X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=0f599fc29f88d9d37e38bea7d0301f62079d5cc0;hp=98e3e945d5537ac777d19ab4c608c63b74929c9e;hb=b605103a34be5bea7815ab3f6d4a21d487d0182b;hpb=2c5dfb312205de03239cb15e79b501789c4cd067 diff --git a/src/search.cpp b/src/search.cpp index 98e3e945..0f599fc2 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -101,7 +101,7 @@ namespace { template Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning); - template + template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth = DEPTH_ZERO); Value value_to_tt(Value v, int ply); @@ -654,7 +654,7 @@ namespace { if (inCheck) { ss->staticEval = eval = VALUE_NONE; - improving = true; + improving = false; goto moves_loop; } else if (ttHit) @@ -690,12 +690,12 @@ namespace { { if ( depth == ONE_PLY && eval + RazorMargin1 <= alpha) - return qsearch(pos, ss, alpha, alpha+1); + return qsearch(pos, ss, alpha, alpha+1); else if (eval + RazorMargin2 <= alpha) { Value ralpha = alpha - RazorMargin2; - Value v = qsearch(pos, ss, ralpha, ralpha+1); + Value v = qsearch(pos, ss, ralpha, ralpha+1); if (v <= ralpha) return v; @@ -724,7 +724,7 @@ namespace { ss->contHistory = thisThread->contHistory[NO_PIECE][0].get(); pos.do_null_move(st); - Value nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1) + Value nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1) : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true); pos.undo_null_move(); @@ -742,7 +742,7 @@ namespace { thisThread->nmp_ply = ss->ply + 3 * (depth-R) / 4; thisThread->nmp_odd = ss->ply % 2; - Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta) + Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta) : search(pos, ss, beta-1, beta, depth-R, false, true); thisThread->nmp_odd = thisThread->nmp_ply = 0; @@ -761,12 +761,12 @@ namespace { { assert(is_ok((ss-1)->currentMove)); - Value rbeta = std::min(beta + 200, VALUE_INFINITE); + Value rbeta = std::min(beta + 216 - 48 * improving, VALUE_INFINITE); MovePicker mp(pos, ttMove, rbeta - ss->staticEval, &thisThread->captureHistory); int probCutCount = 0; while ( (move = mp.next_move()) != MOVE_NONE - && probCutCount < depth / ONE_PLY - 3) + && probCutCount < 3) if (pos.legal(move)) { probCutCount++; @@ -778,15 +778,11 @@ namespace { pos.do_move(move, st); - // Perform a preliminary search at depth 1 to verify that the move holds. - // We will only do this search if the depth is not 5, thus avoiding two - // searches at depth 1 in a row. - if (depth != 5 * ONE_PLY) - value = -search(pos, ss+1, -rbeta, -rbeta+1, ONE_PLY, !cutNode, true); + // Perform a preliminary qsearch to verify that the move holds + value = -qsearch(pos, ss+1, -rbeta, -rbeta+1); - // If the first search was skipped or was performed and held, perform - // the regular search. - if (depth == 5 * ONE_PLY || value >= rbeta) + // If the qsearch held perform the regular search + if (value >= rbeta) value = -search(pos, ss+1, -rbeta, -rbeta+1, depth - 4 * ONE_PLY, !cutNode, false); pos.undo_move(move); @@ -1013,10 +1009,8 @@ moves_loop: // When in check, search starts from here // Step 17. Full depth search when LMR is skipped or fails high if (doFullDepthSearch) - value = newDepth < ONE_PLY ? - givesCheck ? -qsearch(pos, ss+1, -(alpha+1), -alpha) - : -qsearch(pos, ss+1, -(alpha+1), -alpha) - : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode, false); + value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -(alpha+1), -alpha) + : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode, false); // For PV nodes only, do a full PV search on the first move or after a fail // high (in the latter case search only if value < beta), otherwise let the @@ -1026,10 +1020,8 @@ moves_loop: // When in check, search starts from here (ss+1)->pv = pv; (ss+1)->pv[0] = MOVE_NONE; - value = newDepth < ONE_PLY ? - givesCheck ? -qsearch(pos, ss+1, -beta, -alpha) - : -qsearch(pos, ss+1, -beta, -alpha) - : - search(pos, ss+1, -beta, -alpha, newDepth, false, false); + value = newDepth < ONE_PLY ? -qsearch(pos, ss+1, -beta, -alpha) + : - search(pos, ss+1, -beta, -alpha, newDepth, false, false); } // Step 18. Undo move @@ -1158,17 +1150,16 @@ moves_loop: // When in check, search starts from here // qsearch() is the quiescence search function, which is called by the main // search function with depth zero, or recursively with depth less than ONE_PLY. - - template + template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { const bool PvNode = NT == PV; + const bool inCheck = bool(pos.checkers()); assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE); assert(PvNode || (alpha == beta - 1)); assert(depth <= DEPTH_ZERO); assert(depth / ONE_PLY * ONE_PLY == depth); - assert(InCheck == bool(pos.checkers())); Move pv[MAX_PLY+1]; StateInfo st; @@ -1194,14 +1185,14 @@ moves_loop: // When in check, search starts from here // Check for an immediate draw or maximum ply reached if ( pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) - return (ss->ply >= MAX_PLY && !InCheck) ? evaluate(pos) : VALUE_DRAW; + return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos) : VALUE_DRAW; assert(0 <= ss->ply && ss->ply < MAX_PLY); // Decide whether or not to include checks: this fixes also the type of // TT entry depth that we are going to use. Note that in qsearch we use // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS. - ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS + ttDepth = inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS; // Transposition table lookup posKey = pos.key(); @@ -1218,7 +1209,7 @@ moves_loop: // When in check, search starts from here return ttValue; // Evaluate the position statically - if (InCheck) + if (inCheck) { ss->staticEval = VALUE_NONE; bestValue = futilityBase = -VALUE_INFINITE; @@ -1273,7 +1264,7 @@ moves_loop: // When in check, search starts from here moveCount++; // Futility pruning - if ( !InCheck + if ( !inCheck && !givesCheck && futilityBase > -VALUE_KNOWN_WIN && !pos.advanced_pawn_push(move)) @@ -1296,13 +1287,13 @@ moves_loop: // When in check, search starts from here } // Detect non-capture evasions that are candidates to be pruned - evasionPrunable = InCheck + evasionPrunable = inCheck && (depth != DEPTH_ZERO || moveCount > 2) && bestValue > VALUE_MATED_IN_MAX_PLY && !pos.capture(move); // Don't search moves with negative SEE values - if ( (!InCheck || evasionPrunable) + if ( (!inCheck || evasionPrunable) && !pos.see_ge(move)) continue; @@ -1320,8 +1311,7 @@ moves_loop: // When in check, search starts from here // Make and search the move pos.do_move(move, st, givesCheck); - value = givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY) - : -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY); + value = -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY); pos.undo_move(move); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); @@ -1354,7 +1344,7 @@ moves_loop: // When in check, search starts from here // All legal moves have been searched. A special case: If we're in check // and no legal moves were found, it is checkmate. - if (InCheck && bestValue == -VALUE_INFINITE) + if (inCheck && bestValue == -VALUE_INFINITE) return mated_in(ss->ply); // Plies to mate from the root tte->save(posKey, value_to_tt(bestValue, ss->ply),