Offset pv[] always from 0

We don't need to offset from current ply.

Also rewritten a bit update_pv()

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/search.cpp b/src/search.cpp
index 5a12ec7e672419aca09d0ec78d742eaa3d8d8c28..65395b4ec95943171b5bafddde76d4bf0e41c0bb 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -296,8 +296,8 @@ namespace {
   template <NodeType PvNode>
   Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous);
 
-  void update_pv(SearchStack* ss, int ply);
-  void sp_update_pv(SearchStack* pss, SearchStack* ss, int ply);
+  void update_pv(SearchStack* ss);
+  void sp_update_pv(SearchStack* pss, SearchStack* ss);
   bool connected_moves(const Position& pos, Move m1, Move m2);
   bool value_is_mate(Value value);
   bool move_is_killer(Move m, SearchStack* ss);
@@ -366,9 +366,9 @@ void init_search() {
 
 // SearchStack::init() initializes a search stack. Used at the beginning of a
 // new search from the root.
-void SearchStack::init(int ply) {
+void SearchStack::init() {
 
-  pv[ply] = pv[ply + 1] = MOVE_NONE;
+  pv[0] = pv[1] = MOVE_NONE;
   currentMove = threatMove = MOVE_NONE;
   reduction = Depth(0);
   eval = VALUE_NONE;
@@ -936,7 +936,7 @@ namespace {
                 // We are failing high and going to do a research. It's important to update
                 // the score before research in case we run out of time while researching.
                 rml.set_move_score(i, value);
-                update_pv(ss, 0);
+                update_pv(ss);
                 TT.extract_pv(pos, ss->pv, PLY_MAX);
                 rml.set_move_pv(i, ss->pv);
 
@@ -976,7 +976,7 @@ namespace {
 
                 // Update PV
                 rml.set_move_score(i, value);
-                update_pv(ss, 0);
+                update_pv(ss);
                 TT.extract_pv(pos, ss->pv, PLY_MAX);
                 rml.set_move_pv(i, ss->pv);
 
@@ -1072,8 +1072,8 @@ namespace {
 
     // Step 1. Initialize node and poll. Polling can abort search
     TM.incrementNodeCounter(threadID);
-    ss->init(ply);
-    (ss + 2)->initKillers();
+    ss->init();
+    (ss+2)->initKillers();
 
     if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
     {
@@ -1244,7 +1244,7 @@ namespace {
         search<PvNode>(pos, ss, alpha, beta, d);
         ss->skipNullMove = false;
 
-        ttMove = ss->pv[ply];
+        ttMove = ss->pv[0];
         tte = TT.retrieve(posKey);
     }
 
@@ -1409,7 +1409,7 @@ namespace {
               if (PvNode && value < beta) // This guarantees that always: alpha < beta
                   alpha = value;
 
-              update_pv(ss, ply);
+              update_pv(ss);
 
               if (value == value_mate_in(ply + 1))
                   ss->mateKiller = move;
@@ -1447,7 +1447,7 @@ namespace {
     else if (bestValue >= beta)
     {
         TM.incrementBetaCounter(pos.side_to_move(), depth, threadID);
-        move = ss->pv[ply];
+        move = ss->pv[0];
         TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
         if (!pos.move_is_capture_or_promotion(move))
         {
@@ -1456,7 +1456,7 @@ namespace {
         }
     }
     else
-        TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss->pv[ply], ss->eval, ei.kingDanger[pos.side_to_move()]);
+        TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss->pv[0], ss->eval, ei.kingDanger[pos.side_to_move()]);
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
@@ -1488,7 +1488,7 @@ namespace {
     int ply = pos.ply();
 
     TM.incrementNodeCounter(pos.thread());
-    ss->pv[ply] = ss->pv[ply + 1] = ss->currentMove = MOVE_NONE;
+    ss->pv[0] = ss->pv[1] = ss->currentMove = MOVE_NONE;
     ss->eval = VALUE_NONE;
 
     // Check for an instant draw or maximum ply reached
@@ -1532,7 +1532,7 @@ namespace {
         {
             if (!tte) // FIXME, remove condition
                 TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
-           
+
             return bestValue;
         }
 
@@ -1615,7 +1615,7 @@ namespace {
           if (value > alpha)
           {
               alpha = value;
-              update_pv(ss, ply);
+              update_pv(ss);
           }
        }
     }
@@ -1631,7 +1631,7 @@ namespace {
         TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
     else if (bestValue >= beta)
     {
-        move = ss->pv[ply];
+        move = ss->pv[0];
         TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
 
         // Update killers only for good checking moves
@@ -1639,7 +1639,7 @@ namespace {
             update_killers(move, ss);
     }
     else
-        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss->pv[ply], ss->eval, ei.kingDanger[pos.side_to_move()]);
+        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss->pv[0], ss->eval, ei.kingDanger[pos.side_to_move()]);
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
@@ -1672,7 +1672,6 @@ namespace {
 
     Position pos(*sp->pos, threadID);
     CheckInfo ci(pos);
-    int ply = pos.ply();
     SearchStack* ss = sp->sstack[threadID] + 1;
     isCheck = pos.is_check();
 
@@ -1802,7 +1801,7 @@ namespace {
               if (PvNode && value < sp->beta) // This guarantees that always: sp->alpha < sp->beta
                   sp->alpha = value;
 
-              sp_update_pv(sp->parentSstack, ss, ply);
+              sp_update_pv(sp->parentSstack, ss);
           }
       }
     }
@@ -1818,18 +1817,16 @@ namespace {
   // It updates the PV in the SearchStack object corresponding to the
   // current node.
 
-  void update_pv(SearchStack* ss, int ply) {
-
-    assert(ply >= 0 && ply < PLY_MAX);
+  void update_pv(SearchStack* ss) {
 
-    int p;
+    Move* src = (ss+1)->pv;
+    Move* dst = ss->pv;
 
-    ss->pv[ply] = ss->currentMove;
+    *dst = ss->currentMove;
 
-    for (p = ply + 1; (ss+1)->pv[p] != MOVE_NONE; p++)
-        ss->pv[p] = (ss+1)->pv[p];
-
-    ss->pv[p] = MOVE_NONE;
+    do
+        *++dst = *src;
+    while (*src++ != MOVE_NONE);
   }
 
 
@@ -1837,18 +1834,17 @@ namespace {
   // difference between the two functions is that sp_update_pv also updates
   // the PV at the parent node.
 
-  void sp_update_pv(SearchStack* pss, SearchStack* ss, int ply) {
-
-    assert(ply >= 0 && ply < PLY_MAX);
-
-    int p;
+  void sp_update_pv(SearchStack* pss, SearchStack* ss) {
 
-    ss->pv[ply] = pss->pv[ply] = ss->currentMove;
+    Move* src = (ss+1)->pv;
+    Move* dst = ss->pv;
+    Move* pdst = pss->pv;
 
-    for (p = ply + 1; (ss+1)->pv[p] != MOVE_NONE; p++)
-        ss->pv[p] = pss->pv[p] = (ss+1)->pv[p];
+    *dst = *pdst = ss->currentMove;
 
-    ss->pv[p] = pss->pv[p] = MOVE_NONE;
+    do
+        *++dst = *++pdst = *src;
+    while (*src++ != MOVE_NONE);
   }
 
 
@@ -2253,7 +2249,7 @@ namespace {
 
         if (i < 3)
         {
-            ss->init(i);
+            ss->init();
             ss->initKillers();
         }
     }

diff --git a/src/search.h b/src/search.h
index 6e91159dd30284ec144f8fbfc369e0935e082e11..12f365dc536ede5625bd94b470033cd3a0ec269e 100644 (file)
--- a/src/search.h
+++ b/src/search.h
@@ -60,7 +60,7 @@ struct SearchStack {
   Value eval;
   bool skipNullMove;
 
-  void init(int ply);
+  void init();
   void initKillers();
 };