f handle zero half life

Author: TheBlueMatt

lightning/src/routing/scoring.rs

@@ -1509,14 +1509,16 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time> ScoreUpdate for Prob
 				T::now().duration_since(liquidity.offset_history_last_updated);
 			if elapsed_time > decay_params.historical_no_updates_half_life {
 				let half_life = decay_params.historical_no_updates_half_life.as_secs_f64();
-				let divisor = powf64(2048.0, elapsed_time.as_secs_f64() / half_life) as u64;
-				for bucket in liquidity.min_liquidity_offset_history.buckets.iter_mut() {
-					*bucket = ((*bucket as u64) * 1024 / divisor) as u16;
-				}
-				for bucket in liquidity.max_liquidity_offset_history.buckets.iter_mut() {
-					*bucket = ((*bucket as u64) * 1024 / divisor) as u16;
+				if half_life != 0.0 {
+					let divisor = powf64(2048.0, elapsed_time.as_secs_f64() / half_life) as u64;
+					for bucket in liquidity.min_liquidity_offset_history.buckets.iter_mut() {
+						*bucket = ((*bucket as u64) * 1024 / divisor) as u16;
+					}
+					for bucket in liquidity.max_liquidity_offset_history.buckets.iter_mut() {
+						*bucket = ((*bucket as u64) * 1024 / divisor) as u16;
+					}
+					liquidity.offset_history_last_updated = T::now();
 				}
-				liquidity.offset_history_last_updated = T::now();
 			}
 			liquidity.min_liquidity_offset_msat != 0 || liquidity.max_liquidity_offset_msat != 0 ||
 				liquidity.min_liquidity_offset_history.buckets != [0; 32] ||