X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=7b7bc5cd8ec00b4b4b2f056046c8560eabf25408;hp=e9c0ad26a27b1ba13e063c3d8d64ec7350c6491f;hb=92dcbfa658a66ccc633ff24dd3402f90451712ed;hpb=b6e9d901b0f82e8500acfad590649bdad9a7756f diff --git a/src/search.cpp b/src/search.cpp index e9c0ad26..7b7bc5cd 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -91,7 +91,7 @@ namespace { CountermovesStats Countermoves; template - Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode); template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); @@ -155,21 +155,17 @@ void Search::init() { size_t Search::perft(Position& pos, Depth depth) { - // At the last ply just return the number of legal moves (leaf nodes) - if (depth == ONE_PLY) - return MoveList(pos).size(); - StateInfo st; size_t cnt = 0; CheckInfo ci(pos); + const bool leaf = depth == 2 * ONE_PLY; for (MoveList it(pos); *it; ++it) { pos.do_move(*it, st, ci, pos.move_gives_check(*it, ci)); - cnt += perft(pos, depth - ONE_PLY); + cnt += leaf ? MoveList(pos).size() : perft(pos, depth - ONE_PLY); pos.undo_move(*it); } - return cnt; } @@ -349,7 +345,7 @@ namespace { // research with bigger window until not failing high/low anymore. while (true) { - bestValue = search(pos, ss, alpha, beta, depth * ONE_PLY); + bestValue = search(pos, ss, alpha, beta, depth * ONE_PLY, false); // Bring to front the best move. It is critical that sorting is // done with a stable algorithm because all the values but the first @@ -455,7 +451,7 @@ namespace { Value rBeta = bestValue - 2 * PawnValueMg; ss->excludedMove = RootMoves[0].pv[0]; ss->skipNullMove = true; - Value v = search(pos, ss, rBeta - 1, rBeta, (depth - 3) * ONE_PLY); + Value v = search(pos, ss, rBeta - 1, rBeta, (depth - 3) * ONE_PLY, true); ss->skipNullMove = false; ss->excludedMove = MOVE_NONE; @@ -485,7 +481,7 @@ namespace { // here: This is taken care of after we return from the split point. template - Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { + Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) { const bool PvNode = (NT == PV || NT == Root || NT == SplitPointPV || NT == SplitPointRoot); const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV || NT == SplitPointRoot); @@ -574,9 +570,9 @@ namespace { && tte && tte->depth() >= depth && ttValue != VALUE_NONE // Only in case of TT access race - && ( PvNode ? tte->type() == BOUND_EXACT - : ttValue >= beta ? (tte->type() & BOUND_LOWER) - : (tte->type() & BOUND_UPPER))) + && ( PvNode ? tte->bound() == BOUND_EXACT + : ttValue >= beta ? (tte->bound() & BOUND_LOWER) + : (tte->bound() & BOUND_UPPER))) { TT.refresh(tte); ss->currentMove = ttMove; // Can be MOVE_NONE @@ -605,8 +601,8 @@ namespace { // Can ttValue be used as a better position evaluation? if (ttValue != VALUE_NONE) - if ( ((tte->type() & BOUND_LOWER) && ttValue > eval) - || ((tte->type() & BOUND_UPPER) && ttValue < eval)) + if ( ((tte->bound() & BOUND_LOWER) && ttValue > eval) + || ((tte->bound() & BOUND_UPPER) && ttValue < eval)) eval = ttValue; } else @@ -618,10 +614,10 @@ namespace { // Update gain for the parent non-capture move given the static position // evaluation before and after the move. - if ( (move = (ss-1)->currentMove) != MOVE_NULL - && (ss-1)->staticEval != VALUE_NONE + if ( !pos.captured_piece_type() && ss->staticEval != VALUE_NONE - && !pos.captured_piece_type() + && (ss-1)->staticEval != VALUE_NONE + && (move = (ss-1)->currentMove) != MOVE_NULL && type_of(move) == NORMAL) { Square to = to_sq(move); @@ -679,7 +675,7 @@ namespace { pos.do_null_move(st); (ss+1)->skipNullMove = true; nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, depth-R); + : - search(pos, ss+1, -beta, -alpha, depth-R, !cutNode); (ss+1)->skipNullMove = false; pos.undo_null_move(); @@ -694,7 +690,7 @@ namespace { // Do verification search at high depths ss->skipNullMove = true; - Value v = search(pos, ss, alpha, beta, depth-R); + Value v = search(pos, ss, alpha, beta, depth-R, false); ss->skipNullMove = false; if (v >= beta) @@ -726,7 +722,6 @@ namespace { && depth >= 5 * ONE_PLY && !inCheck && !ss->skipNullMove - && excludedMove == MOVE_NONE && abs(beta) < VALUE_MATE_IN_MAX_PLY) { Value rbeta = beta + 200; @@ -744,7 +739,7 @@ namespace { { ss->currentMove = move; pos.do_move(move, st, ci, pos.move_gives_check(move, ci)); - value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth); + value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode); pos.undo_move(move); if (value >= rbeta) return value; @@ -759,7 +754,7 @@ namespace { Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4); ss->skipNullMove = true; - search(pos, ss, alpha, beta, d); + search(pos, ss, alpha, beta, d, true); ss->skipNullMove = false; tte = TT.probe(posKey); @@ -780,7 +775,7 @@ split_point_start: // At split points actual search starts from here && depth >= (PvNode ? 6 * ONE_PLY : 8 * ONE_PLY) && ttMove != MOVE_NONE && !excludedMove // Recursive singular search is not allowed - && (tte->type() & BOUND_LOWER) + && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3 * ONE_PLY; // Step 11. Loop through moves @@ -855,7 +850,7 @@ split_point_start: // At split points actual search starts from here Value rBeta = ttValue - int(depth); ss->excludedMove = move; ss->skipNullMove = true; - value = search(pos, ss, rBeta - 1, rBeta, depth / 2); + value = search(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode); ss->skipNullMove = false; ss->excludedMove = MOVE_NONE; @@ -948,6 +943,10 @@ split_point_start: // At split points actual search starts from here && move != ss->killers[1]) { ss->reduction = reduction(depth, moveCount); + + if (!PvNode && cutNode) + ss->reduction += ONE_PLY; + if (move == countermoves[0] || move == countermoves[1]) ss->reduction = std::max(DEPTH_ZERO, ss->reduction-ONE_PLY); @@ -955,7 +954,7 @@ split_point_start: // At split points actual search starts from here if (SpNode) alpha = splitPoint->alpha; - value = -search(pos, ss+1, -(alpha+1), -alpha, d); + value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO); ss->reduction = DEPTH_ZERO; @@ -972,7 +971,7 @@ split_point_start: // At split points actual search starts from here value = newDepth < ONE_PLY ? givesCheck ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) : -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -(alpha+1), -alpha, newDepth); + : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); } // Only for PV nodes do a full PV search on the first move or after a fail @@ -982,7 +981,7 @@ split_point_start: // At split points actual search starts from here value = newDepth < ONE_PLY ? givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) : -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, newDepth); + : - search(pos, ss+1, -beta, -alpha, newDepth, false); // Step 17. Undo move pos.undo_move(move); @@ -1057,7 +1056,7 @@ split_point_start: // At split points actual search starts from here assert(bestValue < beta); thisThread->split(pos, ss, alpha, beta, &bestValue, &bestMove, - depth, threatMove, moveCount, &mp, NT); + depth, threatMove, moveCount, &mp, NT, cutNode); if (bestValue >= beta) break; } @@ -1173,9 +1172,9 @@ split_point_start: // At split points actual search starts from here if ( tte && tte->depth() >= ttDepth && ttValue != VALUE_NONE // Only in case of TT access race - && ( PvNode ? tte->type() == BOUND_EXACT - : ttValue >= beta ? (tte->type() & BOUND_LOWER) - : (tte->type() & BOUND_UPPER))) + && ( PvNode ? tte->bound() == BOUND_EXACT + : ttValue >= beta ? (tte->bound() & BOUND_LOWER) + : (tte->bound() & BOUND_UPPER))) { ss->currentMove = ttMove; // Can be MOVE_NONE return ttValue; @@ -1585,7 +1584,7 @@ split_point_start: // At split points actual search starts from here void RootMove::extract_pv_from_tt(Position& pos) { StateInfo state[MAX_PLY_PLUS_2], *st = state; - TTEntry* tte; + const TTEntry* tte; int ply = 0; Move m = pv[0]; @@ -1618,7 +1617,7 @@ void RootMove::extract_pv_from_tt(Position& pos) { void RootMove::insert_pv_in_tt(Position& pos) { StateInfo state[MAX_PLY_PLUS_2], *st = state; - TTEntry* tte; + const TTEntry* tte; int ply = 0; do { @@ -1705,13 +1704,13 @@ void Thread::idle_loop() { switch (sp->nodeType) { case Root: - search(pos, ss, sp->alpha, sp->beta, sp->depth); + search(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode); break; case PV: - search(pos, ss, sp->alpha, sp->beta, sp->depth); + search(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode); break; case NonPV: - search(pos, ss, sp->alpha, sp->beta, sp->depth); + search(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode); break; default: assert(false);