BFloat16

Brain floating point type for Swift.

Inspired by floating point implementations in

• Swift standard library
• SomeRandomiOSDev/Half
• starkat99/half-rs.

To install via the Swift Package Manager add the following line to your Package.swift file's dependencies:

.package(url: "https://github.com/ivarflakstad/BFloat16.swift.git", from: "1.0.0")

Disclaimer

I have never written Swift before. Is implementing a floating point type an odd choice for a first project in a new language? Yes. Yes it is. I suddenly had the need for bfloat in Swift, it didn't exist, and here we are.

That does not automatically mean this implementation is bad, in fact I think it's pretty decent, but I can't guarantee there are no subtle bugs. The testing is pretty decent though.

Usage

Import BFloat16:

import BFloat16

After importing, use the imported BFloat16 type exactly like you'd use Swift's builtin Float, Double, or Float80 types.

func printDouble(value: BFloat16) {
    print(value * 2.0)
}
printDouble(7.891)

> 15.782

Also supports SIMD

var actual = SIMD4<BFloat16>(1.0, 2.0, 3.0, 4.0)
for _ in 0...10 {
  actual += actual
}
let expected = SIMD4<BFloat16>(2048.0, 4096.0, 6144.0, 8192.0)
assert(actual == expected)

License

BFloat16 is available under the MIT license. See the LICENSE file for more info.