--- /dev/null
+{
+ "git": {
+ "sha1": "8792268dfe57e49bb4518190bf4fe66176759a44"
+ }
+}
--- /dev/null
+# Changelog
+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).
+
+## [0.3.1] - 2021-06-15
+- Add `advance` methods to RNGs (#1111)
+- Document dependencies between streams (#1122)
+
+## [0.3.0] - 2020-12-08
+- Bump `rand_core` version to 0.6.0
+- Bump MSRV to 1.36 (#1011)
+- Derive PartialEq+Eq for Lcg64Xsh32, Lcg128Xsl64, and Mcg128Xsl64 (#979)
+
+## [0.2.1] - 2019-10-22
+- Bump `bincode` version to 1.1.4 to fix minimal-dependency builds
+- Removed unused `autocfg` build dependency.
+
+## [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
+- make `bincode` an explicit dependency when using Serde
+
+## [0.1.0] - 2018-10-04
+Initial release, including:
+
+- `Lcg64Xsh32` aka `Pcg32`
+- `Mcg128Xsl64` aka `Pcg64Mcg`
--- /dev/null
+Copyrights in the Rand project are retained by their contributors. No
+copyright assignment is required to contribute to the Rand project.
+
+For full authorship information, see the version control history.
+
+Except as otherwise noted (below and/or in individual files), Rand is
+licensed under the Apache License, Version 2.0 <LICENSE-APACHE> or
+<http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+<LICENSE-MIT> or <http://opensource.org/licenses/MIT>, at your option.
+
+The Rand project includes code from the Rust project
+published under these same licenses.
--- /dev/null
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+edition = "2018"
+name = "rand_pcg"
+version = "0.3.1"
+authors = ["The Rand Project Developers"]
+description = "Selected PCG random number generators\n"
+homepage = "https://rust-random.github.io/book"
+documentation = "https://docs.rs/rand_pcg"
+readme = "README.md"
+keywords = ["random", "rng", "pcg"]
+categories = ["algorithms", "no-std"]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-random/rand"
+[dependencies.rand_core]
+version = "0.6.0"
+
+[dependencies.serde]
+version = "1"
+features = ["derive"]
+optional = true
+[dev-dependencies.bincode]
+version = "1.1.4"
+
+[features]
+serde1 = ["serde"]
--- /dev/null
+[package]
+name = "rand_pcg"
+version = "0.3.1"
+authors = ["The Rand Project Developers"]
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+repository = "https://github.com/rust-random/rand"
+documentation = "https://docs.rs/rand_pcg"
+homepage = "https://rust-random.github.io/book"
+description = """
+Selected PCG random number generators
+"""
+keywords = ["random", "rng", "pcg"]
+categories = ["algorithms", "no-std"]
+edition = "2018"
+
+[features]
+serde1 = ["serde"]
+
+[dependencies]
+rand_core = { path = "../rand_core", version = "0.6.0" }
+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
+# Versions prior to 1.1.4 had incorrect minimal dependencies.
+bincode = { version = "1.1.4" }
--- /dev/null
+ Apache License
+ Version 2.0, January 2004
+ https://www.apache.org/licenses/
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+ risks associated with Your exercise of permissions under this License.
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+8. Limitation of Liability. In no event and under no legal theory,
+ whether in tort (including negligence), contract, or otherwise,
+ unless required by applicable law (such as deliberate and grossly
+ negligent acts) or agreed to in writing, shall any Contributor be
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+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+ To apply the Apache License to your work, attach the following
+ boilerplate notice, with the fields enclosed by brackets "[]"
+ replaced with your own identifying information. (Don't include
+ the brackets!) The text should be enclosed in the appropriate
+ comment syntax for the file format. We also recommend that a
+ file or class name and description of purpose be included on the
+ same "printed page" as the copyright notice for easier
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+
+Copyright [yyyy] [name of copyright owner]
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
--- /dev/null
+Copyright (c) 2014-2017 Melissa O'Neill and PCG Project contributors
+Copyright 2018 Developers of the Rand project
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
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+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
--- /dev/null
+# rand_pcg
+
+[](https://github.com/rust-random/rand/actions)
+[](https://crates.io/crates/rand_pcg)
+[](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)
+
+Implements a selection of PCG random number generators.
+
+> PCG is a family of simple fast space-efficient statistically good algorithms
+> for random number generation. [Melissa O'Neill, Harvey Mudd College, 2014].
+
+The PCG algorithms are not suitable for cryptographic uses, but perform well
+in statistical tests, use little memory and are fairly fast.
+See the [pcg-random website](http://www.pcg-random.org/).
+
+This crate depends on [rand_core](https://crates.io/crates/rand_core) and is
+part of the [Rand project](https://github.com/rust-random/rand).
+
+Links:
+
+- [API documentation (master)](https://rust-random.github.io/rand/rand_pcg)
+- [API documentation (docs.rs)](https://docs.rs/rand_pcg)
+- [Changelog](https://github.com/rust-random/rand/blob/master/rand_pcg/CHANGELOG.md)
+
+
+## Crate Features
+
+`rand_pcg` is `no_std` compatible by default.
+
+The `serde1` feature includes implementations of `Serialize` and `Deserialize`
+for the included RNGs.
+
+## License
+
+`rand_pcg` is distributed under the terms of both the MIT license and the
+Apache License (Version 2.0).
+
+See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT), and
+[COPYRIGHT](COPYRIGHT) for details.
--- /dev/null
+// 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.
+
+//! The PCG random number generators.
+//!
+//! This is a native Rust implementation of a small selection of PCG generators.
+//! The primary goal of this crate is simple, minimal, well-tested code; in
+//! other words it is explicitly not a goal to re-implement all of PCG.
+//!
+//! This crate provides:
+//!
+//! - `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).
+//! - `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.
+//!
+//! 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
+//! be considered a breaking change to the crate).
+
+#![doc(
+ html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk.png",
+ html_favicon_url = "https://www.rust-lang.org/favicon.ico",
+ html_root_url = "https://rust-random.github.io/rand/"
+)]
+#![deny(missing_docs)]
+#![deny(missing_debug_implementations)]
+#![no_std]
+
+#[cfg(not(target_os = "emscripten"))] mod pcg128;
+mod pcg64;
+
+#[cfg(not(target_os = "emscripten"))]
+pub use self::pcg128::{Lcg128Xsl64, Mcg128Xsl64, Pcg64, Pcg64Mcg};
+pub use self::pcg64::{Lcg64Xsh32, Pcg32};
--- /dev/null
+// Copyright 2018 Developers of the Rand project.
+// Copyright 2017 Paul Dicker.
+// Copyright 2014-2017 Melissa O'Neill and PCG Project contributors
+//
+// 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.
+
+//! PCG random number generators
+
+// This is the default multiplier used by PCG for 128-bit state.
+const MULTIPLIER: u128 = 0x2360_ED05_1FC6_5DA4_4385_DF64_9FCC_F645;
+
+use core::fmt;
+use rand_core::{le, Error, RngCore, SeedableRng};
+#[cfg(feature = "serde1")] use serde::{Deserialize, Serialize};
+
+/// 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.
+///
+/// Note that two generators with different stream parameters may be closely
+/// correlated.
+#[derive(Clone, PartialEq, Eq)]
+#[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 {
+ /// Multi-step advance functions (jump-ahead, jump-back)
+ ///
+ /// The method used here is based on Brown, "Random Number Generation
+ /// with Arbitrary Stride,", Transactions of the American Nuclear
+ /// Society (Nov. 1994). The algorithm is very similar to fast
+ /// exponentiation.
+ ///
+ /// Even though delta is an unsigned integer, we can pass a
+ /// signed integer to go backwards, it just goes "the long way round".
+ ///
+ /// Using this function is equivalent to calling `next_64()` `delta`
+ /// number of times.
+ #[inline]
+ pub fn advance(&mut self, delta: u128) {
+ let mut acc_mult: u128 = 1;
+ let mut acc_plus: u128 = 0;
+ let mut cur_mult = MULTIPLIER;
+ let mut cur_plus = self.increment;
+ let mut mdelta = delta;
+
+ while mdelta > 0 {
+ if (mdelta & 1) != 0 {
+ acc_mult = acc_mult.wrapping_mul(cur_mult);
+ acc_plus = acc_plus.wrapping_mul(cur_mult).wrapping_add(cur_plus);
+ }
+ cur_plus = cur_mult.wrapping_add(1).wrapping_mul(cur_plus);
+ cur_mult = cur_mult.wrapping_mul(cur_mult);
+ mdelta /= 2;
+ }
+ self.state = acc_mult.wrapping_mul(self.state).wrapping_add(acc_plus);
+ }
+
+ /// Construct an instance compatible with PCG seed and stream.
+ ///
+ /// Note that two generators with different stream parameters may be closely
+ /// correlated.
+ ///
+ /// PCG specifies the following 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).
+///
+/// Permuted Congruential Generator with 128-bit state, internal Multiplicative
+/// 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, 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.
+#[derive(Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
+pub struct Mcg128Xsl64 {
+ state: u128,
+}
+
+/// A friendly name for [`Mcg128Xsl64`] (also known as `pcg64_fast`).
+pub type Pcg64Mcg = Mcg128Xsl64;
+
+impl Mcg128Xsl64 {
+ /// Multi-step advance functions (jump-ahead, jump-back)
+ ///
+ /// The method used here is based on Brown, "Random Number Generation
+ /// with Arbitrary Stride,", Transactions of the American Nuclear
+ /// Society (Nov. 1994). The algorithm is very similar to fast
+ /// exponentiation.
+ ///
+ /// Even though delta is an unsigned integer, we can pass a
+ /// signed integer to go backwards, it just goes "the long way round".
+ ///
+ /// Using this function is equivalent to calling `next_64()` `delta`
+ /// number of times.
+ #[inline]
+ pub fn advance(&mut self, delta: u128) {
+ let mut acc_mult: u128 = 1;
+ let mut acc_plus: u128 = 0;
+ let mut cur_mult = MULTIPLIER;
+ let mut cur_plus: u128 = 0;
+ let mut mdelta = delta;
+
+ while mdelta > 0 {
+ if (mdelta & 1) != 0 {
+ acc_mult = acc_mult.wrapping_mul(cur_mult);
+ acc_plus = acc_plus.wrapping_mul(cur_mult).wrapping_add(cur_plus);
+ }
+ cur_plus = cur_mult.wrapping_add(1).wrapping_mul(cur_plus);
+ cur_mult = cur_mult.wrapping_mul(cur_mult);
+ mdelta /= 2;
+ }
+ self.state = acc_mult.wrapping_mul(self.state).wrapping_add(acc_plus);
+ }
+
+ /// Construct an instance compatible with PCG seed.
+ ///
+ /// Note that PCG specifies a default value for the parameter:
+ ///
+ /// - `state = 0xcafef00dd15ea5e5`
+ pub fn new(state: u128) -> Self {
+ // Force low bit to 1, as in C version (C++ uses `state | 3` instead).
+ Mcg128Xsl64 { state: state | 1 }
+ }
+}
+
+// Custom Debug implementation that does not expose the internal state
+impl fmt::Debug for Mcg128Xsl64 {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "Mcg128Xsl64 {{}}")
+ }
+}
+
+/// We use a single 126-bit seed to initialise the state and select a stream.
+/// Two `seed` bits (lowest order of last byte) are ignored.
+impl SeedableRng for Mcg128Xsl64 {
+ type Seed = [u8; 16];
+
+ fn from_seed(seed: Self::Seed) -> Self {
+ // Read as if a little-endian u128 value:
+ let mut seed_u64 = [0u64; 2];
+ le::read_u64_into(&seed, &mut seed_u64);
+ let state = u128::from(seed_u64[0]) |
+ u128::from(seed_u64[1]) << 64;
+ Mcg128Xsl64::new(state)
+ }
+}
+
+impl RngCore for Mcg128Xsl64 {
+ #[inline]
+ fn next_u32(&mut self) -> u32 {
+ self.next_u64() as u32
+ }
+
+ #[inline]
+ fn next_u64(&mut self) -> u64 {
+ self.state = self.state.wrapping_mul(MULTIPLIER);
+ 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(())
+ }
+}
+
+#[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]);
+ }
+}
--- /dev/null
+// Copyright 2018 Developers of the Rand project.
+// Copyright 2017 Paul Dicker.
+// Copyright 2014-2017 Melissa O'Neill and PCG Project contributors
+//
+// 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.
+
+//! PCG random number generators
+
+use core::fmt;
+use rand_core::{impls, le, Error, RngCore, SeedableRng};
+#[cfg(feature = "serde1")] use serde::{Deserialize, Serialize};
+
+// This is the default multiplier used by PCG for 64-bit state.
+const MULTIPLIER: u64 = 6364136223846793005;
+
+/// A PCG random number generator (XSH RR 64/32 (LCG) variant).
+///
+/// Permuted Congruential Generator with 64-bit state, internal Linear
+/// Congruential Generator, and 32-bit output via "xorshift high (bits),
+/// random rotation" output function.
+///
+/// This is a 64-bit LCG with explicitly chosen stream with the PCG-XSH-RR
+/// output function. This combination is the standard `pcg32`.
+///
+/// Despite the name, this implementation uses 16 bytes (128 bit) space
+/// comprising 64 bits of state and 64 bits stream selector. These are both set
+/// by `SeedableRng`, using a 128-bit seed.
+///
+/// Note that two generators with different stream parameter may be closely
+/// correlated.
+#[derive(Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
+pub struct Lcg64Xsh32 {
+ state: u64,
+ increment: u64,
+}
+
+/// [`Lcg64Xsh32`] is also officially known as `pcg32`.
+pub type Pcg32 = Lcg64Xsh32;
+
+impl Lcg64Xsh32 {
+ /// Multi-step advance functions (jump-ahead, jump-back)
+ ///
+ /// The method used here is based on Brown, "Random Number Generation
+ /// with Arbitrary Stride,", Transactions of the American Nuclear
+ /// Society (Nov. 1994). The algorithm is very similar to fast
+ /// exponentiation.
+ ///
+ /// Even though delta is an unsigned integer, we can pass a
+ /// signed integer to go backwards, it just goes "the long way round".
+ ///
+ /// Using this function is equivalent to calling `next_32()` `delta`
+ /// number of times.
+ #[inline]
+ pub fn advance(&mut self, delta: u64) {
+ let mut acc_mult: u64 = 1;
+ let mut acc_plus: u64 = 0;
+ let mut cur_mult = MULTIPLIER;
+ let mut cur_plus = self.increment;
+ let mut mdelta = delta;
+
+ while mdelta > 0 {
+ if (mdelta & 1) != 0 {
+ acc_mult = acc_mult.wrapping_mul(cur_mult);
+ acc_plus = acc_plus.wrapping_mul(cur_mult).wrapping_add(cur_plus);
+ }
+ cur_plus = cur_mult.wrapping_add(1).wrapping_mul(cur_plus);
+ cur_mult = cur_mult.wrapping_mul(cur_mult);
+ mdelta /= 2;
+ }
+ self.state = acc_mult.wrapping_mul(self.state).wrapping_add(acc_plus);
+ }
+
+ /// Construct an instance compatible with PCG seed and stream.
+ ///
+ /// Note that two generators with different stream parameters may be closely
+ /// correlated.
+ ///
+ /// PCG specifies the following default values for both parameters:
+ ///
+ /// - `state = 0xcafef00dd15ea5e5`
+ /// - `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;
+ Lcg64Xsh32::from_state_incr(state, increment)
+ }
+
+ #[inline]
+ fn from_state_incr(state: u64, increment: u64) -> Self {
+ let mut pcg = Lcg64Xsh32 { 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 Lcg64Xsh32 {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "Lcg64Xsh32 {{}}")
+ }
+}
+
+/// We use a single 127-bit seed to initialise the state and select a stream.
+/// One `seed` bit (lowest bit of `seed[8]`) is ignored.
+impl SeedableRng for Lcg64Xsh32 {
+ type Seed = [u8; 16];
+
+ fn from_seed(seed: Self::Seed) -> Self {
+ let mut seed_u64 = [0u64; 2];
+ le::read_u64_into(&seed, &mut seed_u64);
+
+ // The increment must be odd, hence we discard one bit:
+ Lcg64Xsh32::from_state_incr(seed_u64[0], seed_u64[1] | 1)
+ }
+}
+
+impl RngCore for Lcg64Xsh32 {
+ #[inline]
+ fn next_u32(&mut self) -> u32 {
+ let state = self.state;
+ self.step();
+
+ // Output function XSH RR: xorshift high (bits), followed by a random rotate
+ // Constants are for 64-bit state, 32-bit output
+ const ROTATE: u32 = 59; // 64 - 5
+ const XSHIFT: u32 = 18; // (5 + 32) / 2
+ const SPARE: u32 = 27; // 64 - 32 - 5
+
+ let rot = (state >> ROTATE) as u32;
+ let xsh = (((state >> XSHIFT) ^ state) >> SPARE) as u32;
+ xsh.rotate_right(rot)
+ }
+
+ #[inline]
+ fn next_u64(&mut self) -> u64 {
+ impls::next_u64_via_u32(self)
+ }
+
+ #[inline]
+ fn fill_bytes(&mut self, dest: &mut [u8]) {
+ impls::fill_bytes_via_next(self, dest)
+ }
+
+ #[inline]
+ fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+ self.fill_bytes(dest);
+ Ok(())
+ }
+}
--- /dev/null
+use rand_core::{RngCore, SeedableRng};
+use rand_pcg::{Lcg128Xsl64, Pcg64};
+
+#[test]
+fn test_lcg128xsl64_advancing() {
+ for seed in 0..20 {
+ let mut rng1 = Lcg128Xsl64::seed_from_u64(seed);
+ let mut rng2 = rng1.clone();
+ for _ in 0..20 {
+ rng1.next_u64();
+ }
+ rng2.advance(20);
+ assert_eq!(rng1, rng2);
+ }
+}
+
+#[test]
+fn test_lcg128xsl64_construction() {
+ // Test that various construction techniques produce a working RNG.
+ #[rustfmt::skip]
+ 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::{BufReader, BufWriter};
+
+ 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());
+ }
+}
--- /dev/null
+use rand_core::{RngCore, SeedableRng};
+use rand_pcg::{Lcg64Xsh32, Pcg32};
+
+#[test]
+fn test_lcg64xsh32_advancing() {
+ for seed in 0..20 {
+ let mut rng1 = Lcg64Xsh32::seed_from_u64(seed);
+ let mut rng2 = rng1.clone();
+ for _ in 0..20 {
+ rng1.next_u32();
+ }
+ rng2.advance(20);
+ assert_eq!(rng1, rng2);
+ }
+}
+
+#[test]
+fn test_lcg64xsh32_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];
+ let mut rng1 = Lcg64Xsh32::from_seed(seed);
+ assert_eq!(rng1.next_u64(), 1204678643940597513);
+
+ let mut rng2 = Lcg64Xsh32::from_rng(&mut rng1).unwrap();
+ assert_eq!(rng2.next_u64(), 12384929573776311845);
+
+ let mut rng3 = Lcg64Xsh32::seed_from_u64(0);
+ assert_eq!(rng3.next_u64(), 18195738587432868099);
+
+ // This is the same as Lcg64Xsh32, so we only have a single test:
+ let mut rng4 = Pcg32::seed_from_u64(0);
+ assert_eq!(rng4.next_u64(), 18195738587432868099);
+}
+
+#[test]
+fn test_lcg64xsh32_true_values() {
+ // Numbers copied from official test suite.
+ let mut rng = Lcg64Xsh32::new(42, 54);
+
+ let mut results = [0u32; 6];
+ for i in results.iter_mut() {
+ *i = rng.next_u32();
+ }
+ let expected: [u32; 6] = [
+ 0xa15c02b7, 0x7b47f409, 0xba1d3330, 0x83d2f293, 0xbfa4784b, 0xcbed606e,
+ ];
+ assert_eq!(results, expected);
+}
+
+#[cfg(feature = "serde1")]
+#[test]
+fn test_lcg64xsh32_serde() {
+ use bincode;
+ use std::io::{BufReader, BufWriter};
+
+ let mut rng = Lcg64Xsh32::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: Lcg64Xsh32 =
+ bincode::deserialize_from(&mut read).expect("Could not deserialize");
+
+ for _ in 0..16 {
+ assert_eq!(rng.next_u64(), deserialized.next_u64());
+ }
+}
--- /dev/null
+use rand_core::{RngCore, SeedableRng};
+use rand_pcg::{Mcg128Xsl64, Pcg64Mcg};
+
+#[test]
+fn test_mcg128xsl64_advancing() {
+ for seed in 0..20 {
+ let mut rng1 = Mcg128Xsl64::seed_from_u64(seed);
+ let mut rng2 = rng1.clone();
+ for _ in 0..20 {
+ rng1.next_u64();
+ }
+ rng2.advance(20);
+ assert_eq!(rng1, rng2);
+ }
+}
+
+#[test]
+fn test_mcg128xsl64_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];
+ let mut rng1 = Mcg128Xsl64::from_seed(seed);
+ assert_eq!(rng1.next_u64(), 7071994460355047496);
+
+ let mut rng2 = Mcg128Xsl64::from_rng(&mut rng1).unwrap();
+ assert_eq!(rng2.next_u64(), 12300796107712034932);
+
+ let mut rng3 = Mcg128Xsl64::seed_from_u64(0);
+ assert_eq!(rng3.next_u64(), 6198063878555692194);
+
+ // This is the same as Mcg128Xsl64, so we only have a single test:
+ let mut rng4 = Pcg64Mcg::seed_from_u64(0);
+ assert_eq!(rng4.next_u64(), 6198063878555692194);
+}
+
+#[test]
+fn test_mcg128xsl64_true_values() {
+ // Numbers copied from official test suite (C version).
+ let mut rng = Mcg128Xsl64::new(42);
+
+ let mut results = [0u64; 6];
+ for i in results.iter_mut() {
+ *i = rng.next_u64();
+ }
+ let expected: [u64; 6] = [
+ 0x63b4a3a813ce700a,
+ 0x382954200617ab24,
+ 0xa7fd85ae3fe950ce,
+ 0xd715286aa2887737,
+ 0x60c92fee2e59f32c,
+ 0x84c4e96beff30017,
+ ];
+ assert_eq!(results, expected);
+}
+
+#[cfg(feature = "serde1")]
+#[test]
+fn test_mcg128xsl64_serde() {
+ use bincode;
+ use std::io::{BufReader, BufWriter};
+
+ let mut rng = Mcg128Xsl64::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: Mcg128Xsl64 =
+ bincode::deserialize_from(&mut read).expect("Could not deserialize");
+
+ for _ in 0..16 {
+ assert_eq!(rng.next_u64(), deserialized.next_u64());
+ }
+}
projects / platform / upstream / rust-rand_pcg.git / commitdiff