From: Marco Costalba Date: Sun, 23 Jan 2011 07:36:12 +0000 (+0100) Subject: Remove special Root cases X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=79b1a7417ffad171327a65ff80af7950f12fddfa Remove special Root cases So to better spot where the differences really count. Also add some more additional cleanup. Harmless functional change and no regression. After 5780 games Mod- Orig: 931 - 955 - 3894 ELO -1 (+- 3.6) Signed-off-by: Marco Costalba --- diff --git a/src/search.cpp b/src/search.cpp index b75f6279..6d75cc3d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -248,7 +248,7 @@ namespace { // Book object Book OpeningBook; - // Pointer to root move list + // Root move list RootMoveList Rml; // MultiPV mode @@ -321,69 +321,70 @@ namespace { #endif - // A dispatcher to choose among different move sources according to the type of node + // MovePickerExt is an extended MovePicker used to choose at compile time + // the proper move source according to the type of node. template struct MovePickerExt; - // In Root nodes use RootMoveList Rml as source. Score and sort the moves before to search them. - template<> struct MovePickerExt : private MovePicker { - - MovePickerExt(const Position& p, Move, Depth, const History& h, SearchStack* ss, Value beta) - : MovePicker(p, Rml[0].pv[0], ONE_PLY, h, ss, beta), firstCall(true) { // FIXME use depth - - Move move; - Value score = VALUE_ZERO; - - // Score root moves using the standard way used in main search, the moves - // are scored according to the order in which are returned by MovePicker. - // This is the second order score that is used to compare the moves when - // the first order pv scores of both moves are equal. - while ((move = MovePicker::get_next_move()) != MOVE_NONE) - for (rm = Rml.begin(); rm != Rml.end(); ++rm) - if (rm->pv[0] == move) - { - rm->non_pv_score = score--; - break; - } + // In Root nodes use RootMoveList Rml as source. Score and sort the root moves + // before to search them. + template<> struct MovePickerExt : public MovePicker { + + MovePickerExt(const Position& p, Move, Depth d, const History& h, SearchStack* ss, Value b) + : MovePicker(p, Rml[0].pv[0], d, h, ss, b), firstCall(true) { + Move move; + Value score = VALUE_ZERO; + + // Score root moves using the standard way used in main search, the moves + // are scored according to the order in which are returned by MovePicker. + // This is the second order score that is used to compare the moves when + // the first order pv scores of both moves are equal. + while ((move = MovePicker::get_next_move()) != MOVE_NONE) + for (rm = Rml.begin(); rm != Rml.end(); ++rm) + if (rm->pv[0] == move) + { + rm->non_pv_score = score--; + break; + } - Rml.sort(); - rm = Rml.begin(); - } + Rml.sort(); + rm = Rml.begin(); + } - Move get_next_move() { + Move get_next_move() { - if (!firstCall) - ++rm; - else - firstCall = false; + if (!firstCall) + ++rm; + else + firstCall = false; - return rm != Rml.end() ? rm->pv[0] : MOVE_NONE; - } - int number_of_evasions() const { return (int)Rml.size(); } + return rm != Rml.end() ? rm->pv[0] : MOVE_NONE; + } + int number_of_evasions() const { return (int)Rml.size(); } - RootMoveList::iterator rm; - bool firstCall; + RootMoveList::iterator rm; + bool firstCall; }; - // In SpNodes use split point's shared MovePicker as move source - template<> struct MovePickerExt { + // In SpNodes use split point's shared MovePicker object as move source + template<> struct MovePickerExt : public MovePicker { - MovePickerExt(const Position&, Move, Depth, const History&, SearchStack* ss, Value) - : mp(ss->sp->mp) {} + MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, + SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b), + mp(ss->sp->mp) {} - Move get_next_move() { return mp->get_next_move(); } - int number_of_evasions() const { return mp->number_of_evasions(); } + Move get_next_move() { return mp->get_next_move(); } - RootMoveList::iterator rm; // Dummy, never used - MovePicker* mp; + RootMoveList::iterator rm; // Dummy, needed to compile + MovePicker* mp; }; - // Normal case, create and use a MovePicker object as source + // Default case, create and use a MovePicker object as source template<> struct MovePickerExt : public MovePicker { - MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, - SearchStack* ss, Value beta) : MovePicker(p, ttm, d, h, ss, beta) {} + MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, + SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b) {} - RootMoveList::iterator rm; // Dummy, never used + RootMoveList::iterator rm; // Dummy, needed to compile }; } // namespace @@ -602,10 +603,9 @@ bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[ namespace { - // id_loop() is the main iterative deepening loop. It calls search() - // repeatedly with increasing depth until the allocated thinking time has - // been consumed, the user stops the search, or the maximum search depth is - // reached. + // id_loop() is the main iterative deepening loop. It calls search() repeatedly + // with increasing depth until the allocated thinking time has been consumed, + // user stops the search, or the maximum search depth is reached. Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove) { @@ -615,7 +615,7 @@ namespace { int iteration, researchCountFL, researchCountFH, aspirationDelta; Value value, alpha, beta; Depth depth; - Move EasyMove; + Move bestMove, easyMove; // Moves to search are verified, scored and sorted Rml.init(pos, searchMoves); @@ -625,9 +625,10 @@ namespace { H.clear(); memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack)); alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; - EasyMove = MOVE_NONE; + *ponderMove = bestMove = easyMove = MOVE_NONE; aspirationDelta = 0; iteration = 1; + ss->currentMove = MOVE_NULL; // Hack to skip update_gains() // Handle special case of searching on a mate/stale position if (Rml.size() == 0) @@ -647,7 +648,7 @@ namespace { // Is one move significantly better than others after initial scoring ? if ( Rml.size() == 1 || Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin) - EasyMove = Rml[0].pv[0]; + easyMove = Rml[0].pv[0]; // Iterative deepening loop while (++iteration <= PLY_MAX && (!MaxDepth || iteration <= MaxDepth) && !StopRequest) @@ -670,27 +671,24 @@ namespace { beta = Min(bestValues[iteration - 1] + aspirationDelta, VALUE_INFINITE); } - // We start with small aspiration window and in case of fail high/low, we - // research with bigger window until we are not failing high/low anymore. + // Start with a small aspiration window and, in case of fail high/low, + // research with bigger window until not failing high/low anymore. while (true) { - // Search to the current depth - value = search(pos, ss, alpha, beta, depth, 0); + // Search starting from ss+1 to allow calling update_gains() + value = search(pos, ss+1, alpha, beta, depth, 0); - // Sort root moves and write PV lines to transposition table, in case - // the relevant entries have been overwritten during the search. - Rml.sort(); + // Write PV lines to transposition table, in case the relevant entries + // have been overwritten during the search. for (int i = 0; i < Min(MultiPV, (int)Rml.size()); i++) Rml[i].insert_pv_in_tt(pos); // Value cannot be trusted. Break out immediately! if (StopRequest) - break; // FIXME move to 'while' condition + break; assert(value >= alpha); - bestMoveChanges[iteration] = Rml.bestMoveChanges; // FIXME move outside fail high/low loop - // In case of failing high/low increase aspiration window and research, // otherwise exit the fail high/low loop. if (value >= beta) @@ -710,33 +708,33 @@ namespace { break; } - //Save info about search result + // Collect info about search result + bestMove = Rml[0].pv[0]; bestValues[iteration] = value; + bestMoveChanges[iteration] = Rml.bestMoveChanges; // Drop the easy move if differs from the new best move - if (Rml[0].pv[0] != EasyMove) - EasyMove = MOVE_NONE; + if (bestMove != easyMove) + easyMove = MOVE_NONE; if (UseTimeManagement && !StopRequest) { // Time to stop? bool noMoreTime = false; - // Stop search early if there is only a single legal move, - // we search up to Iteration 6 anyway to get a proper score. - if (iteration >= 6 && Rml.size() == 1) - noMoreTime = true; - // Stop search early when the last two iterations returned a mate score if ( iteration >= 6 && abs(bestValues[iteration]) >= abs(VALUE_MATE) - 100 && abs(bestValues[iteration-1]) >= abs(VALUE_MATE) - 100) noMoreTime = true; - // Stop search early if one move seems to be much better than the others + // Stop search early if one move seems to be much better than the + // others or if there is only a single legal move. In this latter + // case we search up to Iteration 8 anyway to get a proper score. if ( iteration >= 8 - && EasyMove == Rml[0].pv[0] - && ( ( Rml[0].nodes > (pos.nodes_searched() * 85) / 100 + && easyMove == bestMove + && ( Rml.size() == 1 + ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100 && current_search_time() > TimeMgr.available_time() / 16) ||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100 && current_search_time() > TimeMgr.available_time() / 32))) @@ -763,7 +761,7 @@ namespace { } *ponderMove = Rml[0].pv[1]; - return Rml[0].pv[0]; + return bestMove; } @@ -819,30 +817,26 @@ namespace { ss->currentMove = ss->bestMove = threatMove = MOVE_NONE; (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE; - if (!Root) // FIXME remove + if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls) { - if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls) - { - NodesSincePoll = 0; - poll(pos); - } - - // Step 2. Check for aborted search and immediate draw - if ( StopRequest - || ThreadsMgr.cutoff_at_splitpoint(threadID) - || pos.is_draw() - || ply >= PLY_MAX - 1) - return VALUE_DRAW; - - // Step 3. Mate distance pruning - alpha = Max(value_mated_in(ply), alpha); - beta = Min(value_mate_in(ply+1), beta); - if (alpha >= beta) - return alpha; + NodesSincePoll = 0; + poll(pos); } - // Step 4. Transposition table lookup + // Step 2. Check for aborted search and immediate draw + if (( StopRequest + || ThreadsMgr.cutoff_at_splitpoint(threadID) + || pos.is_draw() + || ply >= PLY_MAX - 1) && !Root) + return VALUE_DRAW; + + // Step 3. Mate distance pruning + alpha = Max(value_mated_in(ply), alpha); + beta = Min(value_mate_in(ply+1), beta); + if (alpha >= beta) + return alpha; + // Step 4. Transposition table lookup // We don't want the score of a partial search to overwrite a previous full search // TT value, so we use a different position key in case of an excluded move exists. excludedMove = ss->excludedMove; @@ -884,8 +878,7 @@ namespace { } // Save gain for the parent non-capture move - if (!Root) - update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval); + update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval); // Step 6. Razoring (is omitted in PV nodes) if ( !PvNode @@ -978,9 +971,8 @@ namespace { } // Step 9. Internal iterative deepening - if ( !Root - && depth >= IIDDepth[PvNode] - && ttMove == MOVE_NONE + if ( depth >= IIDDepth[PvNode] + && ttMove == MOVE_NONE && (PvNode || (!isCheck && ss->eval >= beta - IIDMargin))) { Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2); @@ -994,7 +986,7 @@ namespace { } // Expensive mate threat detection (only for PV nodes) - if (PvNode && !Root) // FIXME + if (PvNode) mateThreat = pos.has_mate_threat(); split_point_start: // At split points actual search starts from here @@ -1304,7 +1296,7 @@ split_point_start: // At split points actual search starts from here && !StopRequest && !ThreadsMgr.cutoff_at_splitpoint(threadID)) ThreadsMgr.split(pos, ss, ply, &alpha, beta, &bestValue, depth, - threatMove, mateThreat, moveCount, (MovePicker*)&mp, PvNode); + threatMove, mateThreat, moveCount, &mp, PvNode); } // Step 19. Check for mate and stalemate