never underestimate a jit

primes/rust/Cargo.toml

@@ -6,4 +6,10 @@ edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-[dependencies]
+[dependencies]
+
+[profile.dev]
+opt-level = 3
+
+[profile.release]
+opt-level = 3

primes/rust/src/main.rs

@@ -3,14 +3,17 @@ use std::time::{SystemTime};
 fn main() {
     let mut times = Vec::new();
 
-    for i in 0..10 {
+    for i in 0..2 {
         println!("Starting run {}", i);
         let start = SystemTime::now();
         let _ = primes(10_000_000);
+
         let time = start.elapsed().unwrap().as_millis();
         times.push(time);
     }
 
+    assert_eq!(primes(10_000_000).len(), 664_579);
+
     let average = times.iter().sum::<u128>() / times.len() as u128;
     println!("Took {}ms on average", average);
 }
@@ -21,22 +24,16 @@ fn primes(max: usize) -> Vec<usize> {
 
     primes_list.push(2);
 
-
     for i in 3..max { //go through all numbers
-        let mut is_prime = true;
         for prime in &primes_list { //test each number
             if *prime > (i as f64).sqrt() as usize {
+                primes_list.push(i);
                 break;
             }
             if i % prime == 0 { //i = test number, j = some known prime
-                is_prime = false;
                 break;
             }
         }
-
-        if is_prime {
-            primes_list.push(i);
-        }
     }
 
     return primes_list;