0.9.0

Upgrade guide

See https://rust-random.github.io/book/update-0.9.html

Changelog

Security and unsafe

• Policy: "rand is not a crypto library" (#1514)
• Remove fork-protection from ReseedingRng and ThreadRng. Instead, it is recommended to call ThreadRng::reseed on fork. (#1379)
• Use zerocopy to replace some unsafe code (#1349, #1393, #1446, #1502)

Dependencies

• Bump the MSRV to 1.63.0 (#1207, #1246, #1269, #1341, #1416, #1536); note that 1.60.0 may work for dependents when using --ignore-rust-version
• Update to rand_core v0.9.0 (#1558)

Features

• Support std feature without getrandom or rand_chacha (#1354)
• Enable feature small_rng by default (#1455)
• Remove implicit feature rand_chacha; use std_rng instead. (#1473)
• Rename feature serde1 to serde (#1477)
• Rename feature getrandom to os_rng (#1537)
• Add feature thread_rng (#1547)

API changes: rand_core traits

• Add fn RngCore::read_adapter implementing std::io::Read (#1267)
• Add trait CryptoBlockRng: BlockRngCore; make trait CryptoRng: RngCore (#1273)
• Add traits TryRngCore, TryCryptoRng (#1424, #1499)
• Rename fn SeedableRng::from_rng -> try_from_rng and add infallible variant fn from_rng (#1424)
• Rename fn SeedableRng::from_entropy -> from_os_rng and add fallible variant fn try_from_os_rng (#1424)
• Add bounds Clone and AsRef to associated type SeedableRng::Seed (#1491)

API changes: Rng trait and top-level fns

• Rename fn rand::thread_rng() to rand::rng() and remove from the prelude (#1506)
• Remove fn rand::random() from the prelude (#1506)
• Add top-level fns random_iter, random_range, random_bool, random_ratio, fill (#1488)
• Re-introduce fn Rng::gen_iter as random_iter (#1305, #1500)
• Rename fn Rng::gen to random to avoid conflict with the new gen keyword in Rust 2024 (#1438)
• Rename fns Rng::gen_range to random_range, gen_bool to random_bool, gen_ratio to random_ratio (#1505)
• Annotate panicking methods with #[track_caller] (#1442, #1447)

API changes: RNGs

• Fix <SmallRng as SeedableRng>::Seed size to 256 bits (#1455)
• Remove first parameter (rng) of ReseedingRng::new (#1533)

API changes: Sequences

• Split trait SliceRandom into IndexedRandom, IndexedMutRandom, SliceRandom (#1382)
• Add IndexedRandom::choose_multiple_array, index::sample_array (#1453, #1469)

API changes: Distributions: renames

• Rename module rand::distributions to rand::distr (#1470)
• Rename distribution Standard to StandardUniform (#1526)
• Move distr::Slice -> distr::slice::Choose, distr::EmptySlice -> distr::slice::Empty (#1548)
• Rename trait distr::DistString -> distr::SampleString (#1548)
• Rename distr::DistIter -> distr::Iter, distr::DistMap -> distr::Map (#1548)

API changes: Distributions

• Relax Sized bound on Distribution<T> for &D (#1278)
• Remove impl of Distribution<Option<T>> for StandardUniform (#1526)
• Let distribution StandardUniform support all NonZero* types (#1332)
• Fns {Uniform, UniformSampler}::{new, new_inclusive} return a Result (instead of potentially panicking) (#1229)
• Distribution Uniform implements TryFrom instead of From for ranges (#1229)
• Add UniformUsize (#1487)
• Remove support for generating isize and usize values with StandardUniform, Uniform (except via UniformUsize) and Fill and usage as a WeightedAliasIndex weight (#1487)
• Add impl DistString for distributions Slice<char> and Uniform<char> (#1315)
• Add fn Slice::num_choices (#1402)
• Add fn p() for distribution Bernoulli to access probability (#1481)

API changes: Weighted distributions

• Add pub module rand::distr::weighted, moving WeightedIndex there (#1548)
• Add trait weighted::Weight, allowing WeightedIndex to trap overflow (#1353)
• Add fns weight, weights, total_weight to distribution WeightedIndex (#1420)
• Rename enum WeightedError to weighted::Error, revising variants (#1382) and mark as #[non_exhaustive] (#1480)

API changes: SIMD

• Switch to std::simd, expand SIMD & docs (#1239)

Reproducibility-breaking changes

• Make ReseedingRng::reseed discard remaining data from the last block generated (#1379)
• Change fn SmallRng::seed_from_u64 implementation (#1203)
• Allow UniformFloat::new samples and UniformFloat::sample_single to yield high (#1462)
• Fix portability of distribution Slice (#1469)
• Make Uniform for usize portable via UniformUsize (#1487)
• Fix IndexdRandom::choose_multiple_weighted for very small seeds and optimize for large input length / low memory (#1530)

Reproducibility-breaking optimisations

• Optimize fn sample_floyd, affecting output of rand::seq::index::sample and rand::seq::SliceRandom::choose_multiple (#1277)
• New, faster algorithms for IteratorRandom::choose and choose_stable (#1268)
• New, faster algorithms for SliceRandom::shuffle and partial_shuffle (#1272)
• Optimize distribution Uniform: use Canon's method (single sampling) / Lemire's method (distribution sampling) for faster sampling (breaks value stability; #1287)
• Optimize fn sample_single_inclusive for floats (+~20% perf) (#1289)

Other optimisations

• Improve SmallRng initialization performance (#1482)
• Optimise SIMD widening multiply (#1247)

Other

• Add Cargo.lock.msrv file (#1275)
• Reformat with rustfmt and enforce (#1448)
• Apply Clippy suggestions and enforce (#1448, #1474)
• Move all benchmarks to new benches crate (#1329, #1439) and migrate to Criterion (#1490)

Documentation

• Improve ThreadRng related docs (#1257)
• Docs: enable experimental --generate-link-to-definition feature (#1327)
• Better doc of crate features, use doc_auto_cfg (#1411, #1450)

All PRs

• update Miri CI config by @RalfJung in #1223
• fix typo by @cuishuang in #1228
• Remove unused fields by @vks in #1184
• Make CryptoRngCore trait imply CryptoRng as well by @cbeck88 in #1230
• Deterministic Rayon monte carlo example by @masonk in #1236
• small deterministic example update by @TheIronBorn in #1240
• switch to std::simd, expand SIMD & docs by @TheIronBorn in #1239
• optimize simd widening mul by @TheIronBorn in #1247
• Mention disabling getrandom for wasm32-unknown-unknown in README by @golddranks in #1250
• Bump MSRV to 1.51.0 by @dhardy in #1246
• rand_core: update CHANGELOG for 0.6.4 by @dhardy in #1253
• Update listed rand_core version number by @atouchet in #1254
• Doc: improve random, thread_rng, ThreadRng docs by @dhardy in #1257
• Clarify documentation of choose_weighted(_mut) mentioning accurate behavior with floats by @ISibboI in #1245
• clarify shuffle docs by @RalfJung in #1259
• fix outdated choose_multiple_weighted docs by @TheIronBorn in #1237
• Update GitHub Actions by @dhardy in #1263
• Fix typo by @yaronf in #1264
• Remove redundant bounds by @steffahn in #1207
• SmallRng uses wrong seed_from_u64 implementation by @ironhaven in #1203
• gh-pages action: add id-token write permission by @dhardy in #1265
• Bump MSRV to 1.56 (Edition 2021) by @dhardy in #1269
• fill_via_chunks: mutate src on BE (small optimisation) by @dhardy in #1182
• Add read_adapter to avoid dynamic dispatch by @SUPERCILEX in #1267
• GitHub Workflows security hardening by @sashashura in #1274
• Add Criterion as dev-dependency, fix CI for MSRV and minimal-versions by @dhardy in #1275
• use partition_point in WeightedIndex by @TheIronBorn in #1276
• Simpler and faster implementation of Floyd's F2 by @ciphergoth in #1277
• Relax Sized bound on Distribution<T> for &D by @ChayimFriedman2 in #1278
• Added new versions of choose and choose_stable by @wainwrightmark in #1268
• Performance improvements for shuffle and partial_shuffle by @wainwrightmark in #1272
• Add note about floating point weights in update_weights docs by @arya2 in #1280
• Make Uniform constructors return a result by @vks in #1229
• Poisson returns -1 for small lambda by @tearne in #1284
• Rework CryptoRng by @newpavlov in #1273
• Don't run the random write test by @SUPERCILEX in #1294
• Poisson distribution falls into an infinite loop for parameter λ=∞ by @Thopic in #1291
• Use const generics in Dirichlet by @Armavica in #1292
• Uniform sampling: use C...

rand* 0.9.0-alpha.0

This is a pre-release. To depend on this version, use rand = "=0.9.0-alpha.0" to prevent automatic updates (which can be expected to include breaking changes).

Generators

• Change SmallRng::seed_from_u64 implementation (#1203)
• Replace SeedableRng impl for SmallRng with inherent methods, excluding fn from_seed (#1368)

Sequences

• Simpler and faster implementation of Floyd's F2 (#1277). This
  changes some outputs from rand::seq::index::sample and
  rand::seq::SliceRandom::choose_multiple.
• New, faster algorithms for IteratorRandom::choose and choose_stable (#1268)
• New, faster algorithms for SliceRandom::shuffle and partial_shuffle (#1272)
• Re-introduce Rng::gen_iter (#1305)
• Split trait SliceRandom into IndexedRandom, IndexedMutRandom, SliceRandom (#1382)

Distributions

• {Uniform, UniformSampler}::{new, new_inclusive} return a Result (instead of potentially panicking) (#1229)
• Uniform implements TryFrom instead of From for ranges (#1229)
• Uniform now uses Canon's method (single sampling) / Lemire's method (distribution sampling) for faster sampling (breaks value stability; #1287)
• Relax Sized bound on Distribution<T> for &D (#1278)
• Explicit impl of sample_single_inclusive (+~20% perf) (#1289)
• Impl DistString for Slice<char> and Uniform<char> (#1315)
• Let Standard support all NonZero* types (#1332)
• Add trait Weight, allowing WeightedIndex to trap overflow (#1353)
• Rename WeightedError to WeightError, revising variants (#1382)

SIMD

• Switch to std::simd, expand SIMD & docs (#1239)
• Optimise SIMD widening multipy (#1247)

Other

• Bump MSRV to 1.60.0 (#1207, #1246, #1269, #1341)
• Improve thread_rng related docs (#1257)
• Add Cargo.lock.msrv file (#1275)
• Docs: enable experimental --generate-link-to-definition feature (#1327)
• Use zerocopy to replace some unsafe code (#1349)
• Support std feature without getrandom or rand_chacha (#1354)

rand_distr-0.5.0-alpha.0

This is a pre-release. To depend on this version, use rand_distr = "=0.5.0-alpha.0" to prevent automatic updates (which can be expected to include breaking changes).

Additions

• Make distributions comparable with PartialEq (#1218)
• Add WeightedIndexTree (#1372)

Changes

• Target rand version 0.9.0-alpha.0
• Remove unused fields from Gamma, NormalInverseGaussian and Zipf distributions (#1184)
  This breaks serialization compatibility with older versions.
• Dirichlet now uses const generics, which means that its size is required at compile time (#1292)
• The Dirichlet::new_with_size constructor was removed (#1292)

Fixes

• Fix Knuth's method so Poisson doesn't return -1.0 for small lambda (#1284)
• Fix Poisson distribution instantiation so it return an error if lambda is infinite (#1291)
• Fix Dirichlet sample for small alpha values to avoid NaN samples (#1209)
• Fix infinite loop in Binomial distribution (#1325)