Fixed Point Number Library

The Fixed Point Number Library provides a library to use fixed-point numbers in Sway. It has 3 distinct unsigned types: UFP32, UFP64 and UFP128 as well as 3 signed types IFP64, IFP128 and IFP256. These types are stack allocated.

This type is stored as a u32, u64 or U128 under the hood. Therefore the size can be known at compile time and the length is static.

For implementation details on the Fixed Point Number Library please see the Sway Libs Docs.

Importing the Fixed Point Number Library

In order to use the Fixed Point Number Library, Sway Libs must be added to the Forc.toml file and then imported into your Sway project. To add Sway Libs as a dependency to the Forc.toml file in your project please see the Getting Started.

To import the Fixed Point Number Library to your Sway Smart Contract, add the following to your Sway file:

use sway_libs::fixed_point::*;

Supported Fixed Point Numbers

Signed Fixed Point Numbers

We currently support the following signed Fixed Point numbers:

IFP64
IFP128
IFP256

In order to use the IFP64, IFP128 or IFP256 types, import them into your Sway project like so:

use sway_libs::fixed_point::{ifp128::IFP128, ifp256::IFP256, ifp64::IFP64,};

Unsigned Fixed Point Numbers

We currently support the following unsigned Fixed Point numbers:

UFP32
UFP64
UFP128

In order to use the UFP32, UFP64 or UFP128 types, import them into your Sway project like so:

use sway_libs::fixed_point::{ufp128::UFP128, ufp32::UFP32, ufp64::UFP64,};

Basic Functionality

Instantiating a New Fixed Point Number

Once imported, any signed or unsigned Fixed Point number type can be instantiated by defining a new variable and calling the from function.

    let mut ufp32_value = UFP32::from(0u32);
    let mut ufp64_value = UFP64::from(0u64);
    let mut ufp128_value = UFP128::from((0u64, 0u64));

Basic mathematical Functions

Basic arithmetic operations are working as usual.

fn add_ufp(val1: UFP64, val2: UFP64) {
    let result: UFP64 = val1 + val2;
}

fn subtract_ufp(val1: UFP64, val2: UFP64) {
    let result: UFP64 = val1 - val2;
}

fn multiply_ufp(val1: UFP64, val2: UFP64) {
    let result: UFP64 = val1 * val2;
}

fn divide_ufp(val1: UFP64, val2: UFP64) {
    let result: UFP64 = val1 / val2;
}

Advanced mathematical Functions Supported

We currently support the following advanced mathematical functions:

Exponential

    let ten = UFP64::from_uint(10);
    let res = UFP64::exp(ten);

Square Root

    let ufp64_169 = UFP64::from_uint(169);
    let res = UFP64::sqrt(ufp64_169);

Power

    let five = UFP64::from_uint(5);
    let res = five.pow(3u32);

Sway Libraries