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feat: skepticism

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garbage mitigation for the horizon problem
This commit is contained in:
dogeystamp 2024-11-23 21:17:20 -05:00
parent e8cb125df9
commit c494230706
1 changed files with 15 additions and 3 deletions
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18
src/search.rs
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@ -105,6 +105,7 @@ impl Default for SearchConfig {
fn default() -> Self { fn default() -> Self {
SearchConfig { SearchConfig {
alpha_beta_on: true, alpha_beta_on: true,
// try to make this even to be more conservative and avoid horizon problem
depth: 10, depth: 10,
} }
} }
@ -267,14 +268,24 @@ fn iter_deep(
interface: Option<InterfaceRx>, interface: Option<InterfaceRx>,
cache: &mut TranspositionTableOpt, cache: &mut TranspositionTableOpt,
) -> (Vec<Move>, SearchEval) { ) -> (Vec<Move>, SearchEval) {
for depth in 1..=config.depth { let (mut prev_line, mut prev_eval) = minmax(board, config, 1, None, None, cache);
for depth in 2..=config.depth {
let (line, eval) = minmax(board, config, depth, None, None, cache); let (line, eval) = minmax(board, config, depth, None, None, cache);
if let Some(ref rx) = interface { if let Some(ref rx) = interface {
// don't interrupt a depth 1 search so that there's at least a move to be played // don't interrupt a depth 1 search so that there's at least a move to be played
if depth != 1 { if depth != 1 {
match rx.try_recv() { match rx.try_recv() {
Ok(msg) => match msg { Ok(msg) => match msg {
InterfaceMsg::Stop => return (line, eval), InterfaceMsg::Stop => {
if depth & 1 == 0 && (EvalInt::from(eval) - EvalInt::from(prev_eval) > 300) {
// be skeptical if we move last and we suddenly earn a lot of
// centipawns. this may be a sign of horizon problem
return (line, eval)
} else {
return (prev_line, prev_eval)
}
},
}, },
Err(e) => match e { Err(e) => match e {
mpsc::TryRecvError::Empty => {} mpsc::TryRecvError::Empty => {}
@ -285,8 +296,9 @@ fn iter_deep(
} else if depth == config.depth - 1 { } else if depth == config.depth - 1 {
return (line, eval); return (line, eval);
} }
(prev_line, prev_eval) = (line, eval);
} }
panic!("iterative deepening did not search at all") (prev_line, prev_eval)
} }
/// Find the best line (in reverse order) and its evaluation. /// Find the best line (in reverse order) and its evaluation.