Don't compensate TT for evaluation drift

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 704cf720008d76e300b512ad378c99a14c0900ca..ac4d85b69996eb7abadda3cf61fcd9d50ec39cf7 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -916,7 +916,7 @@ namespace {
         else
         {
             if (   newDepth >= 3*OnePly
-                && i >= MultiPV + LMRPVMoves - 2 // Remove -2 and decrease LMRPVMoves instead ?
+                && i >= MultiPV + LMRPVMoves
                 && !dangerous
                 && !moveIsCapture
                 && !move_is_promotion(move)
@@ -1091,16 +1091,16 @@ namespace {
 
     // Initialize a MovePicker object for the current position, and prepare
     // to search all moves
-    MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
-
     Move move, movesSearched[256];
     int moveCount = 0;
     Value value, bestValue = -VALUE_INFINITE;
-    Bitboard dcCandidates = mp.discovered_check_candidates();
     Color us = pos.side_to_move();
     bool isCheck = pos.is_check();
     bool mateThreat = pos.has_mate_threat(opposite_color(us));
 
+    MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
+    Bitboard dcCandidates = mp.discovered_check_candidates();
+
     // Loop through all legal moves until no moves remain or a beta cutoff
     // occurs.
     while (   alpha < beta
@@ -1109,7 +1109,7 @@ namespace {
     {
       assert(move_is_ok(move));
 
-      bool singleReply = (isCheck && mp.number_of_moves() == 1);
+      bool singleReply = (isCheck && mp.number_of_evasions() == 1);
       bool moveIsCheck = pos.move_is_check(move, dcCandidates);
       bool moveIsCapture = pos.move_is_capture(move);
 
@@ -1281,15 +1281,13 @@ namespace {
     bool mateThreat = false;
     bool isCheck = pos.is_check();
 
-    bool useNullMove = (    allowNullmove
-                        &&  depth > OnePly
-                        && !isCheck
-                        && !value_is_mate(beta)
-                        &&  ok_to_do_nullmove(pos)
-                        &&  approximateEval >= beta - NullMoveMargin);
-
     // Null move search
-    if (useNullMove)
+    if (    allowNullmove
+        &&  depth > OnePly
+        && !isCheck
+        && !value_is_mate(beta)
+        &&  ok_to_do_nullmove(pos)
+        &&  approximateEval >= beta - NullMoveMargin)
     {
         ss[ply].currentMove = MOVE_NULL;
 
@@ -1328,13 +1326,12 @@ namespace {
         }
     }
     // Null move search not allowed, try razoring
-    if (    !useNullMove
-         && !value_is_mate(beta)
-         && depth < RazorDepth
-         && approximateEval < beta - RazorApprMargins[int(depth) - 2]
-         && ss[ply - 1].currentMove != MOVE_NULL
-         && ttMove == MOVE_NONE
-         && !pos.has_pawn_on_7th(pos.side_to_move()))
+    else if (   !value_is_mate(beta)
+             && depth < RazorDepth
+             && approximateEval < beta - RazorApprMargins[int(depth) - 2]
+             && ss[ply - 1].currentMove != MOVE_NULL
+             && ttMove == MOVE_NONE
+             && !pos.has_pawn_on_7th(pos.side_to_move()))
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
         if (v < beta - RazorMargins[int(depth) - 2])
@@ -1369,7 +1366,7 @@ namespace {
     {
       assert(move_is_ok(move));
 
-      bool singleReply = (isCheck && mp.number_of_moves() == 1);
+      bool singleReply = (isCheck && mp.number_of_evasions() == 1);
       bool moveIsCheck = pos.move_is_check(move, dcCandidates);
       bool moveIsCapture = pos.move_is_capture(move);
 
@@ -1543,10 +1540,10 @@ namespace {
         // Use the cached evaluation score if possible
         assert(ei.futilityMargin == Value(0));
 
-        staticValue = tte->value();
+        staticValue = tte->value() + ply;
     }
     else
-        staticValue = evaluate(pos, ei, threadID);
+        staticValue = evaluate(pos, ei, threadID) + ply;
 
     if (ply == PLY_MAX - 1)
         return evaluate(pos, ei, threadID);
@@ -1965,15 +1962,15 @@ namespace {
     bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
 
     // Generate all legal moves
-    int lm_count = generate_legal_moves(pos, mlist);
+    MoveStack* last = generate_legal_moves(pos, mlist);
 
     // Add each move to the moves[] array
-    for (int i = 0; i < lm_count; i++)
+    for (MoveStack* cur = mlist; cur != last; cur++)
     {
         bool includeMove = includeAllMoves;
 
         for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++)
-            includeMove = (searchMoves[k] == mlist[i].move);
+            includeMove = (searchMoves[k] == cur->move);
 
         if (!includeMove)
             continue;
@@ -1982,7 +1979,7 @@ namespace {
         StateInfo st;
         SearchStack ss[PLY_MAX_PLUS_2];
 
-        moves[count].move = mlist[i].move;
+        moves[count].move = cur->move;
         pos.do_move(moves[count].move, st);
         moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
         pos.undo_move(moves[count].move);
@@ -2188,7 +2185,7 @@ namespace {
     // Case 5: Discovered check, checking piece is the piece moved in m1
     if (   piece_is_slider(pos.piece_on(t1))
         && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
-        && !bit_is_set(squares_between(t2, pos.king_square(pos.side_to_move())), t2))
+        && !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2))
     {
         Bitboard occ = pos.occupied_squares();
         Color us = pos.side_to_move();