X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=b86693289c8b2688070e74382a1b64c286528af2;hp=7ffdadcf9c96d8e82e4665fb02b2fa8232f23fa6;hb=c7a77dd3c01564c5d4bcd8029a1a48e18356df35;hpb=ae6157fcf33f840361acb24f98ea37299b3eaa36 diff --git a/src/search.cpp b/src/search.cpp index 7ffdadcf..b8669328 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -180,12 +180,8 @@ namespace { const Value FutilityMarginQS = Value(0x80); // Each move futility margin is decreased - const Value IncrementalFutilityMargin = Value(0x8); + const Value IncrementalFutilityMargin = Value(0x4); - // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply - const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270), - // 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply - Value(0x2A0), Value(0x2C0), Value(0x340), Value(0x360), Value(0x3A0), Value(0x3C0) }; // Razoring const Depth RazorDepth = 4*OnePly; @@ -1169,7 +1165,7 @@ namespace { // To verify this we do a reduced search on all the other moves but the ttMove, // if result is lower then TT value minus a margin then we assume ttMove is the // only one playable. It is a kind of relaxed single reply extension. - if ( depth >= 8 * OnePly + if ( depth >= 6 * OnePly && tte && move == tte->move() && ext < OnePly @@ -1180,7 +1176,7 @@ namespace { if (abs(ttValue) < VALUE_KNOWN_WIN) { - Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, ttMove); + Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move); // If search result is well below the foreseen score of the ttMove then we // assume ttMove is the only one realistically playable and we extend it. @@ -1359,7 +1355,7 @@ namespace { if (tte && ok_to_use_TT(tte, depth, beta, ply)) { - ss[ply].currentMove = ttMove; // can be MOVE_NONE + ss[ply].currentMove = ttMove; // Can be MOVE_NONE return value_from_tt(tte->value(), ply); } @@ -1445,12 +1441,13 @@ namespace { futilityValue = VALUE_NONE; useFutilityPruning = depth < SelectiveDepth && !isCheck; + // Calculate depth dependant futility pruning parameters + const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8)); + const int FutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2); + // Avoid calling evaluate() if we already have the score in TT if (tte && (tte->type() & VALUE_TYPE_EVAL)) - futilityValue = value_from_tt(tte->value(), ply) + FutilityMargins[int(depth) - 2]; - - // Move count pruning limit - const int MCLimit = 3 + (1 << (3*int(depth)/8)); + futilityValue = value_from_tt(tte->value(), ply) + FutilityValueMargin; // Loop through all legal moves until no moves remain or a beta cutoff occurs while ( bestValue < beta @@ -1485,7 +1482,7 @@ namespace { if (abs(ttValue) < VALUE_KNOWN_WIN) { - Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, ttMove); + Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move); // If search result is well below the foreseen score of the ttMove then we // assume ttMove is the only one realistically playable and we extend it. @@ -1506,7 +1503,7 @@ namespace { && move != ttMove) { // History pruning. See ok_to_prune() definition - if ( moveCount >= MCLimit + if ( moveCount >= FutilityMoveCountMargin && ok_to_prune(pos, move, ss[ply].threatMove, depth) && bestValue > value_mated_in(PLY_MAX)) continue; @@ -1515,8 +1512,7 @@ namespace { if (approximateEval < beta) { if (futilityValue == VALUE_NONE) - futilityValue = evaluate(pos, ei, threadID) - + 64*(2+bitScanReverse32(int(depth) * int(depth))); + futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin; futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin; @@ -1545,7 +1541,7 @@ namespace { value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID); } else - value = beta; // Just to trigger next condition + value = beta; // Just to trigger next condition if (value >= beta) // Go with full depth non-pv search { @@ -1559,12 +1555,12 @@ namespace { // New best move? if (value > bestValue) { - bestValue = value; - if (value >= beta) - update_pv(ss, ply); + bestValue = value; + if (value >= beta) + update_pv(ss, ply); - if (value == value_mate_in(ply + 1)) - ss[ply].mateKiller = move; + if (value == value_mate_in(ply + 1)) + ss[ply].mateKiller = move; } // Split? @@ -1577,7 +1573,7 @@ namespace { && !thread_should_stop(threadID) && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval, depth, &moveCount, &mp, threadID, false)) - break; + break; } // All legal moves have been searched. A special case: If there were @@ -1656,10 +1652,10 @@ namespace { } ttMove = (tte ? tte->move() : MOVE_NONE); - // Evaluate the position statically isCheck = pos.is_check(); ei.futilityMargin = Value(0); // Manually initialize futilityMargin + // Evaluate the position statically if (isCheck) staticValue = -VALUE_INFINITE; @@ -1668,7 +1664,7 @@ namespace { // Use the cached evaluation score if possible assert(ei.futilityMargin == Value(0)); - staticValue = tte->value(); + staticValue = value_from_tt(tte->value(), ply); } else staticValue = evaluate(pos, ei, threadID); @@ -1813,6 +1809,8 @@ namespace { bool useFutilityPruning = sp->depth < SelectiveDepth && !isCheck; + const int FutilityValueMargin = 112 * bitScanReverse32(int(sp->depth) * int(sp->depth) / 2); + while ( sp->bestValue < sp->beta && !thread_should_stop(threadID) && (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE) @@ -1850,8 +1848,7 @@ namespace { if (sp->futilityValue == VALUE_NONE) { EvalInfo ei; - sp->futilityValue = evaluate(pos, ei, threadID) - + FutilityMargins[int(sp->depth) - 2]; + sp->futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin; } if (sp->futilityValue < sp->beta)