special: Special functions

[github-actions]

On 2022-05-28 @recmo wrote in 1ec2e50 “Recognize new tags”:

Special functions
Factorial
Extended GCD and LCM
https://en.wikipedia.org/wiki/Euler%27s_totient_function
https://en.wikipedia.org/wiki/Carmichael_function
https://en.wikipedia.org/wiki/Jordan%27s_totient_function
Feature parity with GMP:
https://gmplib.org/manual/Integer-Functions.html#Integer-Functions

use crate::Uint;

// FEATURE: Special functions
// * Factorial
// * Extended GCD and LCM
// * https://en.wikipedia.org/wiki/Euler%27s_totient_function
// * https://en.wikipedia.org/wiki/Carmichael_function
// * https://en.wikipedia.org/wiki/Jordan%27s_totient_function
// * Feature parity with GMP:
//   * https://gmplib.org/manual/Integer-Functions.html#Integer-Functions

impl<const BITS: usize, const LIMBS: usize> Uint<BITS, LIMBS> {
    /// Returns `true` if and only if `self == 2^k` for some `k`.
    #[must_use]
    pub fn is_power_of_two(self) -> bool {

From src/special.rs:3