README.md
1# num-bigint
2
3[](https://crates.io/crates/num-bigint)
4[](https://docs.rs/num-bigint)
5[](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
6[](https://github.com/rust-num/num-bigint/actions)
7
8Big integer types for Rust, `BigInt` and `BigUint`.
9
10## Usage
11
12Add this to your `Cargo.toml`:
13
14```toml
15[dependencies]
16num-bigint = "0.4"
17```
18
19## Features
20
21The `std` crate feature is enabled by default, and is mandatory before Rust
221.36 and the stabilized `alloc` crate. If you depend on `num-bigint` with
23`default-features = false`, you must manually enable the `std` feature yourself
24if your compiler is not new enough.
25
26### Random Generation
27
28`num-bigint` supports the generation of random big integers when the `rand`
29feature is enabled. To enable it include rand as
30
31```toml
32rand = "0.8"
33num-bigint = { version = "0.4", features = ["rand"] }
34```
35
36Note that you must use the version of `rand` that `num-bigint` is compatible
37with: `0.8`.
38
39## Releases
40
41Release notes are available in [RELEASES.md](RELEASES.md).
42
43## Compatibility
44
45The `num-bigint` crate is tested for rustc 1.31 and greater.
46
47## Alternatives
48
49While `num-bigint` strives for good performance in pure Rust code, other
50crates may offer better performance with different trade-offs. The following
51table offers a brief comparison to a few alternatives.
52
53| Crate | License | Min rustc | Implementation |
54| :--------------- | :------------- | :-------- | :------------- |
55| **`num-bigint`** | MIT/Apache-2.0 | 1.31 | pure rust |
56| [`ramp`] | Apache-2.0 | nightly | rust and inline assembly |
57| [`rug`] | LGPL-3.0+ | 1.37 | bundles [GMP] via [`gmp-mpfr-sys`] |
58| [`rust-gmp`] | MIT | stable? | links to [GMP] |
59| [`apint`] | MIT/Apache-2.0 | 1.26 | pure rust (unfinished) |
60
61[GMP]: https://gmplib.org/
62[`gmp-mpfr-sys`]: https://crates.io/crates/gmp-mpfr-sys
63[`rug`]: https://crates.io/crates/rug
64[`rust-gmp`]: https://crates.io/crates/rust-gmp
65[`ramp`]: https://crates.io/crates/ramp
66[`apint`]: https://crates.io/crates/apint
67
68## License
69
70Licensed under either of
71
72 * [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
73 * [MIT license](http://opensource.org/licenses/MIT)
74
75at your option.
76
77### Contribution
78
79Unless you explicitly state otherwise, any contribution intentionally submitted
80for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
81dual licensed as above, without any additional terms or conditions.
82
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