📦 NEW: Use scc map

Cargo.toml

@@ -11,11 +11,11 @@ path = "src/main.rs"
 [dependencies]
 arc-swap = "=1.6.0"
 arrayvec = "=0.7.4"
-dashmap = "=5.5.3"
 fastapprox = "=0.3.1"
 goober = { git = "https://github.com/jw1912/goober/", rev = "32b9b52" }
 nohash-hasher = "=0.2.0"
 memmap = "=0.7.0"
+scc = "=2.1.16"
 scoped_threadpool = "=0.1.9"
 
 [features]

src/arena.rs

@@ -90,7 +90,7 @@ impl Arena {
     }
 
     pub fn allocator(&self) -> Allocator {
-        let id = IDS.fetch_add(1, Ordering::SeqCst);
+        let id = IDS.fetch_add(1, Ordering::Relaxed);
 
         Allocator {
             id,

src/lib.rs

@@ -4,10 +4,10 @@
 
 extern crate arc_swap;
 extern crate arrayvec;
-extern crate dashmap;
 extern crate fastapprox;
 extern crate memmap;
 extern crate nohash_hasher;
+extern crate scc;
 
 mod arena;
 mod mem;

src/search_tree.rs

@@ -105,7 +105,7 @@ impl PositionNode {
         let hots = unsafe { &*(self.hots.cast_mut()) };
 
         for h in hots {
-            h.child.store(null_mut(), Ordering::SeqCst);
+            h.child.store(null_mut(), Ordering::Relaxed);
         }
     }
 
@@ -432,16 +432,14 @@ impl SearchTree {
             self.search_options.mcts_options.policy_temperature,
         )?;
 
+        // Copy any history
         self.ttable.lookup_into(state, &mut created_here);
 
+        // Copy node to arena memory
         let created = tld.allocator.alloc_node()?;
-
         *created = created_here;
 
-        if let Some(node) = choice.set_or_get_child(created) {
-            return Ok(node);
-        }
-
+        // Insert the child into the ttable
         let inserted = self.ttable.insert(state, created);
         let inserted_ptr = ptr::from_ref(inserted).cast_mut();
         choice.child.store(inserted_ptr, Ordering::Relaxed);