Add example for initializing a PCG RNG

rand_pcg/CHANGELOG.md

@@ -6,6 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 - Add `Lcg128CmDxsm64` generator compatible with NumPy's `PCG64DXSM` (#1202)
+- Add examples for initializing the RNGs
 
 ## [0.3.1] - 2021-06-15
 - Add `advance` methods to RNGs (#1111)

rand_pcg/Cargo.toml

@@ -26,6 +26,7 @@ rand_core = { path = "../rand_core", version = "0.7.0" }
 serde = { version = "1", features = ["derive"], optional = true }
 
 [dev-dependencies]
+rand = { path = "..", version = "0.9" }
 # 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.

rand_pcg/src/lib.rs

@@ -1,4 +1,4 @@
-// Copyright 2018 Developers of the Rand project.
+// Copyright 2018-2023 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
@@ -27,6 +27,29 @@
 //! 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).
+//!
+//! # Example
+//!
+//! To initialize a generator, use the [`SeedableRng`][rand_core::SeedableRng] trait:
+//!
+//! ```
+//! use rand_core::{SeedableRng, RngCore};
+//! use rand_pcg::Pcg64Mcg;
+//!
+//! let mut rng = Pcg64Mcg::seed_from_u64(0);
+//! let x: u32 = rng.next_u32();
+//! ```
+//!
+//! The functionality of this crate is implemented using traits from the `rand_core` crate, but you may use the `rand`
+//! crate for further functionality to initialize the generator from various sources and to generate random values:
+//!
+//! ```
+//! use rand::{Rng, SeedableRng};
+//! use rand_pcg::Pcg64Mcg;
+//!
+//! let mut rng = Pcg64Mcg::from_entropy();
+//! let x: f64 = rng.gen();
+//! ```
 
 #![doc(
     html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk.png",