mirror of
https://github.com/official-stockfish/Stockfish.git
synced 2026-07-23 13:17:12 +00:00
Lucas BraeschandMarco Costalba
eed508b444
1/ eval margin and gains removed: 16bit are now free on TT entries, due to the removal of eval margin. may be useful in the future :) gains removed: use instead by Value(128). search() and qsearch() are now consistent in this regard. 2/ futility_margin() linear formula instead of complex (log(depth), movecount) formula. 3/ unify pre & post futility pruning pre futility pruning used depth < 7 plies, while post futility pruning used depth < 4 plies. Now it's always depth < 7. Tested with fixed number of games both at short TC: ELO: 0.82 +-2.1 (95%) LOS: 77.3% Total: 40000 W: 7939 L: 7845 D: 24216 And long TC ELO: 0.59 +-2.0 (95%) LOS: 71.9% Total: 40000 W: 6876 L: 6808 D: 26316 bench 7243575
117 lines
3.5 KiB
C++
117 lines
3.5 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef TT_H_INCLUDED
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#define TT_H_INCLUDED
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#include "misc.h"
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#include "types.h"
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/// The TTEntry is the 128 bit transposition table entry, defined as below:
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///
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/// key: 32 bit
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/// move: 16 bit
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/// bound type: 8 bit
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/// generation: 8 bit
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/// value: 16 bit
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/// depth: 16 bit
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/// static value: 16 bit
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/// static margin: 16 bit
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struct TTEntry {
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void save(uint32_t k, Value v, Bound b, Depth d, Move m, int g, Value ev) {
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key32 = (uint32_t)k;
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move16 = (uint16_t)m;
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bound8 = (uint8_t)b;
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generation8 = (uint8_t)g;
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value16 = (int16_t)v;
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depth16 = (int16_t)d;
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evalValue = (int16_t)ev;
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}
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void set_generation(uint8_t g) { generation8 = g; }
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uint32_t key() const { return key32; }
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Depth depth() const { return (Depth)depth16; }
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Move move() const { return (Move)move16; }
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Value value() const { return (Value)value16; }
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Bound bound() const { return (Bound)bound8; }
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int generation() const { return (int)generation8; }
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Value eval_value() const { return (Value)evalValue; }
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private:
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uint32_t key32;
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uint16_t move16;
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uint8_t bound8, generation8;
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int16_t value16, depth16, evalValue;
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};
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/// A TranspositionTable consists of a power of 2 number of clusters and each
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/// cluster consists of ClusterSize number of TTEntry. Each non-empty entry
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/// contains information of exactly one position. Size of a cluster shall not be
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/// bigger than a cache line size. In case it is less, it should be padded to
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/// guarantee always aligned accesses.
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class TranspositionTable {
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static const unsigned ClusterSize = 4; // A cluster is 64 Bytes
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public:
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~TranspositionTable() { free(mem); }
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void new_search() { ++generation; }
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const TTEntry* probe(const Key key) const;
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TTEntry* first_entry(const Key key) const;
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void refresh(const TTEntry* tte) const;
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void set_size(size_t mbSize);
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void clear();
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void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
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private:
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uint32_t hashMask;
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TTEntry* table;
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void* mem;
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uint8_t generation; // Size must be not bigger than TTEntry::generation8
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};
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extern TranspositionTable TT;
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/// TranspositionTable::first_entry() returns a pointer to the first entry of
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/// a cluster given a position. The lowest order bits of the key are used to
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/// get the index of the cluster.
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inline TTEntry* TranspositionTable::first_entry(const Key key) const {
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return table + ((uint32_t)key & hashMask);
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}
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/// TranspositionTable::refresh() updates the 'generation' value of the TTEntry
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/// to avoid aging. Normally called after a TT hit.
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inline void TranspositionTable::refresh(const TTEntry* tte) const {
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const_cast<TTEntry*>(tte)->set_generation(generation);
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}
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#endif // #ifndef TT_H_INCLUDED
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