Reintroduce Contempt

Bench 2771721 Attempt something similar to XintheDark contempt_reintro1a contempt_reintro1b @cj5716 cj5716 committed
Zerbinati · Jun 23, 2023 · bfcc0ea · bfcc0ea
1 parent 1a41bed
commit bfcc0ea
Show file tree

Hide file tree

Showing 4 changed files with 9 additions and 3 deletions.
diff --git a/src/evaluate.cpp b/src/evaluate.cpp
@@ -1070,12 +1070,15 @@ Value Eval::evaluate(const Position& pos) {
 
       Color stm = pos.side_to_move();
       Value optimism = pos.this_thread()->optimism[stm];
+      Value contempt = stm == WHITE ? -pos.this_thread()->contempt : pos.this_thread()->contempt;
+
 
       Value nnue = NNUE::evaluate(pos, true, &nnueComplexity);
 
       // Blend optimism with nnue complexity and (semi)classical complexity
       optimism += optimism * (nnueComplexity + abs(psq - nnue)) / 512;
       v = (nnue * (945 + npm) + optimism * (150 + npm)) / 1024;
+      v += v * (stm == WHITE ? 1 : -1) >= 0 ? contempt : 0;
   }
 
   // Damp down the evaluation linearly when shuffling

diff --git a/src/search.cpp b/src/search.cpp
@@ -480,6 +480,7 @@ void Thread::search() {
 
   multiPV = std::min(multiPV, rootMoves.size());
 
+  int ct = Options["Contempt"] * PawnValueEg / 100;
   int searchAgainCounter = 0;
 
   // Iterative deepening loop until requested to stop or the target depth is reached
@@ -522,6 +523,9 @@ void Thread::search() {
           alpha = std::max(prev - delta,-VALUE_INFINITE);
           beta  = std::min(prev + delta, VALUE_INFINITE);
 
+          // Adjust contempt based on root move's previousScore
+          contempt = Value(ct) + 88 * prev / (std::abs(prev) + 200);
+
           // Adjust optimism based on root move's previousScore
           int opt = 109 * prev / (std::abs(prev) + 141);
           optimism[ us] = Value(opt);

diff --git a/src/thread.h b/src/thread.h
@@ -62,7 +62,7 @@ class Thread {
   size_t pvIdx, pvLast;
   std::atomic<uint64_t> nodes, tbHits, bestMoveChanges;
   int selDepth, nmpMinPly;
-  Value bestValue, optimism[COLOR_NB];
+  Value bestValue, optimism[COLOR_NB], contempt;
 
   Position rootPos;
   StateInfo rootState;

diff --git a/src/ucioption.cpp b/src/ucioption.cpp
@@ -48,8 +48,6 @@ static void on_book1(const Option& o) { Book::on_book(0, (string)o); }
 static void on_book2(const Option& o) { Book::on_book(1, (string)o); }
 static void on_book3(const Option& o) { Book::on_book(2, (string)o); }
 static void on_tb_path(const Option& o) { Tablebases::init(o); }
-static void on_predicted_S(const Option&) { Search::init(); }
-static void on_predicted_F(const Option&) { Search::init(); }
 static void on_exp_enabled(const Option& /*o*/) { Experience::init(); }
 static void on_exp_file(const Option& /*o*/) { Experience::init(); }
 static void on_use_NNUE(const Option&) { Eval::NNUE::init(); }
@@ -78,6 +76,7 @@ void init(OptionsMap& o) {
   o["Ponder"]                              << Option(false);
   o["MultiPV"]                             << Option(1, 1, 500);
   o["Skill Level"]                         << Option(20, 0, 20);
+  o["Contempt"]                            << Option(20, -100, 100);
   o["Move Overhead"]                       << Option(10, 0, 5000);
   o["Minimum Thinking Time"]               << Option(100, 0, 5000);
   o["Slow Mover"]                          << Option(100, 10, 1000);