f clearer math

Author: TheBlueMatt

lightning/src/routing/scoring.rs

@@ -1057,7 +1057,7 @@ fn success_probability(
 			let num = max_pow - (amount - 0.5).powi(3);
 			let den = max_pow - (min - 0.5).powi(3);
 
-			// Because our numerator and denominator max out at 2^-3 we need to multiply them by
+			// Because our numerator and denominator max out at 0.5^3 we need to multiply them by
 			// quite a large factor to get something useful (ideally in the 2^30 range).
 			const BILLIONISH: f64 = 1024.0 * 1024.0 * 1024.0;
 			let numerator = (num * BILLIONISH) as u64 + 1;