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perf/factor ~ improve factor() quotient and loop comparison (~6% time improvement)

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Roy Ivy III 2020-10-08 18:58:09 -05:00
parent 368f47381b
commit 6eea8c5f30
1 changed files with 5 additions and 5 deletions
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10
src/uu/factor/src/factor.rs
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@ -171,19 +171,19 @@ pub fn factor(num: u64) -> Factors {
let mut gcd_queue = Decomposition::one(); let mut gcd_queue = Decomposition::one();
let quotient = factor / divisor; let quotient = factor / divisor;
if quotient == divisor { let mut trivial_gcd = quotient == divisor;
if trivial_gcd {
gcd_queue.add(divisor, exp + 1); gcd_queue.add(divisor, exp + 1);
} else { } else {
gcd_queue.add(divisor, exp); gcd_queue.add(divisor, exp);
gcd_queue.add(quotient, exp); gcd_queue.add(quotient, exp);
} }
let mut non_trivial_gcd = quotient != divisor; while !trivial_gcd {
while non_trivial_gcd {
debug_assert_eq!(factor, gcd_queue.product()); debug_assert_eq!(factor, gcd_queue.product());
let mut tmp = Decomposition::one(); let mut tmp = Decomposition::one();
non_trivial_gcd = false; trivial_gcd = true;
for i in 0..gcd_queue.0.len() - 1 { for i in 0..gcd_queue.0.len() - 1 {
let (mut a, exp_a) = gcd_queue.0[i]; let (mut a, exp_a) = gcd_queue.0[i];
let (mut b, exp_b) = gcd_queue.0[i + 1]; let (mut b, exp_b) = gcd_queue.0[i + 1];
@ -194,7 +194,7 @@ pub fn factor(num: u64) -> Factors {
let g = gcd(a, b); let g = gcd(a, b);
if g != 1 { if g != 1 {
non_trivial_gcd = true; trivial_gcd = false;
a /= g; a /= g;
b /= g; b /= g;
} }