Might not be a good idea, but testing this.

src/lib.rs

@@ -1,11 +1,14 @@
+#[inline(always)]
 pub fn rating(a: f32, b: f32, score: f32, n: f32, k: f32) -> f32 {
     a + delta(score, expected(a, b, n), k)
 }
 
+#[inline(always)]
 fn delta(score: f32, rating: f32, k: f32) -> f32 {
     k * (score - rating)
 }
 
+#[inline(always)]
 fn expected(a: f32, b: f32, n: f32) -> f32 {
     1.0 / (1.0 + 10.0_f32.powf((b - a) / n))
 }