X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=13f333d9fc5a95511f133ee15f5d0a681e095f16;hp=d2e3cd32caef87b97a523d53708532de0c9a0c71;hb=57340c109b0ddd8764bf73dfa3bfe2bbe7928b59;hpb=01b228b5e179d2e15927d617c5415302be234e3f diff --git a/src/search.cpp b/src/search.cpp index d2e3cd32..13f333d9 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -162,7 +162,10 @@ namespace { // Step 6. Razoring + // Maximum depth for razoring const Depth RazorDepth = 4 * OnePly; + + // Dynamic razoring margin based on depth inline Value razor_margin(Depth d) { return Value(0x200 + 0x10 * d); } // Step 8. Null move search with verification search @@ -171,8 +174,12 @@ namespace { // evaluation of the position is more than NullMoveMargin below beta. const Value NullMoveMargin = Value(0x200); + // Maximum depth for use of dynamic threat detection when null move fails low + const Depth ThreatDepth = 5 * OnePly; + // Step 9. Internal iterative deepening + // Minimum depth for use of internal iterative deepening const Depth IIDDepthAtPVNodes = 5 * OnePly; const Depth IIDDepthAtNonPVNodes = 8 * OnePly; @@ -181,38 +188,50 @@ namespace { // search when the static evaluation is at most IIDMargin below beta. const Value IIDMargin = Value(0x100); - // Search depth at iteration 1 - const Depth InitialDepth = OnePly; + // Step 11. Decide the new search depth - // Easy move margin. An easy move candidate must be at least this much - // better than the second best move. - const Value EasyMoveMargin = Value(0x200); - - // If the TT move is at least SingleReplyMargin better then the - // remaining ones we will extend it. - const Value SingleReplyMargin = Value(0x20); + // Extensions. Configurable UCI options. + // Array index 0 is used at non-PV nodes, index 1 at PV nodes. + Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2]; + Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; - /// Lookup tables initialized at startup + // Minimum depth for use of singular extension + const Depth SingularExtensionDepthAtPVNodes = 6 * OnePly; + const Depth SingularExtensionDepthAtNonPVNodes = 8 * OnePly; - // Reduction lookup tables and their getter functions - int8_t PVReductionMatrix[64][64]; // [depth][moveNumber] - int8_t NonPVReductionMatrix[64][64]; // [depth][moveNumber] + // If the TT move is at least SingularExtensionMargin better then the + // remaining ones we will extend it. + const Value SingularExtensionMargin = Value(0x20); - inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } - inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } + // Step 12. Futility pruning - // Futility lookup tables and their getter functions + // Futility margin for quiescence search const Value FutilityMarginQS = Value(0x80); + + // Futility lookup tables (initialized at startup) and their getter functions int32_t FutilityMarginsMatrix[14][64]; // [depth][moveNumber] int FutilityMoveCountArray[32]; // [depth] inline Value futility_margin(Depth d, int mn) { return Value(d < 7*OnePly ? FutilityMarginsMatrix[Max(d, 0)][Min(mn, 63)] : 2 * VALUE_INFINITE); } inline int futility_move_count(Depth d) { return d < 16*OnePly ? FutilityMoveCountArray[d] : 512; } - /// Variables initialized by UCI options + // Step 14. Reduced search + + // Reduction lookup tables (initialized at startup) and their getter functions + int8_t PVReductionMatrix[64][64]; // [depth][moveNumber] + int8_t NonPVReductionMatrix[64][64]; // [depth][moveNumber] + + inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } + inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } + + // Step. Common adjustments + + // Search depth at iteration 1 + const Depth InitialDepth = OnePly; - // Depth limit for use of dynamic threat detection - Depth ThreatDepth; + // Easy move margin. An easy move candidate must be at least this much + // better than the second best move. + const Value EasyMoveMargin = Value(0x200); // Last seconds noise filtering (LSN) const bool UseLSNFiltering = true; @@ -220,9 +239,8 @@ namespace { const Value LSNValue = value_from_centipawns(200); bool loseOnTime = false; - // Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes. - Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2]; - Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; + + /// Global variables // Iteration counters int Iteration; @@ -418,8 +436,6 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, MateThreatExtension[1] = Depth(get_option_value_int("Mate Threat Extension (PV nodes)")); MateThreatExtension[0] = Depth(get_option_value_int("Mate Threat Extension (non-PV nodes)")); - ThreatDepth = get_option_value_int("Threat Depth") * OnePly; - Chess960 = get_option_value_bool("UCI_Chess960"); ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine"); UseLogFile = get_option_value_bool("Use Search Log"); @@ -1133,7 +1149,7 @@ namespace { // Singular extension search. We extend the TT move if its value is much better than // its siblings. To verify this we do a reduced search on all the other moves but the // ttMove, if result is lower then ttValue minus a margin then we extend ttMove. - if ( depth >= 6 * OnePly + if ( depth >= SingularExtensionDepthAtPVNodes && tte && move == tte->move() && ext < OnePly @@ -1144,9 +1160,9 @@ namespace { if (abs(ttValue) < VALUE_KNOWN_WIN) { - Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move); + Value excValue = search(pos, ss, ttValue - SingularExtensionMargin, depth / 2, ply, false, threadID, move); - if (excValue < ttValue - SingleReplyMargin) + if (excValue < ttValue - SingularExtensionMargin) ext = OnePly; } } @@ -1446,7 +1462,7 @@ namespace { // Singular extension search. We extend the TT move if its value is much better than // its siblings. To verify this we do a reduced search on all the other moves but the // ttMove, if result is lower then ttValue minus a margin then we extend ttMove. - if ( depth >= 8 * OnePly + if ( depth >= SingularExtensionDepthAtNonPVNodes && tte && move == tte->move() && !excludedMove // Do not allow recursive single-reply search @@ -1458,9 +1474,9 @@ namespace { if (abs(ttValue) < VALUE_KNOWN_WIN) { - Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move); + Value excValue = search(pos, ss, ttValue - SingularExtensionMargin, depth / 2, ply, false, threadID, move); - if (excValue < ttValue - SingleReplyMargin) + if (excValue < ttValue - SingularExtensionMargin) ext = OnePly; } } @@ -1484,7 +1500,7 @@ namespace { continue; // Value based pruning - Depth predictedDepth = newDepth - nonpv_reduction(depth, moveCount); //FIXME: We are ignoring condition: depth >= 3*OnePly, BUG?? + Depth predictedDepth = newDepth - nonpv_reduction(depth, moveCount); // We illogically ignore reduction condition depth >= 3*OnePly futilityValueScaled = ss[ply].eval + futility_margin(predictedDepth, moveCount) + H.gain(pos.piece_on(move_from(move)), move_to(move)) + 45; @@ -2752,9 +2768,6 @@ namespace { cout << "Failed to create thread number " << i << endl; Application::exit_with_failure(); } - - // Wait until the thread has finished launching and is gone to sleep - while (threads[i].state != THREAD_SLEEPING); } } @@ -2983,9 +2996,6 @@ namespace { if (ActiveThreads == 1) return; - for (int i = 1; i < ActiveThreads; i++) - assert(threads[i].state == THREAD_SLEEPING); - #if !defined(_MSC_VER) pthread_mutex_lock(&WaitLock); pthread_cond_broadcast(&WaitCond);