float16
This a fork of half, which removes most dependencies and fixing minor correctness issues. This has no affiliation to half.
This crate implements a half-precision floating point f16 type for Rust implementing the IEEE 754-2008 standard binary16 a.k.a "half" format, as well as a bf16 type implementing the bfloat16 format.
This is a minimal variant which removes some features and introduce many build dependencies. It also allows the crate to run on much older versions of rustc (1.60+) while retaining the performance, still using intrinsics when available (Rust 1.63+ on ARM64 and Rust 1.68+ on x86/x86_64). If you would like to use this, we recommend converting to or from the analogous types in half, which this crate was based off of.
Usage
The f16 and bf16 types attempt to match existing Rust floating point type functionality where possible, and provides both conversion operations (such as to/from f32 and f64) and basic arithmetic operations. Hardware support for these operations will be used whenever hardware support is available—either through instrinsics or targeted assembly—although a nightly Rust toolchain may be required for some hardware.
This crate provides no_std support so can easily be used in embedded code where a smaller float format is most useful.
Requires Rust 1.60 or greater.
See the crate documentation for more details.
Hardware support
The following list details hardware support for floating point types in this crate. When using std
library, runtime CPU target detection will be used. To get the most performance benefits, compile
for specific CPU features which avoids the runtime overhead and works in a no_std environment.
| Architecture | CPU Target Feature | Notes |
|---|---|---|
x86/x86_64 |
f16c |
This supports conversion to/from f16 only (including vector SIMD) and does not support any bf16 or arithmetic operations. |
aarch64 |
fp16 |
This supports all operations on f16 only. |
loongarch64 |
lsx |
This supports conversion to/from f16 only (including vector SIMD) and does not support any bf16 or arithmetic operations. |
More Documentation
License
All files in this library are dual-licensed and distributed under the terms of either of:
- MIT License (http://opensource.org/licenses/MIT)
- Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
at your option.
Contributing
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.