timw4mail/rusty-numbers
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Merge branch 'master' of git.timshomepage.net:timw4mail/rusty-numbers
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Timothy Warren 2021-12-08 09:57:42 -05:00
commit 9f8e57f3d3
1 changed files with 2 additions and 34 deletions
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36
src/num.rs
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@ -2,7 +2,8 @@
//! //!
//! Home to the numeric trait chain of doom, aka `Unsigned` //! Home to the numeric trait chain of doom, aka `Unsigned`
#![allow(unused_comparisons)] #![allow(unused_comparisons)]
use core::cmp::{max, min, Ordering};
use core::cmp::Ordering;
use core::convert::TryFrom; use core::convert::TryFrom;
use core::fmt::Debug; use core::fmt::Debug;
use core::ops::{ use core::ops::{
@ -143,12 +144,6 @@ pub trait Unsigned:
/// Find the greatest common denominator of two numbers /// Find the greatest common denominator of two numbers
fn gcd(a: Self, b: Self) -> Self; fn gcd(a: Self, b: Self) -> Self;
/// Euclid gcd algorithm
fn e_gcd(a: Self, b: Self) -> Self;
/// Stein gcd algorithm
fn stein_gcd(a: Self, b: Self) -> Self;
/// Find the least common multiple of two numbers /// Find the least common multiple of two numbers
fn lcm(a: Self, b: Self) -> Self; fn lcm(a: Self, b: Self) -> Self;
} }
@ -246,31 +241,6 @@ macro_rules! impl_unsigned {
Self::gcd((b - a) >> 1, a) Self::gcd((b - a) >> 1, a)
} }
fn e_gcd(x: $Type, y: $Type) -> $Type {
let mut x = x;
let mut y = y;
while y != 0 {
let t = y;
y = x % y;
x = t;
}
x
}
fn stein_gcd(a: Self, b: Self) -> Self {
match ((a, b), (a & 1, b & 1)) {
((x, y), _) if x == y => y,
((0, x), _) | ((x, 0), _) => x,
((x, y), (0, 1)) | ((y, x), (1, 0)) => Self::stein_gcd(x >> 1, y),
((x, y), (0, 0)) => Self::stein_gcd(x >> 1, y >> 1) << 1,
((x, y), (1, 1)) => {
let (x, y) = (min(x, y), max(x, y));
Self::stein_gcd((y - x) >> 1, x)
}
_ => unreachable!(),
}
}
fn lcm(a: $Type, b: $Type) -> $Type { fn lcm(a: $Type, b: $Type) -> $Type {
if (a == 0 && b == 0) { if (a == 0 && b == 0) {
return 0; return 0;
@ -344,8 +314,6 @@ mod tests {
assert_eq!(u8::gcd(2, 2), 2); assert_eq!(u8::gcd(2, 2), 2);
assert_eq!(u8::gcd(2, 8), 2); assert_eq!(u8::gcd(2, 8), 2);
assert_eq!(u16::gcd(36, 48), 12); assert_eq!(u16::gcd(36, 48), 12);
assert_eq!(u16::e_gcd(36, 48), 12);
assert_eq!(u16::stein_gcd(36, 48), 12);
} }
#[test] #[test]