Add Null move support to MovePicker.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 359c99c66aba1df979d60c47f4436f02db076a58..704cf720008d76e300b512ad378c99a14c0900ca 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -190,9 +190,6 @@ namespace {
   // Remaining depth:                 1 ply         1.5 ply       2 ply         2.5 ply       3 ply         3.5 ply
   const Value RazorApprMargins[6] = { Value(0x520), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) };
 
-  // The main transposition table
-  TranspositionTable TT;
-
 
   /// Variables initialized by UCI options
 
@@ -894,7 +891,7 @@ namespace {
         // Decide search depth for this move
         bool moveIsCapture = pos.move_is_capture(move);
         bool dangerous;
-        ext = extension(pos, move, true, pos.move_is_capture(move), pos.move_is_check(move), false, false, &dangerous);
+        ext = extension(pos, move, true, moveIsCapture, pos.move_is_check(move), false, false, &dangerous);
         newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
 
         // Make the move, and search it
@@ -918,8 +915,8 @@ namespace {
         }
         else
         {
-            if (newDepth >= 3*OnePly
-                && i + MultiPV >= LMRPVMoves
+            if (   newDepth >= 3*OnePly
+                && i >= MultiPV + LMRPVMoves - 2 // Remove -2 and decrease LMRPVMoves instead ?
                 && !dangerous
                 && !moveIsCapture
                 && !move_is_promotion(move)
@@ -927,10 +924,10 @@ namespace {
             {
                 ss[0].reduction = OnePly;
                 value = -search(pos, ss, -alpha, newDepth-OnePly, 1, true, 0);
-            }
-            else
+            } else
                 value = alpha + 1; // Just to trigger next condition
-            if(value > alpha)
+
+            if (value > alpha)
             {
                 value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
                 if (value > alpha)
@@ -1284,13 +1281,15 @@ 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 (    allowNullmove
-        &&  depth > OnePly
-        && !isCheck
-        && !value_is_mate(beta)
-        &&  ok_to_do_nullmove(pos)
-        &&  approximateEval >= beta - NullMoveMargin)
+    if (useNullMove)
     {
         ss[ply].currentMove = MOVE_NULL;
 
@@ -1329,12 +1328,13 @@ namespace {
         }
     }
     // Null move search not allowed, try razoring
-    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()))
+    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()))
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
         if (v < beta - RazorMargins[int(depth) - 2])
@@ -2270,12 +2270,13 @@ namespace {
 
     if (pos.type_of_piece_on(move_from(m)) == PAWN)
     {
-        if (pos.move_is_pawn_push_to_7th(m))
+        Color c = pos.side_to_move();
+        if (relative_rank(c, move_to(m)) == RANK_7)
         {
             result += PawnPushTo7thExtension[pvNode];
             *dangerous = true;
         }
-        if (pos.move_is_passed_pawn_push(m))
+        if (pos.pawn_is_passed(c, move_to(m)))
         {
             result += PassedPawnExtension[pvNode];
             *dangerous = true;