X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=6715d6808f3f26dc28261108247203b62eb1823f;hp=7ab74998295aa864750a2643a9bd56a5cb6e3bd5;hb=5f3c660d5d768ea5132439c5a8916673b909c0c9;hpb=f148a8f6ccbb57c440910ecfd4845c7f497b5404 diff --git a/src/search.cpp b/src/search.cpp index 7ab74998..6715d680 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -90,7 +90,7 @@ namespace { template void split(const Position& pos, SearchStack* ss, Value* alpha, const Value beta, Value* bestValue, - Depth depth, bool mateThreat, int* moveCount, MovePicker* mp, int master, bool pvNode); + Depth depth, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode); private: friend void poll(); @@ -285,10 +285,10 @@ namespace { Value root_search(Position& pos, SearchStack* ss, RootMoveList& rml, Value* alphaPtr, Value* betaPtr); template - Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int threadID); + Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int threadID); + Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth); template void sp_search(SplitPoint* sp, int threadID); @@ -603,7 +603,7 @@ namespace { Value id_loop(const Position& pos, Move searchMoves[]) { - Position p(pos); + Position p(pos, pos.thread()); SearchStack ss[PLY_MAX_PLUS_2]; Move EasyMove = MOVE_NONE; Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; @@ -811,7 +811,7 @@ namespace { // Step 5. Evaluate the position statically // At root we do this only to get reference value for child nodes if (!isCheck) - ss->eval = evaluate(pos, ei, 0); + ss->eval = evaluate(pos, ei); // Step 6. Razoring (omitted at root) // Step 7. Static null move pruning (omitted at root) @@ -876,7 +876,7 @@ namespace { alpha = -VALUE_INFINITE; // Full depth PV search, done on first move or after a fail high - value = -search(pos, ss+1, -beta, -alpha, newDepth, 0); + value = -search(pos, ss+1, -beta, -alpha, newDepth); } else { @@ -893,7 +893,7 @@ namespace { if (ss->reduction) { // Reduced depth non-pv search using alpha as upperbound - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 0); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction); doFullDepthSearch = (value > alpha); } } @@ -903,12 +903,12 @@ namespace { { // Full depth non-pv search using alpha as upperbound ss->reduction = Depth(0); - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth, 0); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth); // If we are above alpha then research at same depth but as PV // to get a correct score or eventually a fail high above beta. if (value > alpha) - value = -search(pos, ss+1, -beta, -alpha, newDepth, 0); + value = -search(pos, ss+1, -beta, -alpha, newDepth); } } @@ -1031,13 +1031,13 @@ namespace { // search<>() is the main search function for both PV and non-PV nodes template - Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int threadID) { + Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); assert(beta > alpha && beta <= VALUE_INFINITE); assert(PvNode || alpha == beta - 1); assert(pos.ply() > 0 && pos.ply() < PLY_MAX); - assert(threadID >= 0 && threadID < TM.active_threads()); + assert(pos.thread() >= 0 && pos.thread() < TM.active_threads()); Move movesSearched[256]; EvalInfo ei; @@ -1051,6 +1051,7 @@ namespace { bool isCheck, singleEvasion, moveIsCheck, captureOrPromotion, dangerous; bool mateThreat = false; int moveCount = 0; + int threadID = pos.thread(); int ply = pos.ply(); refinedValue = bestValue = value = -VALUE_INFINITE; oldAlpha = alpha; @@ -1117,7 +1118,7 @@ namespace { ei.kingDanger[pos.side_to_move()] = tte->king_danger(); } else - ss->eval = evaluate(pos, ei, threadID); + ss->eval = evaluate(pos, ei); refinedValue = refine_eval(tte, ss->eval, ply); // Enhance accuracy with TT value if possible update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval); @@ -1134,7 +1135,7 @@ namespace { && !pos.has_pawn_on_7th(pos.side_to_move())) { Value rbeta = beta - razor_margin(depth); - Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), threadID); + Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0)); if (v < rbeta) // Logically we should return (v + razor_margin(depth)), but // surprisingly this did slightly weaker in tests. @@ -1175,14 +1176,11 @@ namespace { R++; pos.do_null_move(st); - (ss+1)->skipNullMove = true; - nullValue = depth-R*OnePly < OnePly ? -qsearch(pos, ss+1, -beta, -alpha, Depth(0), threadID) - : - search(pos, ss+1, -beta, -alpha, depth-R*OnePly, threadID); - + nullValue = depth-R*OnePly < OnePly ? -qsearch(pos, ss+1, -beta, -alpha, Depth(0)) + : - search(pos, ss+1, -beta, -alpha, depth-R*OnePly); (ss+1)->skipNullMove = false; - pos.undo_null_move(); if (nullValue >= beta) @@ -1196,10 +1194,10 @@ namespace { return nullValue; ss->skipNullMove = true; - Value v = search(pos, ss, alpha, beta, depth-5*OnePly, threadID); + Value v = search(pos, ss, alpha, beta, depth-5*OnePly); ss->skipNullMove = false; - if (v >= beta) + if (v >= beta) return nullValue; } else @@ -1229,7 +1227,7 @@ namespace { Depth d = (PvNode ? depth - 2 * OnePly : depth / 2); ss->skipNullMove = true; - search(pos, ss, alpha, beta, d, threadID); + search(pos, ss, alpha, beta, d); ss->skipNullMove = false; ttMove = ss->pv[ply]; @@ -1281,7 +1279,7 @@ namespace { Value b = ttValue - SingularExtensionMargin; ss->excludedMove = move; ss->skipNullMove = true; - Value v = search(pos, ss, b - 1, b, depth / 2, threadID); + Value v = search(pos, ss, b - 1, b, depth / 2); ss->skipNullMove = false; ss->excludedMove = MOVE_NONE; @@ -1330,8 +1328,8 @@ namespace { // Step extra. pv search (only in PV nodes) // The first move in list is the expected PV if (PvNode && moveCount == 1) - value = newDepth < OnePly ? -qsearch(pos, ss+1, -beta, -alpha, Depth(0), threadID) - : - search(pos, ss+1, -beta, -alpha, newDepth, threadID); + value = newDepth < OnePly ? -qsearch(pos, ss+1, -beta, -alpha, Depth(0)) + : - search(pos, ss+1, -beta, -alpha, newDepth); else { // Step 14. Reduced depth search @@ -1348,8 +1346,8 @@ namespace { if (ss->reduction) { Depth d = newDepth - ss->reduction; - value = d < OnePly ? -qsearch(pos, ss+1, -(alpha+1), -alpha, Depth(0), threadID) - : - search(pos, ss+1, -(alpha+1), -alpha, d, threadID); + value = d < OnePly ? -qsearch(pos, ss+1, -(alpha+1), -alpha, Depth(0)) + : - search(pos, ss+1, -(alpha+1), -alpha, d); doFullDepthSearch = (value > alpha); } @@ -1362,7 +1360,7 @@ namespace { assert(newDepth - OnePly >= OnePly); ss->reduction = OnePly; - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, threadID); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction); doFullDepthSearch = (value > alpha); } ss->reduction = Depth(0); // Restore original reduction @@ -1371,15 +1369,15 @@ namespace { // Step 15. Full depth search if (doFullDepthSearch) { - value = newDepth < OnePly ? -qsearch(pos, ss+1, -(alpha+1), -alpha, Depth(0), threadID) - : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, threadID); + value = newDepth < OnePly ? -qsearch(pos, ss+1, -(alpha+1), -alpha, Depth(0)) + : - search(pos, ss+1, -(alpha+1), -alpha, newDepth); // Step extra. pv search (only in PV nodes) // Search only for possible new PV nodes, if instead value >= beta then // parent node fails low with value <= alpha and tries another move. if (PvNode && value > alpha && value < beta) - value = newDepth < OnePly ? -qsearch(pos, ss+1, -beta, -alpha, Depth(0), threadID) - : - search(pos, ss+1, -beta, -alpha, newDepth, threadID); + value = newDepth < OnePly ? -qsearch(pos, ss+1, -beta, -alpha, Depth(0)) + : - search(pos, ss+1, -beta, -alpha, newDepth); } } @@ -1413,7 +1411,7 @@ namespace { && !TM.thread_should_stop(threadID) && Iteration <= 99) TM.split(pos, ss, &alpha, beta, &bestValue, depth, - mateThreat, &moveCount, &mp, threadID, PvNode); + mateThreat, &moveCount, &mp, PvNode); } // Step 19. Check for mate and stalemate @@ -1457,26 +1455,27 @@ namespace { // less than OnePly). template - Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int threadID) { + Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) { assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE); assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE); assert(PvNode || alpha == beta - 1); assert(depth <= 0); assert(pos.ply() > 0 && pos.ply() < PLY_MAX); - assert(threadID >= 0 && threadID < TM.active_threads()); + assert(pos.thread() >= 0 && pos.thread() < TM.active_threads()); EvalInfo ei; StateInfo st; Move ttMove, move; - Value staticValue, bestValue, value, futilityBase, futilityValue; + Value staticValue, bestValue, value, futilityBase; bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable; const TTEntry* tte = NULL; int moveCount = 0; int ply = pos.ply(); Value oldAlpha = alpha; + Value futilityValue = VALUE_INFINITE; - TM.incrementNodeCounter(threadID); + TM.incrementNodeCounter(pos.thread()); ss->init(ply); // Check for an instant draw or maximum ply reached @@ -1505,7 +1504,7 @@ namespace { ei.kingDanger[pos.side_to_move()] = tte->king_danger(); } else - staticValue = evaluate(pos, ei, threadID); + staticValue = evaluate(pos, ei); if (!isCheck) { @@ -1526,7 +1525,7 @@ namespace { return bestValue; } - if (bestValue > alpha) + if (PvNode && bestValue > alpha) alpha = bestValue; // If we are near beta then try to get a cutoff pushing checks a bit further @@ -1562,6 +1561,11 @@ namespace { && !move_is_promotion(move) && !pos.move_is_passed_pawn_push(move)) { + // Can only decrease from previous move because of + // MVV ordering so we don't need to recheck. + if (futilityValue < alpha) + continue; + futilityValue = futilityBase + pos.endgame_value_of_piece_on(move_to(move)) + (move_is_ep(move) ? PawnValueEndgame : Value(0)); @@ -1591,7 +1595,7 @@ namespace { // Make and search the move pos.do_move(move, st, ci, moveIsCheck); - value = -qsearch(pos, ss+1, -beta, -alpha, depth-OnePly, threadID); + value = -qsearch(pos, ss+1, -beta, -alpha, depth-OnePly); pos.undo_move(move); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); @@ -1662,7 +1666,7 @@ namespace { int moveCount; value = -VALUE_INFINITE; - Position pos(*sp->pos); + Position pos(*sp->pos, threadID); CheckInfo ci(pos); int ply = pos.ply(); SearchStack* ss = sp->sstack[threadID] + 1; @@ -1739,8 +1743,8 @@ namespace { { Value localAlpha = sp->alpha; Depth d = newDepth - ss->reduction; - value = d < OnePly ? -qsearch(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0), threadID) - : - search(pos, ss+1, -(localAlpha+1), -localAlpha, d, threadID); + value = d < OnePly ? -qsearch(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0)) + : - search(pos, ss+1, -(localAlpha+1), -localAlpha, d); doFullDepthSearch = (value > localAlpha); } @@ -1753,7 +1757,7 @@ namespace { ss->reduction = OnePly; Value localAlpha = sp->alpha; - value = -search(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth-ss->reduction, threadID); + value = -search(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth-ss->reduction); doFullDepthSearch = (value > localAlpha); } ss->reduction = Depth(0); // Restore original reduction @@ -1763,15 +1767,15 @@ namespace { if (doFullDepthSearch) { Value localAlpha = sp->alpha; - value = newDepth < OnePly ? -qsearch(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0), threadID) - : - search(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth, threadID); + value = newDepth < OnePly ? -qsearch(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0)) + : - search(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth); // Step extra. pv search (only in PV nodes) // Search only for possible new PV nodes, if instead value >= beta then // parent node fails low with value <= alpha and tries another move. if (PvNode && value > localAlpha && value < sp->beta) - value = newDepth < OnePly ? -qsearch(pos, ss+1, -sp->beta, -sp->alpha, Depth(0), threadID) - : - search(pos, ss+1, -sp->beta, -sp->alpha, newDepth, threadID); + value = newDepth < OnePly ? -qsearch(pos, ss+1, -sp->beta, -sp->alpha, Depth(0)) + : - search(pos, ss+1, -sp->beta, -sp->alpha, newDepth); } // Step 16. Undo move @@ -2621,16 +2625,18 @@ namespace { template void ThreadsManager::split(const Position& p, SearchStack* ss, Value* alpha, const Value beta, Value* bestValue, Depth depth, bool mateThreat, int* moveCount, - MovePicker* mp, int master, bool pvNode) { + MovePicker* mp, bool pvNode) { assert(p.is_ok()); assert(*bestValue >= -VALUE_INFINITE); assert(*bestValue <= *alpha); assert(*alpha < beta); assert(beta <= VALUE_INFINITE); assert(depth > Depth(0)); - assert(master >= 0 && master < ActiveThreads); + assert(p.thread() >= 0 && p.thread() < ActiveThreads); assert(ActiveThreads > 1); + int master = p.thread(); + lock_grab(&MPLock); // If no other thread is available to help us, or if we have too many @@ -2782,7 +2788,7 @@ namespace { init_ss_array(ss, PLY_MAX_PLUS_2); pos.do_move(cur->move, st); moves[count].move = cur->move; - moves[count].score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 0); + moves[count].score = -qsearch(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, Depth(0)); moves[count].pv[0] = cur->move; moves[count].pv[1] = MOVE_NONE; pos.undo_move(cur->move);