commit | e480a26ba3931e7fe07e3fa5317d701ac46be091 | [log] [tgz] |
---|---|---|
author | Diggory Hardy <dhardy@users.noreply.github.com> | Mon Dec 18 11:23:06 2017 +0000 |
committer | GitHub <noreply@github.com> | Mon Dec 18 11:23:06 2017 +0000 |
tree | f75dbead0312d7a719d1ffebe717abd0facff92b | |
parent | 1c6e2dc9f5281041c297f3e6e6b2ba773f54ea36 [diff] | |
parent | 144b0f11a4c44e856b88bedb90a2aa1c63b390ba [diff] |
Merge pull request #187 from tatref/patch-1 Fix name of argument in doc
A Rust library for random number generators and other randomness functionality.
Add this to your Cargo.toml
:
[dependencies] rand = "0.3"
and this to your crate root:
extern crate rand;
The ‘master’ branch tracks development code while the ‘0.3’ branch tracks the latest stable release. New features are currently being released in an “unstable channel”; if you wish to opt-in to the latest releases (expect more breaking changes in this channel) specify rand = "0.4.0-pre.0"
.
There is built-in support for a random number generator (RNG) associated with each thread stored in thread-local storage. This RNG can be accessed via thread_rng, or used implicitly via random. This RNG is normally randomly seeded from an operating-system source of randomness, e.g. /dev/urandom on Unix systems, and will automatically reseed itself from this source after generating 32 KiB of random data.
let tuple = rand::random::<(f64, char)>(); println!("{:?}", tuple)
use rand::Rng; let mut rng = rand::thread_rng(); if rng.gen() { // random bool println!("i32: {}, u32: {}", rng.gen::<i32>(), rng.gen::<u32>()) }
It is also possible to use other RNG types, which have a similar interface. The following uses the “ChaCha” algorithm instead of the default.
use rand::{Rng, ChaChaRng}; let mut rng = rand::ChaChaRng::new_unseeded(); println!("i32: {}, u32: {}", rng.gen::<i32>(), rng.gen::<u32>())
By default, rand
is built with all stable features available. The following optional features are available:
i128_support
enables support for generating u128
and i128
values
nightly
enables all unstable features (i128_support
)
std
enabled by default; by setting “default-features = false” no_std
mode is activated; this removes features depending on std
functionality:
- `OsRng` is entirely unavailable - `JitterRng` code is still present, but a nanosecond timer must be provided via `JitterRng::new_with_timer` - Since no external entropy is available, it is not possible to create generators with fresh seeds (user must provide entropy) - `thread_rng`, `weak_rng` and `random` are all disabled - exponential, normal and gamma type distributions are unavailable since `exp` and `log` functions are not provided in `core` - any code requiring `Vec` or `Box`
alloc
can be used instead of std
to provide Vec
and Box
Unfortunately, cargo test
does not test everything. The following tests are recommended:
# Basic tests for rand and sub-crates cargo test --all # Test no_std support (build only since nearly all tests require std) cargo build --all --no-default-features # Test 128-bit support (requires nightly) cargo test --all --features nightly # Benchmarks (requires nightly) cargo bench # or just to test the benchmark code: cargo test --benches
derive(Rand)
You can derive the Rand
trait for your custom type via the #[derive(Rand)]
directive. To use this first add this to your Cargo.toml:
rand = "0.3" rand_derive = "0.3"
Next in your crate:
extern crate rand; #[macro_use] extern crate rand_derive; #[derive(Rand, Debug)] struct MyStruct { a: i32, b: u32, } fn main() { println!("{:?}", rand::random::<MyStruct>()); }
rand
is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE, and LICENSE-MIT for details.