg/tests/lcg128xsl64.rs | 55 | ||||
| -rw-r--r-- | rand/rand_pcg/tests/lcg64xsh32.rs | 4 | ||||
| -rw-r--r-- | rand/rand_pcg/tests/mcg128xsl64.rs | 5 |
10 files changed, 233 insertions, 112 deletions
diff --git a/rand/rand_pcg/CHANGELOG.md b/rand/rand_pcg/CHANGELOG.md index 6f793cf..a9b82fd 100644 --- a/rand/rand_pcg/CHANGELOG.md +++ b/rand/rand_pcg/CHANGELOG.md @@ -4,9 +4,14 @@ All notable changes to this project will be documented in this file. The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). -## [0.1.2] - unreleased -- potential blocker: https://github.com/TyOverby/bincode/issues/250 -- make `bincode` a dev-dependency again +## [0.2.0] - 2019-06-12 +- Add `Lcg128Xsl64` aka `Pcg64` +- Bump minor crate version since rand_core bump is a breaking change +- Switch to Edition 2018 + +## [0.1.2] - 2019-02-23 +- require `bincode` 1.1.2 for i128 auto-detection +- make `bincode` a dev-dependency again #663 - clean up tests and Serde support ## [0.1.1] - 2018-10-04 diff --git a/rand/rand_pcg/Cargo.toml b/rand/rand_pcg/Cargo.toml index c2fcb7d..e2aa157 100644 --- a/rand/rand_pcg/Cargo.toml +++ b/rand/rand_pcg/Cargo.toml @@ -1,37 +1,32 @@ [package] name = "rand_pcg" -version = "0.1.1" +version = "0.2.0" authors = ["The Rand Project Developers"] -license = "MIT/Apache-2.0" +license = "MIT OR Apache-2.0" readme = "README.md" repository = "https://github.com/rust-random/rand" -documentation = "https://rust-random.github.io/rand/rand_pcg" +documentation = "https://rust-random.github.io/rand/rand_pcg/" homepage = "https://crates.io/crates/rand_pcg" description = """ Selected PCG random number generators """ keywords = ["random", "rng", "pcg"] categories = ["algorithms", "no-std"] -build = "build.rs" +edition = "2018" [badges] travis-ci = { repository = "rust-random/rand" } appveyor = { repository = "rust-random/rand" } [features] -serde1 = ["serde", "serde_derive"] +serde1 = ["serde"] [dependencies] -rand_core = { path = "../rand_core", version = "0.3", default-features=false } -serde = { version = "1", optional = true } -serde_derive = { version = "^1.0.38", optional = true } +rand_core = { path = "../rand_core", version = "0.5" } +serde = { version = "1", features = ["derive"], optional = true } [dev-dependencies] # This is for testing serde, unfortunately we can't specify feature-gated dev # deps yet, see: https://github.com/rust-lang/cargo/issues/1596 -# TODO: we shouldn't have to depend on i128 directly; it breaks tests on old -# compilers. `bincode` should automatically support this. -bincode = { version = "1", features = ["i128"] } - -[build-dependencies] -autocfg = "0.1" +# We require at least 1.1.2 for i128 auto-detection +bincode = { version = "1.1.2" } diff --git a/rand/rand_pcg/README.md b/rand/rand_pcg/README.md index 4599813..fe47f2d 100644 --- a/rand/rand_pcg/README.md +++ b/rand/rand_pcg/README.md @@ -6,7 +6,7 @@ [[](https://rust-random.github.io/book/) [](https://rust-random.github.io/rand/rand_pcg) [](https://docs.rs/rand_pcg) -[](https://github.com/rust-random/rand#rust-version-requirements) +[](https://github.com/rust-random/rand#rust-version-requirements) Implements a selection of PCG random number generators. @@ -24,23 +24,15 @@ Links: - [API documentation (master)](https://rust-random.github.io/rand/rand_pcg) - [API documentation (docs.rs)](https://docs.rs/rand_pcg) -- [Changelog](CHANGELOG.md) +- [Changelog](https://github.com/rust-random/rand/blob/master/rand_pcg/CHANGELOG.md) ## Crate Features -`rand_pcg` is `no_std` compatible. It does not require any functionality -outside of the `core` lib, thus there are no features to configure. +`rand_pcg` is `no_std` compatible by default. The `serde1` feature includes implementations of `Serialize` and `Deserialize` -for the included RNGs. NOTE: to use binary serialisation with any of the 64-bit -output (128-bit internal) RNGs, you must add the following dependency, since the -`i128` feature is not current enabled by default (this should be fixed soon): - -``` -bincode = { version = "1", features = ["i128"] } -``` - +for the included RNGs. ## License diff --git a/rand/rand_pcg/build.rs b/rand/rand_pcg/build.rs deleted file mode 100644 index 06e12a4..0000000 --- a/rand/rand_pcg/build.rs +++ /dev/null @@ -1,7 +0,0 @@ -extern crate autocfg; - -fn main() { - println!("cargo:rerun-if-changed=build.rs"); - let ac = autocfg::new(); - ac.emit_rustc_version(1, 26); -} diff --git a/rand/rand_pcg/src/lib.rs b/rand/rand_pcg/src/lib.rs index 9648e85..22ba4a0 100644 --- a/rand/rand_pcg/src/lib.rs +++ b/rand/rand_pcg/src/lib.rs @@ -17,11 +17,12 @@ //! - `Pcg32` aka `Lcg64Xsh32`, officially known as `pcg32`, a general //! purpose RNG. This is a good choice on both 32-bit and 64-bit CPUs //! (for 32-bit output). -//! - `Pcg64Mcg` aka `Mcg128Xsl64`, officially known as `mcg_xsl_rr_128_64`, +//! - `Pcg64` aka `Lcg128Xsl64`, officially known as `pcg64`, a general +//! purpose RNG. This is a good choice on 64-bit CPUs. +//! - `Pcg64Mcg` aka `Mcg128Xsl64`, officially known as `pcg64_fast`, //! a general purpose RNG using 128-bit multiplications. This has poor //! performance on 32-bit CPUs but is a good choice on 64-bit CPUs for -//! both 32-bit and 64-bit output. (Note: this RNG is only available using -//! Rust 1.26 or later.) +//! both 32-bit and 64-bit output. //! //! Both of these use 16 bytes of state and 128-bit seeds, and are considered //! value-stable (i.e. any change affecting the output given a fixed seed would @@ -34,15 +35,15 @@ #![deny(missing_docs)] #![deny(missing_debug_implementations)] -#![no_std] - -pub extern crate rand_core; +#![allow(clippy::unreadable_literal)] -#[cfg(feature="serde1")] extern crate serde; -#[cfg(feature="serde1")] #[macro_use] extern crate serde_derive; +#![no_std] mod pcg64; -#[cfg(all(rustc_1_26, not(target_os = "emscripten")))] mod pcg128; +#[cfg(not(target_os = "emscripten"))] mod pcg128; pub use self::pcg64::{Pcg32, Lcg64Xsh32}; -#[cfg(all(rustc_1_26, not(target_os = "emscripten")))] pub use self::pcg128::{Pcg64Mcg, Mcg128Xsl64}; +#[cfg(not(target_os = "emscripten"))] pub use self::pcg128::{ + Pcg64, Lcg128Xsl64, + Pcg64Mcg, Mcg128Xsl64, +}; diff --git a/rand/rand_pcg/src/pcg128.rs b/rand/rand_pcg/src/pcg128.rs index 9aff506..311a41b 100644 --- a/rand/rand_pcg/src/pcg128.rs +++ b/rand/rand_pcg/src/pcg128.rs @@ -14,8 +14,109 @@ const MULTIPLIER: u128 = 0x2360_ED05_1FC6_5DA4_4385_DF64_9FCC_F645; use core::fmt; -use core::mem::transmute; use rand_core::{RngCore, SeedableRng, Error, le}; +#[cfg(feature="serde1")] use serde::{Serialize, Deserialize}; + +/// A PCG random number generator (XSL RR 128/64 (LCG) variant). +/// +/// Permuted Congruential Generator with 128-bit state, internal Linear +/// Congruential Generator, and 64-bit output via "xorshift low (bits), +/// random rotation" output function. +/// +/// This is a 128-bit LCG with explicitly chosen stream with the PCG-XSL-RR +/// output function. This combination is the standard `pcg64`. +/// +/// Despite the name, this implementation uses 32 bytes (256 bit) space +/// comprising 128 bits of state and 128 bits stream selector. These are both +/// set by `SeedableRng`, using a 256-bit seed. +#[derive(Clone)] +#[cfg_attr(feature="serde1", derive(Serialize,Deserialize))] +pub struct Lcg128Xsl64 { + state: u128, + increment: u128, +} + +/// `Lcg128Xsl64` is also officially known as `pcg64`. +pub type Pcg64 = Lcg128Xsl64; + +impl Lcg128Xsl64 { + /// Construct an instance compatible with PCG seed and stream. + /// + /// Note that PCG specifies default values for both parameters: + /// + /// - `state = 0xcafef00dd15ea5e5` + /// - `stream = 0xa02bdbf7bb3c0a7ac28fa16a64abf96` + pub fn new(state: u128, stream: u128) -> Self { + // The increment must be odd, hence we discard one bit: + let increment = (stream << 1) | 1; + Lcg128Xsl64::from_state_incr(state, increment) + } + + #[inline] + fn from_state_incr(state: u128, increment: u128) -> Self { + let mut pcg = Lcg128Xsl64 { state, increment }; + // Move away from inital value: + pcg.state = pcg.state.wrapping_add(pcg.increment); + pcg.step(); + pcg + } + + #[inline] + fn step(&mut self) { + // prepare the LCG for the next round + self.state = self.state + .wrapping_mul(MULTIPLIER) + .wrapping_add(self.increment); + } +} + +// Custom Debug implementation that does not expose the internal state +impl fmt::Debug for Lcg128Xsl64 { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!(f, "Lcg128Xsl64 {{}}") + } +} + +/// We use a single 255-bit seed to initialise the state and select a stream. +/// One `seed` bit (lowest bit of `seed[8]`) is ignored. +impl SeedableRng for Lcg128Xsl64 { + type Seed = [u8; 32]; + + fn from_seed(seed: Self::Seed) -> Self { + let mut seed_u64 = [0u64; 4]; + le::read_u64_into(&seed, &mut seed_u64); + let state = u128::from(seed_u64[0]) | (u128::from(seed_u64[1]) << 64); + let incr = u128::from(seed_u64[2]) | (u128::from(seed_u64[3]) << 64); + + // The increment must be odd, hence we discard one bit: + Lcg128Xsl64::from_state_incr(state, incr | 1) + } +} + +impl RngCore for Lcg128Xsl64 { + #[inline] + fn next_u32(&mut self) -> u32 { + self.next_u64() as u32 + } + + #[inline] + fn next_u64(&mut self) -> u64 { + self.step(); + output_xsl_rr(self.state) + } + + #[inline] + fn fill_bytes(&mut self, dest: &mut [u8]) { + fill_bytes_impl(self, dest) + } + + #[inline] + fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { + self.fill_bytes(dest); + Ok(()) + } +} + /// A PCG random number generator (XSL 128/64 (MCG) variant). /// @@ -23,19 +124,18 @@ use rand_core::{RngCore, SeedableRng, Error, le}; /// Congruential Generator, and 64-bit output via "xorshift low (bits), /// random rotation" output function. /// -/// This is a 128-bit MCG with the PCG-XSL-RR output function. +/// This is a 128-bit MCG with the PCG-XSL-RR output function, also known as +/// `pcg64_fast`. /// Note that compared to the standard `pcg64` (128-bit LCG with PCG-XSL-RR /// output function), this RNG is faster, also has a long cycle, and still has /// good performance on statistical tests. -/// -/// Note: this RNG is only available using Rust 1.26 or later. #[derive(Clone)] #[cfg_attr(feature="serde1", derive(Serialize,Deserialize))] pub struct Mcg128Xsl64 { state: u128, } -/// A friendly name for `Mcg128Xsl64`. +/// A friendly name for `Mcg128Xsl64` (also known as `pcg64_fast`). pub type Pcg64Mcg = Mcg128Xsl64; impl Mcg128Xsl64 { @@ -66,8 +166,8 @@ impl SeedableRng for Mcg128Xsl64 { // Read as if a little-endian u128 value: let mut seed_u64 = [0u64; 2]; le::read_u64_into(&seed, &mut seed_u64); - let state = (seed_u64[0] as u128) | - (seed_u64[1] as u128) << 64; + let state = u128::from(seed_u64[0]) | + u128::from(seed_u64[1]) << 64; Mcg128Xsl64::new(state) } } @@ -80,43 +180,46 @@ impl RngCore for Mcg128Xsl64 { #[inline] fn next_u64(&mut self) -> u64 { - // prepare the LCG for the next round - let state = self.state.wrapping_mul(MULTIPLIER); - self.state = state; - - // Output function XSL RR ("xorshift low (bits), random rotation") - // Constants are for 128-bit state, 64-bit output - const XSHIFT: u32 = 64; // (128 - 64 + 64) / 2 - const ROTATE: u32 = 122; // 128 - 6 - - let rot = (state >> ROTATE) as u32; - let xsl = ((state >> XSHIFT) as u64) ^ (state as u64); - xsl.rotate_right(rot) + self.state = self.state.wrapping_mul(MULTIPLIER); + output_xsl_rr(self.state) } #[inline] fn fill_bytes(&mut self, dest: &mut [u8]) { - // specialisation of impls::fill_bytes_via_next; approx 3x faster - let mut left = dest; - while left.len() >= 8 { - let (l, r) = {left}.split_at_mut(8); - left = r; - let chunk: [u8; 8] = unsafe { - transmute(self.next_u64().to_le()) - }; - l.copy_from_slice(&chunk); - } - let n = left.len(); - if n > 0 { - let chunk: [u8; 8] = unsafe { - transmute(self.next_u64().to_le()) - }; - left.copy_from_slice(&chunk[..n]); - } + fill_bytes_impl(self, dest) } #[inline] fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { - Ok(self.fill_bytes(dest)) + self.fill_bytes(dest); + Ok(()) + } +} + +#[inline(always)] +fn output_xsl_rr(state: u128) -> u64 { + // Output function XSL RR ("xorshift low (bits), random rotation") + // Constants are for 128-bit state, 64-bit output + const XSHIFT: u32 = 64; // (128 - 64 + 64) / 2 + const ROTATE: u32 = 122; // 128 - 6 + + let rot = (state >> ROTATE) as u32; + let xsl = ((state >> XSHIFT) as u64) ^ (state as u64); + xsl.rotate_right(rot) +} + +#[inline(always)] +fn fill_bytes_impl<R: RngCore + ?Sized>(rng: &mut R, dest: &mut [u8]) { + let mut left = dest; + while left.len() >= 8 { + let (l, r) = {left}.split_at_mut(8); + left = r; + let chunk: [u8; 8] = rng.next_u64().to_le_bytes(); + l.copy_from_slice(&chunk); + } + let n = left.len(); + if n > 0 { + let chunk: [u8; 8] = rng.next_u64().to_le_bytes(); + left.copy_from_slice(&chunk[..n]); } } diff --git a/rand/rand_pcg/src/pcg64.rs b/rand/rand_pcg/src/pcg64.rs index 9177ec2..fadc6dc 100644 --- a/rand/rand_pcg/src/pcg64.rs +++ b/rand/rand_pcg/src/pcg64.rs @@ -11,8 +11,8 @@ //! PCG random number generators use core::fmt; -use core::mem::transmute; use rand_core::{RngCore, SeedableRng, Error, le, impls}; +#[cfg(feature="serde1")] use serde::{Serialize, Deserialize}; // This is the default multiplier used by PCG for 64-bit state. const MULTIPLIER: u64 = 6364136223846793005; @@ -45,7 +45,8 @@ impl Lcg64Xsh32 { /// Note that PCG specifies default values for both parameters: /// /// - `state = 0xcafef00dd15ea5e5` - /// - `stream = 721347520444481703` + /// - `stream = 0xa02bdbf7bb3c0a7` + // Note: stream is 1442695040888963407u64 >> 1 pub fn new(state: u64, stream: u64) -> Self { // The increment must be odd, hence we discard one bit: let increment = (stream << 1) | 1; @@ -115,27 +116,12 @@ impl RngCore for Lcg64Xsh32 { #[inline] fn fill_bytes(&mut self, dest: &mut [u8]) { - // specialisation of impls::fill_bytes_via_next; approx 40% faster - let mut left = dest; - while left.len() >= 4 { - let (l, r) = {left}.split_at_mut(4); - left = r; - let chunk: [u8; 4] = unsafe { - transmute(self.next_u32().to_le()) - }; - l.copy_from_slice(&chunk); - } - let n = left.len(); - if n > 0 { - let chunk: [u8; 4] = unsafe { - transmute(self.next_u32().to_le()) - }; - left.copy_from_slice(&chunk[..n]); - } + impls::fill_bytes_via_next(self, dest) } #[inline] fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { - Ok(self.fill_bytes(dest)) + self.fill_bytes(dest); + Ok(()) } } diff --git a/rand/rand_pcg/tests/lcg128xsl64.rs b/rand/rand_pcg/tests/lcg128xsl64.rs new file mode 100644 index 0000000..efc72ff --- /dev/null +++ b/rand/rand_pcg/tests/lcg128xsl64.rs @@ -0,0 +1,55 @@ +use rand_core::{RngCore, SeedableRng}; +use rand_pcg::{Lcg128Xsl64, Pcg64}; + +#[test] +fn test_lcg128xsl64_construction() { + // Test that various construction techniques produce a working RNG. + let seed = [1,2,3,4, 5,6,7,8, 9,10,11,12, 13,14,15,16, + 17,18,19,20, 21,22,23,24, 25,26,27,28, 29,30,31,32]; + let mut rng1 = Lcg128Xsl64::from_seed(seed); + assert_eq!(rng1.next_u64(), 8740028313290271629); + + let mut rng2 = Lcg128Xsl64::from_rng(&mut rng1).unwrap(); + assert_eq!(rng2.next_u64(), 1922280315005786345); + + let mut rng3 = Lcg128Xsl64::seed_from_u64(0); + assert_eq!(rng3.next_u64(), 2354861276966075475); + + // This is the same as Lcg128Xsl64, so we only have a single test: + let mut rng4 = Pcg64::seed_from_u64(0); + assert_eq!(rng4.next_u64(), 2354861276966075475); +} + +#[test] +fn test_lcg128xsl64_true_values() { + // Numbers copied from official test suite (C version). + let mut rng = Lcg128Xsl64::new(42, 54); + + let mut results = [0u64; 6]; + for i in results.iter_mut() { *i = rng.next_u64(); } + let expected: [u64; 6] = [0x86b1da1d72062b68, 0x1304aa46c9853d39, + 0xa3670e9e0dd50358, 0xf9090e529a7dae00, 0xc85b9fd837996f2c, 0x606121f8e3919196]; + assert_eq!(results, expected); +} + +#[cfg(feature="serde1")] +#[test] +fn test_lcg128xsl64_serde() { + use bincode; + use std::io::{BufWriter, BufReader}; + + let mut rng = Lcg128Xsl64::seed_from_u64(0); + + let buf: Vec<u8> = Vec::new(); + let mut buf = BufWriter::new(buf); + bincode::serialize_into(&mut buf, &rng).expect("Could not serialize"); + + let buf = buf.into_inner().unwrap(); + let mut read = BufReader::new(&buf[..]); + let mut deserialized: Lcg128Xsl64 = bincode::deserialize_from(&mut read) + .expect("Could not deserialize"); + + for _ in 0..16 { + assert_eq!(rng.next_u64(), deserialized.next_u64()); + } +} diff --git a/rand/rand_pcg/tests/lcg64xsh32.rs b/rand/rand_pcg/tests/lcg64xsh32.rs index 775b12c..e05bcc1 100644 --- a/rand/rand_pcg/tests/lcg64xsh32.rs +++ b/rand/rand_pcg/tests/lcg64xsh32.rs @@ -1,7 +1,3 @@ -extern crate rand_pcg; -extern crate rand_core; -#[cfg(all(feature="serde1", test))] extern crate bincode; - use rand_core::{RngCore, SeedableRng}; use rand_pcg::{Lcg64Xsh32, Pcg32}; diff --git a/rand/rand_pcg/tests/mcg128xsl64.rs b/rand/rand_pcg/tests/mcg128xsl64.rs index 3279536..d58fa75 100644 --- a/rand/rand_pcg/tests/mcg128xsl64.rs +++ b/rand/rand_pcg/tests/mcg128xsl64.rs @@ -1,8 +1,3 @@ -#![cfg(rustc_1_26)] -extern crate rand_pcg; -extern crate rand_core; -#[cfg(all(feature="serde1", test))] extern crate bincode; - use rand_core::{RngCore, SeedableRng}; use rand_pcg::{Mcg128Xsl64, Pcg64Mcg}; |