From 2e63c74ac67eb63fc571df10189d926215c96ed3 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Tue, 12 Dec 2023 18:26:04 +0000 Subject: [PATCH] Inline point count divide --- lightning/src/routing/scoring.rs | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/lightning/src/routing/scoring.rs b/lightning/src/routing/scoring.rs index 7c733c667..3493dea86 100644 --- a/lightning/src/routing/scoring.rs +++ b/lightning/src/routing/scoring.rs @@ -1173,10 +1173,10 @@ fn success_probability( /// min_zero_implies_no_successes signals that a `min_liquidity_msat` of 0 means we've not /// (recently) seen an HTLC successfully complete over this channel. #[inline(always)] -fn success_probability_times_value( +fn success_probability_times_value_times_billion( amount_msat: u64, min_liquidity_msat: u64, max_liquidity_msat: u64, capacity_msat: u64, params: &ProbabilisticScoringFeeParameters, min_zero_implies_no_successes: bool, - value: u32, + value_numerator: u64, value_denominator: u64, ) -> u64 { debug_assert!(min_liquidity_msat <= amount_msat); debug_assert!(amount_msat < max_liquidity_msat); @@ -1186,13 +1186,16 @@ fn success_probability_times_value( let (numerator, denominator) = linear_success_probability( amount_msat, min_liquidity_msat, max_liquidity_msat, min_zero_implies_no_successes ); - return (value as u64) * numerator / denominator; + const BILLIONISH: u64 = 1024 * 1024 * 1024; + return (value_numerator * BILLIONISH / value_denominator) * numerator / denominator; } let (num, mut den) = nonlinear_success_probability( amount_msat, min_liquidity_msat, max_liquidity_msat, capacity_msat ); + let value = (value_numerator as f64) / (value_denominator as f64); + if min_zero_implies_no_successes && min_liquidity_msat == 0 { // If we have no knowledge of the channel, scale probability down by ~75% // Note that we prefer to increase the denominator rather than decrease the numerator as @@ -1201,7 +1204,8 @@ fn success_probability_times_value( den = den * 21.0 / 16.0 } - let res = (value as f64) * num / den; + const BILLIONISH: f64 = 1024.0 * 1024.0 * 1024.0; + let res = (value * num / den) * BILLIONISH; res as u64 } @@ -1892,13 +1896,11 @@ mod bucketed_history { } let max_bucket_end_pos = BUCKET_START_POS[32 - highest_max_bucket_with_points] - 1; if payment_pos < max_bucket_end_pos { - let bucket_prob_times_billion = - (min_liquidity_offset_history_buckets[0] as u64) * total_max_points - * 1024 * 1024 * 1024 / total_valid_points_tracked; - debug_assert!(bucket_prob_times_billion < u32::max_value() as u64); - cumulative_success_prob_times_billion += success_probability_times_value( + let bucket_points = (min_liquidity_offset_history_buckets[0] as u64) * total_max_points; + cumulative_success_prob_times_billion += success_probability_times_value_times_billion( payment_pos as u64, 0, max_bucket_end_pos as u64, - POSITION_TICKS as u64 - 1, params, true, bucket_prob_times_billion as u32 + POSITION_TICKS as u64 - 1, params, true, + bucket_points, total_valid_points_tracked ); } } @@ -1928,13 +1930,11 @@ mod bucketed_history { } // Note that this multiply can only barely not overflow - two 16 bit ints plus // 30 bits is 62 bits. - let bucket_prob_times_billion = ((*min_bucket as u32) * (*max_bucket as u32)) as u64 - * 1024 * 1024 * 1024 / total_valid_points_tracked; - debug_assert!(bucket_prob_times_billion < u32::max_value() as u64); - cumulative_success_prob_times_billion += success_probability_times_value( + let bucket_points = ((*min_bucket as u32) * (*max_bucket as u32)) as u64; + cumulative_success_prob_times_billion += success_probability_times_value_times_billion( payment_pos as u64, min_bucket_start_pos as u64, max_bucket_end_pos as u64, POSITION_TICKS as u64 - 1, params, true, - bucket_prob_times_billion as u32); + bucket_points, total_valid_points_tracked); } } } -- 2.39.5