Add search noise as UCI option

Tearth · Nov 23, 2024 · 072c98a · 072c98a
1 parent 8187cd9
commit 072c98a
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Showing 3 changed files with 11 additions and 1 deletion.
diff --git a/src/engine/context.rs b/src/engine/context.rs
@@ -38,6 +38,7 @@ pub struct SearchContext {
     pub uci_debug: bool,
     pub ponder_mode: bool,
     pub soft_nodes: bool,
+    pub search_noise: bool,
     pub syzygy_enabled: bool,
     pub syzygy_probe_limit: u32,
     pub syzygy_probe_depth: i8,
@@ -91,6 +92,7 @@ impl SearchContext {
             uci_debug: false,
             ponder_mode: false,
             soft_nodes: false,
+            search_noise: false,
             syzygy_enabled: false,
             syzygy_probe_limit: 0,
             syzygy_probe_depth: 0,

diff --git a/src/engine/search/movepick.rs b/src/engine/search/movepick.rs
@@ -6,6 +6,7 @@ use crate::utils::assert_fast;
 use crate::utils::bithelpers::BitHelpers;
 use crate::utils::dev;
 use crate::utils::panic_fast;
+use crate::utils::rand;
 use crate::MoveScores;
 use crate::Moves;
 use std::mem::MaybeUninit;
@@ -332,7 +333,11 @@ fn assign_quiet_scores(context: &SearchContext, state: &mut MoveGenState, start_
                 continue;
             }
 
-            let value = context.htable.get(r#move.get_from(), r#move.get_to(), MOVEORD_HISTORY_MOVE) as i16;
+            let mut value = context.htable.get(r#move.get_from(), r#move.get_to(), MOVEORD_HISTORY_MOVE) as i16;
+            if context.search_noise {
+                value = i16::clamp(value + rand::i16(-5..5), 0, MOVEORD_HISTORY_MOVE as i16);
+            }
+
             state.move_scores[move_index].write(value + MOVEORD_HISTORY_MOVE_OFFSET);
         } else if r#move.is_promotion() {
             state.move_scores[move_index].write(match r#move.get_promotion_piece() {

diff --git a/src/interface/uci.rs b/src/interface/uci.rs
@@ -117,6 +117,7 @@ pub fn run() {
     #[cfg(feature = "dev")]
     {
         options_lock.insert("Soft Nodes".to_string(), UciOption::new(50, "check", false, false, false));
+        options_lock.insert("Search Noise".to_string(), UciOption::new(50, "check", false, false, false));
         options_lock.insert("Crash Files".to_string(), UciOption::new(50, "check", false, false, false));
     }
 
@@ -388,6 +389,7 @@ fn handle_go(params: &[String], state: &UciState) {
         let syzygy_probe_limit = options_lock["SyzygyProbeLimit"].value.parse::<u32>().unwrap();
         let syzygy_probe_depth = options_lock["SyzygyProbeDepth"].value.parse::<i8>().unwrap();
         let soft_nodes = options_lock["Soft Nodes"].value.parse::<bool>().unwrap();
+        let search_noise = options_lock["Search Noise"].value.parse::<bool>().unwrap();
 
         #[cfg(not(feature = "dev"))]
         let search_params = SearchParams::default();
@@ -456,6 +458,7 @@ fn handle_go(params: &[String], state: &UciState) {
         context_lock.uci_debug = debug_mode;
         context_lock.ponder_mode = ponder_mode;
         context_lock.soft_nodes = soft_nodes;
+        context_lock.search_noise = search_noise;
         context_lock.syzygy_enabled = syzygy_enabled;
         context_lock.syzygy_probe_limit = syzygy_probe_limit;
         context_lock.syzygy_probe_depth = syzygy_probe_depth;