From: Unai Corzo <corzounai@gmail.com>
Date: Wed, 30 Dec 2020 14:38:25 +0000 (+0100)
Subject: Assorted parameter tweak
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=c57c71bf5c56665b0339fa983665bdef4bf8a099

Assorted parameter tweak

Parameter tweak from various tunes and patches.

STC https://tests.stockfishchess.org/tests/view/5fec2ae36019e097de3ee94a
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 41976 W: 4032 L: 3848 D: 34096
Ptnml(0-2): 147, 3086, 14341, 3264, 150

LTC https://tests.stockfishchess.org/tests/view/5fec5c3c6019e097de3ee973
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 23936 W: 970 L: 844 D: 22122
Ptnml(0-2): 14, 749, 10319, 869, 17

closes https://github.com/official-stockfish/Stockfish/pull/3281

bench: 4354546
---

diff --git a/src/movepick.h b/src/movepick.h
index 4c0ad551..f8472c6e 100644
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -84,7 +84,7 @@ enum StatsType { NoCaptures, Captures };
 /// unsuccessful during the current search, and is used for reduction and move
 /// ordering decisions. It uses 2 tables (one for each color) indexed by
 /// the move's from and to squares, see www.chessprogramming.org/Butterfly_Boards
-typedef Stats<int16_t, 10692, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyHistory;
+typedef Stats<int16_t, 13365, COLOR_NB, int(SQUARE_NB) * int(SQUARE_NB)> ButterflyHistory;
 
 /// At higher depths LowPlyHistory records successful quiet moves near the root
 /// and quiet moves which are/were in the PV (ttPv). It is cleared with each new
diff --git a/src/search.cpp b/src/search.cpp
index c6db82ba..5f545ef6 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -82,7 +82,7 @@ namespace {
 
   // History and stats update bonus, based on depth
   int stat_bonus(Depth d) {
-    return d > 13 ? 29 : 17 * d * d + 134 * d - 134;
+    return d > 14 ? 29 : 8 * d * d + 224 * d - 215;
   }
 
   // Add a small random component to draw evaluations to avoid 3fold-blindness
@@ -838,7 +838,7 @@ namespace {
 
     // Step 8. Futility pruning: child node (~50 Elo)
     if (   !PvNode
-        &&  depth < 8
+        &&  depth < 9
         &&  eval - futility_margin(depth, improving) >= beta
         &&  eval < VALUE_KNOWN_WIN) // Do not return unproven wins
         return eval;
@@ -893,7 +893,7 @@ namespace {
         }
     }
 
-    probCutBeta = beta + 183 - 49 * improving;
+    probCutBeta = beta + 194 - 49 * improving;
 
     // Step 10. ProbCut (~10 Elo)
     // If we have a good enough capture and a reduced search returns a value
@@ -1058,11 +1058,11 @@ moves_loop: // When in check, search starts from here
               // Futility pruning: parent node (~5 Elo)
               if (   lmrDepth < 7
                   && !ss->inCheck
-                  && ss->staticEval + 266 + 170 * lmrDepth <= alpha
+                  && ss->staticEval + 254 + 159 * lmrDepth <= alpha
                   &&  (*contHist[0])[movedPiece][to_sq(move)]
                     + (*contHist[1])[movedPiece][to_sq(move)]
                     + (*contHist[3])[movedPiece][to_sq(move)]
-                    + (*contHist[5])[movedPiece][to_sq(move)] / 2 < 27376)
+                    + (*contHist[5])[movedPiece][to_sq(move)] / 2 < 26394)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)
@@ -1078,7 +1078,7 @@ moves_loop: // When in check, search starts from here
                   continue;
 
               // SEE based pruning
-              if (!pos.see_ge(move, Value(-213) * depth)) // (~25 Elo)
+              if (!pos.see_ge(move, Value(-218) * depth)) // (~25 Elo)
                   continue;
           }
       }