A Rust library for random number generation, featuring:
getrandomcrate and fast, convenient generation via
rand_core(see the book)
rand_distrand via the
It's also worth pointing out what
rand is not:
rand_distreach contain a lot of functionality.
Add this to your
[dependencies] rand = "0.8.0"
To get started using Rand, see The Book.
Rand is mature (suitable for general usage, with infrequent breaking releases which minimise breakage) but not yet at 1.0. We maintain compatibility with pinned versions of the Rust compiler (see below).
Current Rand versions are:
SeedableRng, and many small changes and fixes.
A detailed changelog is available for releases.
When upgrading to the next minor series (especially 0.4 → 0.5), we recommend reading the Upgrade Guide.
Rand has not yet reached 1.0 implying some breaking changes may arrive in the future (SemVer allows each 0.x.0 release to include breaking changes), but is considered mature: breaking changes are minimised and breaking releases are infrequent.
Rand libs have inter-dependencies and make use of the semver trick in order to make traits compatible across crate versions. (This is especially important for
SeedableRng.) A few crate releases are thus compatibility shims, depending on the next lib version (e.g.
0.3.1). This means, for example, that
rand_core_0_3_0::SeedableRng are distinct, incompatible traits, which can cause build errors. Usually, running
cargo update is enough to fix any issues.
Some versions of Rand crates have been yanked (“unreleased”). Where this occurs, the crate's CHANGELOG should be updated with a rationale, and a search on the issue tracker with the keyword
yank should uncover the motivation.
Since version 0.8, Rand requires Rustc version 1.36 or greater. Rand 0.7 requires Rustc 1.32 or greater while versions 0.5 require Rustc 1.22 or greater, and 0.4 and 0.3 (since approx. June 2017) require Rustc version 1.15 or greater. Subsets of the Rand code may work with older Rust versions, but this is not supported.
Continuous Integration (CI) will always test the minimum supported Rustc version (the MSRV). The current policy is that this can be updated in any Rand release if required, but the change must be noted in the changelog.
Rand is built with these features enabled by default:
stdenables functionality dependent on the
std) enables functionality requiring an allocator
std) is an optional dependency providing the code behind
std_rngenables inclusion of
random(the latter two also require that
Optionally, the following dependencies can be enabled:
logenables logging via the
Additionally, these features configure Rand:
small_rngenables inclusion of the
nightlyenables some optimizations requiring nightly Rust
simd_support(experimental) enables sampling of SIMD values (uniformly random SIMD integers and floats), requiring nightly Rust
Note that nightly features are not stable and therefore not all library and compiler versions will be compatible. This is especially true of Rand's experimental
Rand supports limited functionality in
no_std mode (enabled via
default-features = false). In this case,
from_entropy are unavailable (unless
getrandom is enabled), large parts of
seq are unavailable (unless
alloc is enabled), and
random are unavailable.
The WASM target
wasm32-unknown-unknown is not automatically supported by
getrandom. To solve this, either use a different target such as
wasm32-wasi or add a direct dependancy on
getrandom with the
Rand is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT, and COPYRIGHT for details.