Merge branch 'master' into WDLconversion

LeelaChessZero · May 21, 2023 · 1e00ff0 · 1e00ff0
2 parents f876733 + 905d88e
commit 1e00ff0
Showing 1 changed file with 11 additions and 13 deletions.
diff --git a/src/mcts/search.cc b/src/mcts/search.cc
@@ -106,9 +106,10 @@ class MEvaluator {
     }
   }
 
-  float GetM(const EdgeAndNode& child, float q) const {
+  // Calculates the utility for favoring shorter wins and longer losses.
+  float GetMUtility(Node* child, float q) const {
     if (!enabled_ || !parent_within_threshold_) return 0.0f;
-    const float child_m = child.GetM(parent_m_);
+    const float child_m = child->GetM();
     float m = std::clamp(m_slope_ * (child_m - parent_m_), -m_cap_, m_cap_);
     m *= FastSign(-q);
     if (q_threshold_ > 0.0f && q_threshold_ < 1.0f) {
@@ -120,17 +121,14 @@ class MEvaluator {
     return m;
   }
 
-  float GetM(Node* child, float q) const {
+  float GetMUtility(const EdgeAndNode& child, float q) const {
     if (!enabled_ || !parent_within_threshold_) return 0.0f;
-    const float child_m = child->GetM();
-    float m = std::clamp(m_slope_ * (child_m - parent_m_), -m_cap_, m_cap_);
-    m *= FastSign(-q);
-    m *= a_constant_ + a_linear_ * std::abs(q) + a_square_ * q * q;
-    return m;
+    if (child.GetN() == 0) return GetDefaultMUtility();
+    return GetMUtility(child.node(), q);
   }
 
   // The M utility to use for unvisited nodes.
-  float GetDefaultM() const { return 0.0f; }
+  float GetDefaultMUtility() const { return 0.0f; }
 
  private:
   static bool WithinThreshold(const Node* parent, float q_threshold) {
@@ -518,7 +516,7 @@ std::vector<std::string> Search::GetVerboseStats(Node* node) const {
                                : MEvaluator();
   for (const auto& edge : edges) {
     float Q = edge.GetQ(fpu, draw_score);
-    float M = m_evaluator.GetM(edge, Q);
+    float M = m_evaluator.GetMUtility(edge, Q);
     std::ostringstream oss;
     oss << std::left;
     // TODO: should this be displaying transformed index?
@@ -931,7 +929,7 @@ void Search::PopulateCommonIterationStats(IterationStats* stats) {
     for (const auto& edge : root_node_->Edges()) {
       const auto n = edge.GetN();
       const auto q = edge.GetQ(fpu, draw_score);
-      const auto m = m_evaluator.GetM(edge, q);
+      const auto m = m_evaluator.GetMUtility(edge, q);
       const auto q_plus_m = q + m;
       stats->edge_n.push_back(n);
       if (n > 0 && edge.IsTerminal() && edge.GetWL(0.0f) > 0.0f) {
@@ -1668,13 +1666,13 @@ void SearchWorker::PickNodesToExtendTask(
         int index = child->Index();
         visited_pol += current_pol[index];
         float q = child->GetQ(draw_score);
-        current_util[index] = q + m_evaluator.GetM(child, q);
+        current_util[index] = q + m_evaluator.GetMUtility(child, q);
       }
       const float fpu =
           GetFpu(params_, node, is_root_node, draw_score, visited_pol);
       for (int i = 0; i < max_needed; i++) {
         if (current_util[i] == std::numeric_limits<float>::lowest()) {
-          current_util[i] = fpu + m_evaluator.GetDefaultM();
+          current_util[i] = fpu + m_evaluator.GetDefaultMUtility();
         }
       }