Update UCI_Elo parameterization

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index f5eeb23b43f5c84cbfb81da457bc00726ac71027..346fd6c3a7ab322c0cdc4eb4f29397cd3b799a28 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -96,7 +96,10 @@ namespace {
   struct Skill {
     Skill(int skill_level, int uci_elo) {
         if (uci_elo)
-            level = std::clamp(std::pow((uci_elo - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0);
+        {
+            double e = double(uci_elo - 1320) / (3190 - 1320);
+            level = std::clamp((((37.2473 * e - 40.8525) * e + 22.2943) * e - 0.311438), 0.0, 19.0);
+        }
         else
             level = double(skill_level);
     }