From 2f7a449038fb5dbc620e9f156c24bb6fa318d8fb Mon Sep 17 00:00:00 2001 From: eug-vs Date: Mon, 4 Sep 2023 10:23:56 +0300 Subject: feat: define strict ordering between ttable items --- src/grossmeister/ttable.rs | 59 ++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 52 insertions(+), 7 deletions(-) (limited to 'src/grossmeister/ttable.rs') diff --git a/src/grossmeister/ttable.rs b/src/grossmeister/ttable.rs index 87099c2..0420e22 100644 --- a/src/grossmeister/ttable.rs +++ b/src/grossmeister/ttable.rs @@ -1,3 +1,5 @@ +use std::cmp::Ordering; + use crate::moves::Move; use super::Grossmeister; @@ -13,6 +15,21 @@ pub enum NodeType { All, } +impl NodeType { + fn cmp_order(&self) -> u8 { + match self { + NodeType::PV => 2, + NodeType::Cut => 1, + NodeType::All => 0, + } + } +} +impl PartialOrd for NodeType { + fn partial_cmp(&self, other: &Self) -> Option { + Some(self.cmp_order().cmp(&other.cmp_order())) + } +} + #[derive(Debug, PartialEq, Clone, Copy)] pub struct TranspositionTableItem { /// Zobrist hash of this position @@ -23,18 +40,34 @@ pub struct TranspositionTableItem { pub node_type: NodeType, } -pub const TTABLE_SIZE: u64 = 2u64.pow(24); +impl PartialOrd for TranspositionTableItem { + fn partial_cmp(&self, other: &Self) -> Option { + // Order by depth first, then node type + let depth_ordering = self.depth.partial_cmp(&other.depth); + match depth_ordering { + Some(Ordering::Equal) => self.node_type.partial_cmp(&other.node_type), + _ => depth_ordering, + } + } +} -pub type TranspositionTable = Vec>; +pub const TTABLE_SIZE: u64 = 2u64.pow(24); +pub type TranspositionTable = Vec>; impl Grossmeister { - /// Find current transposition in Transposition Table - pub fn transposition(&self) -> Option { - match self.transposition_table[(self.board.hash % TTABLE_SIZE) as usize] { + fn transposition_ref(&mut self) -> &mut Option { + &mut self.transposition_table[(self.board.hash % TTABLE_SIZE) as usize] + } + + /// Find current position in Transposition Table + /// This operation is safe from collisions since it compares the *full* hash + pub fn transposition(&mut self) -> Option { + let hash = self.board.hash; + match self.transposition_ref() { Some(item) => { - if item.hash == self.board.hash { - return Some(item) + if item.hash == hash { + return Some(*item) } None } @@ -42,4 +75,16 @@ impl Grossmeister { } } + pub fn store_transposition(&mut self, transposition: TranspositionTableItem) { + let transposition_ref = self.transposition_ref(); + match transposition_ref { + Some(existing_transposition) => { + if transposition >= *existing_transposition { + *transposition_ref = Some(transposition) + } + } + None => *transposition_ref = Some(transposition) + } + } + } -- cgit v1.2.3