Crate hyperoperation

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Expand description

Hyperoperation

This crate allows to calculate and format hyperoperation, sometimes known as Knuth’s up-arrow notation, which is a way to define very large numbers, such as famous 3↑↑↑3.

Features

  • Calculate value of hyperoperations (more and more)
  • Format hyperoperations with Knuth’s up-arrow notation (more)
  • Use any unsigned numeric type for calculation fitting some conditions, such as BigUint

Examples

Simple calculation:

assert_eq!(
    hyperoperation::<u64>(&3, 3, 2), // 3 ↑↑ 3
    7625597484987
);

Using BigUint to handle big results without overflowing:

use num_bigint::BigUint;

let result = hyperoperation::<BigUint>(&5u8.into(), 3u8.into(), 2); // 5 ↑↑ 3
println!("Result:\n{result}");
assert_eq!(
    result % BigUint::from(100_000_000u32),
    8203125u32.into()
);

Using Hyperoperation struct and formatting it with Knuth’s up-arrow notation:

let expr = Hyperoperation::<u64>::new(3, 3, 2); // Represents 3 ↑↑ 3
let result = expr.clone().evaluate(); // Calculate the value of 3 ↑↑ 3

println!("{expr} = {result}");
assert_eq!(result, 7625597484987);
assert_eq!(format!("{expr}"), "3 ↑↑ 3");

Structs

Traits

  • NumForKnuth
    Number that can be used either as the first or second number in hyperoperation. Automatically implemented for all fitting numbers.

Functions