adjust child utility when it has mate bound

test f15
dhbloo · Oct 15, 2024 · 54d1b61 · 54d1b61
1 parent 58ed3f3
commit 54d1b61
Showing 1 changed file with 10 additions and 1 deletion.
diff --git a/Rapfi/search/mcts/search.cpp b/Rapfi/search/mcts/search.cpp
@@ -355,7 +355,16 @@ std::pair<Edge *, Node *> selectChild(Node &node, const Board &board)
         uint32_t childVirtualVisits = childNode->getVirtualVisits();
         float    childUtility       = -childNode->getQ();
         float    childDraw          = childNode->getD();
-        float    selectionValue     = puctSelectionValue(childUtility,
+
+        ValueBound childBound = childNode->getBound();
+        // Do not select non-mate child when there is a mate child
+        if (childBound.childLowerBound() >= VALUE_MATED_IN_MAX_PLY)
+            childUtility += 1.0f;
+        // Do not select mated child when there is a non-mated child
+        if (childBound.childUpperBound() <= VALUE_MATED_IN_MAX_PLY)
+            childUtility -= 1.0f;
+
+        float selectionValue = puctSelectionValue(childUtility,
                                                   childDraw,
                                                   parentDraw,
                                                   childPolicy,