X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=4592ac084ebc56d60a59b83415167bd2f75af146;hp=515787c1042da05329220c2737b866be0f3d2da2;hb=b638f6b0354ea124dc80e5e38189474d34141e2d;hpb=55f0d6377f7828fb43428ed643a99780053dd589

diff --git a/src/search.cpp b/src/search.cpp
index 515787c1..4592ac08 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2009 Marco Costalba
+  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -254,10 +254,10 @@ namespace {
   int MultiPV;
 
   // Time managment variables
-  int RootMoveNumber, SearchStartTime, MaxNodes, MaxDepth;
-  int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
+  int SearchStartTime, MaxNodes, MaxDepth, MaxSearchTime;
+  int AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
   bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
-  bool AbortSearch, Quit, AspirationFailLow;
+  bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
 
   // Show current line?
   bool ShowCurrentLine;
@@ -282,7 +282,7 @@ namespace {
   /// Local functions
 
   Value id_loop(const Position& pos, Move searchMoves[]);
-  Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta);
+  Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
   Value search_pv(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
   Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID, Move excludedMove = MOVE_NONE);
   Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
@@ -373,6 +373,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
 
   // Initialize global search variables
   StopOnPonderhit = AbortSearch = Quit = AspirationFailLow = false;
+  MaxSearchTime = AbsoluteMaxSearchTime = ExtraSearchTime = 0;
   NodesSincePoll = 0;
   TM.resetNodeCounters();
   SearchStartTime = get_system_time();
@@ -440,10 +441,6 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
   {
       TM.set_active_threads(newActiveThreads);
       init_eval(TM.active_threads());
-      // HACK: init_eval() destroys the static castleRightsMask[] array in the
-      // Position class. The below line repairs the damage.
-      Position p(pos.to_fen());
-      assert(pos.is_ok());
   }
 
   // Wake up sleeping threads
@@ -647,8 +644,6 @@ namespace {
         // Initialize iteration
         Iteration++;
         BestMoveChangesByIteration[Iteration] = 0;
-        if (Iteration <= 5)
-            ExtraSearchTime = 0;
 
         cout << "info depth " << Iteration << endl;
 
@@ -665,8 +660,8 @@ namespace {
             beta  = Min(ValueByIteration[Iteration - 1] + AspirationDelta,  VALUE_INFINITE);
         }
 
-        // Search to the current depth, rml is updated and sorted
-        value = root_search(p, ss, rml, alpha, beta);
+        // Search to the current depth, rml is updated and sorted, alpha and beta could change
+        value = root_search(p, ss, rml, &alpha, &beta);
 
         // Write PV to transposition table, in case the relevant entries have
         // been overwritten during the search.
@@ -786,18 +781,21 @@ namespace {
   // scheme, prints some information to the standard output and handles
   // the fail low/high loops.
 
-  Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta) {
+  Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
 
     EvalInfo ei;
     StateInfo st;
+    CheckInfo ci(pos);
     int64_t nodes;
     Move move;
     Depth depth, ext, newDepth;
-    Value value, alpha;
+    Value value, alpha, beta;
     bool isCheck, moveIsCheck, captureOrPromotion, dangerous;
-    int researchCount = 0;
-    CheckInfo ci(pos);
-    alpha = oldAlpha;
+    int researchCountFH, researchCountFL;
+
+    researchCountFH = researchCountFL = 0;
+    alpha = *alphaPtr;
+    beta = *betaPtr;
     isCheck = pos.is_check();
 
     // Step 1. Initialize node and poll (omitted at root, but I can see no good reason for this, FIXME)
@@ -828,8 +826,8 @@ namespace {
         // Step 10. Loop through all moves in the root move list
         for (int i = 0; i <  rml.move_count() && !AbortSearch; i++)
         {
-            // This is used by time management and starts from 1
-            RootMoveNumber = i + 1;
+            // This is used by time management
+            FirstRootMove = (i == 0);
 
             // Save the current node count before the move is searched
             nodes = TM.nodes_searched();
@@ -843,7 +841,7 @@ namespace {
 
             if (current_search_time() >= 1000)
                 cout << "info currmove " << move
-                     << " currmovenumber " << RootMoveNumber << endl;
+                     << " currmovenumber " << i + 1 << endl;
 
             moveIsCheck = pos.move_is_check(move);
             captureOrPromotion = pos.move_is_capture_or_promotion(move);
@@ -929,8 +927,8 @@ namespace {
                 print_pv_info(pos, ss, alpha, beta, value);
 
                 // Prepare for a research after a fail high, each time with a wider window
-                researchCount++;
-                beta = Min(beta + AspirationDelta * (1 << researchCount), VALUE_INFINITE);
+                *betaPtr = beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
+                researchCountFH++;
 
             } // End of fail high loop
 
@@ -950,6 +948,7 @@ namespace {
             rml.set_move_nodes(i, TM.nodes_searched() - nodes);
 
             assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
+            assert(value < beta);
 
             // Step 17. Check for new best move
             if (value <= alpha && i >= MultiPV)
@@ -975,8 +974,7 @@ namespace {
                     // Print information to the standard output
                     print_pv_info(pos, ss, alpha, beta, value);
 
-                    // Raise alpha to setup proper non-pv search upper bound, note
-                    // that we can end up with alpha >= beta and so get a fail high.
+                    // Raise alpha to setup proper non-pv search upper bound
                     if (value > alpha)
                         alpha = value;
                 }
@@ -1002,22 +1000,21 @@ namespace {
                 }
             } // PV move or new best move
 
-            assert(alpha >= oldAlpha);
+            assert(alpha >= *alphaPtr);
 
-            AspirationFailLow = (alpha == oldAlpha);
+            AspirationFailLow = (alpha == *alphaPtr);
 
             if (AspirationFailLow && StopOnPonderhit)
                 StopOnPonderhit = false;
         }
 
         // Can we exit fail low loop ?
-        if (AbortSearch || alpha > oldAlpha)
+        if (AbortSearch || !AspirationFailLow)
             break;
 
         // Prepare for a research after a fail low, each time with a wider window
-        researchCount++;
-        alpha = Max(alpha - AspirationDelta * (1 << researchCount), -VALUE_INFINITE);
-        oldAlpha = alpha;
+        *alphaPtr = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
+        researchCountFL++;
 
     } // Fail low loop
 
@@ -2480,7 +2477,7 @@ namespace {
     if (PonderSearch)
         return;
 
-    bool stillAtFirstMove =    RootMoveNumber == 1
+    bool stillAtFirstMove =    FirstRootMove
                            && !AspirationFailLow
                            &&  t > MaxSearchTime + ExtraSearchTime;
 
@@ -2503,7 +2500,7 @@ namespace {
     int t = current_search_time();
     PonderSearch = false;
 
-    bool stillAtFirstMove =    RootMoveNumber == 1
+    bool stillAtFirstMove =    FirstRootMove
                            && !AspirationFailLow
                            &&  t > MaxSearchTime + ExtraSearchTime;