2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
5 Stockfish is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 Stockfish is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
24 #include "../search.h"
26 namespace Stockfish::Tablebases {
30 WDLBlessedLoss = -1, // Loss, but draw under 50-move rule
32 WDLCursedWin = 1, // Win, but draw under 50-move rule
38 // Possible states after a probing operation
40 FAIL = 0, // Probe failed (missing file table)
41 OK = 1, // Probe succesful
42 CHANGE_STM = -1, // DTZ should check the other side
43 ZEROING_BEST_MOVE = 2 // Best move zeroes DTZ (capture or pawn move)
46 extern int MaxCardinality;
48 void init(const std::string& paths);
49 WDLScore probe_wdl(Position& pos, ProbeState* result);
50 int probe_dtz(Position& pos, ProbeState* result);
51 bool root_probe(Position& pos, Search::RootMoves& rootMoves);
52 bool root_probe_wdl(Position& pos, Search::RootMoves& rootMoves);
53 void rank_root_moves(Position& pos, Search::RootMoves& rootMoves);
55 inline std::ostream& operator<<(std::ostream& os, const WDLScore v) {
57 os << (v == WDLLoss ? "Loss" :
58 v == WDLBlessedLoss ? "Blessed loss" :
59 v == WDLDraw ? "Draw" :
60 v == WDLCursedWin ? "Cursed win" :
61 v == WDLWin ? "Win" : "None");
66 inline std::ostream& operator<<(std::ostream& os, const ProbeState v) {
68 os << (v == FAIL ? "Failed" :
70 v == CHANGE_STM ? "Probed opponent side" :
71 v == ZEROING_BEST_MOVE ? "Best move zeroes DTZ" : "None");
76 } // namespace Stockfish::Tablebases