Tune search parameters (with Unai Corzo)

Vizvezdenec · MichaelB7 · commit 6a04c9215e0a · 2021-04-12T22:50:32.000-04:00
The values used in this patch are taken from a SPSA parameter tuning session originated by Unai Corzo (@unaiic), but the final difference of his tune was multiplied x2 by hand. Most of the credits should go to him :-) STC: https://tests.stockfishchess.org/tests/view/602f03d07f517a561bc49d40 LLR: 2.94 (-2.94,2.94) {-0.25,1.25} Total: 67664 W: 6252 L: 6035 D: 55377 Ptnml(0-2): 256, 4799, 23527, 4972, 278 LTC: https://tests.stockfishchess.org/tests/view/602f41697f517a561bc49d5a LLR: 2.96 (-2.94,2.94) {0.25,1.25} Total: 26256 W: 1034 L: 906 D: 24316 Ptnml(0-2): 10, 804, 11377, 922, 15 Closes official-stockfish#3363 Bench: 3957653
diff --git a/src/search.cpp b/src/search.cpp
@@ -1211,7 +1211,7 @@ namespace {
         && depth > 5
 #endif
         && (ss-1)->currentMove != MOVE_NULL
-        && (ss-1)->statScore < 22661
+        && (ss-1)->statScore < 24185
         &&  eval >= beta
         &&  eval >= ss->staticEval
         &&  ss->staticEval >= beta - 24 * depth - 34 * improving + 162 * ss->ttPv + 159
@@ -1490,7 +1490,7 @@ namespace {
                   &&  (*contHist[0])[movedPiece][to_sq(move)]
                     + (*contHist[1])[movedPiece][to_sq(move)]
                     + (*contHist[3])[movedPiece][to_sq(move)]
-                    + (*contHist[5])[movedPiece][to_sq(move)] / 3 < 26237)
+                    + (*contHist[5])[movedPiece][to_sq(move)] / 3 < 28255)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)
@@ -1618,7 +1618,7 @@ namespace {
               || moveCountPruning
               || ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha
               || cutNode
-              || (!PvNode && !formerPv && captureHistory[movedPiece][to_sq(move)][type_of(pos.captured_piece())] < 4506)
+              || (!PvNode && !formerPv && captureHistory[movedPiece][to_sq(move)][type_of(pos.captured_piece())] < 3678)
               || thisThread->ttHitAverage < 432 * TtHitAverageResolution * TtHitAverageWindow / 1024))
       {
           Depth r = reduction(improving, depth, moveCount);
@@ -1689,7 +1689,7 @@ namespace {
                              + (*contHist[0])[movedPiece][to_sq(move)]
                              + (*contHist[1])[movedPiece][to_sq(move)]
                              + (*contHist[3])[movedPiece][to_sq(move)]
-                             - 5337;
+                             - 4741;
 
               // Decrease/increase reduction by comparing opponent's stat score (~10 Elo)
               if (ss->statScore >= -89 && (ss-1)->statScore < -116)
@@ -1703,9 +1703,9 @@ namespace {
               // the sum of main history and first continuation history with an offset.
               if (ss->inCheck)
                   r -= (thisThread->mainHistory[us][from_to(move)]
-                     + (*contHist[0])[movedPiece][to_sq(move)] - 4341) / 16384;
+                     + (*contHist[0])[movedPiece][to_sq(move)] - 3833) / 16384;
               else
-                  r -= ss->statScore / 14382;
+                  r -= ss->statScore / 14790;
           }
 
           // In general we want to cap the LMR depth search at newDepth. But for nodes
