f - divide by a power of 2

jkczyz · jkczyz · commit 9a855be4f898 · 2023-07-10T14:11:37.000-05:00
diff --git a/lightning/src/routing/scoring.rs b/lightning/src/routing/scoring.rs
@@ -1165,8 +1165,9 @@ impl<L: Deref<Target = u64>, BRT: Deref<Target = HistoricalBucketRangeTracker>,
 			if half_decays % 2 == 0 {
 				decayed_offset_msat
 			} else {
-				// 71 / 100 ~= core::f64::consts::FRAC_1_SQRT_2
-				(decayed_offset_msat as u128 * 71 / 100) as u64
+				// 11_585 / 16_384 ~= core::f64::consts::FRAC_1_SQRT_2
+				// 16_384 == 2^14
+				(decayed_offset_msat as u128 * 11_585 / 16_384) as u64
 			}
 		}
 	}

Original file line number	Diff line number	Diff line change
`@@ -1165,8 +1165,9 @@ impl<L: Deref<Target = u64>, BRT: Deref<Target = HistoricalBucketRangeTracker>,`
`1165`	`1165`	`if half_decays % 2 == 0 {`
`1166`	`1166`	`decayed_offset_msat`
`1167`	`1167`	`} else {`
`1168`		`- // 71 / 100 ~= core::f64::consts::FRAC_1_SQRT_2`
`1169`		`- (decayed_offset_msat as u128 * 71 / 100) as u64`
	`1168`	`+ // 11_585 / 16_384 ~= core::f64::consts::FRAC_1_SQRT_2`
	`1169`	`+ // 16_384 == 2^14`
	`1170`	`+ (decayed_offset_msat as u128 * 11_585 / 16_384) as u64`
`1170`	`1171`	`}`
`1171`	`1172`	`}`
`1172`	`1173`	`}`