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factor::Decomposition: Use a flat vector representation

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~18% faster than BTreeMap, and ~5% faster than 'master'
This commit is contained in:
nicoo 2020-07-29 20:38:07 +02:00 • committed by Roy Ivy III
parent b8ef58c002
commit 30f9cf32f2
1 changed files with 4 additions and 25 deletions
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29
src/uu/factor/src/factor.rs
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@ -7,7 +7,6 @@
extern crate rand;
use std::cell::RefCell;
use std::fmt;
use crate::numeric::{Arithmetic, Montgomery};
@ -61,32 +60,9 @@ impl PartialEq for Decomposition {
true
}
#[derive(Clone, Debug, Eq, PartialEq)]
struct Decomposition(BTreeMap<u64, Exponent>);
impl Decomposition {
fn one() -> Decomposition {
Decomposition(BTreeMap::new())
}
fn add(&mut self, factor: u64, exp: Exponent) {
debug_assert!(exp > 0);
let n = *self.0.get(&factor).unwrap_or(&0);
self.0.insert(factor, exp + n);
}
#[cfg(test)]
fn product(&self) -> u64 {
self.0
.iter()
.fold(1, |acc, (p, exp)| acc * p.pow(*exp as u32))
}
}
impl Eq for Decomposition {}
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct Factors(RefCell<Decomposition>);
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct Factors(Decomposition);
@ -112,7 +88,10 @@ impl Factors {
impl fmt::Display for Factors {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
for (p, exp) in (self.0).0.iter() {
let mut v = (self.0).0.clone();
v.sort_unstable();
for (p, exp) in v.iter() {
for _ in 0..*exp {
write!(f, " {}", p)?
}