mirror of
https://github.com/sockspls/badfish
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a2f46446cf
Test by Joona prooves the new feature don't value 70 added lines of code. Grand totals after 10040 games (crashes: 0) for tt_both master_9edc7 - 6a93488_6a934: 1756 - 1688 - 6596 ELO +2 (+- 2.7) Confirmed by test of Gary: After 8680 games: ELO: 0.80 +- 99%: 9.62 95%: 7.31 LOS: 65.38% Wins: 1288 Losses: 1268 Draws: 6130 Thanks a lot to both for testing it !!! bench 5149248
141 lines
4.3 KiB
C++
141 lines
4.3 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) 2008-2012 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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#include <cstring>
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#include <iostream>
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#include "bitboard.h"
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#include "tt.h"
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TranspositionTable TT; // Our global transposition table
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TranspositionTable::TranspositionTable() {
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size = generation = 0;
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entries = NULL;
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}
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TranspositionTable::~TranspositionTable() {
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delete [] entries;
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}
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/// TranspositionTable::set_size() sets the size of the transposition table,
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/// measured in megabytes. Transposition table consists of a power of 2 number of
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/// TTCluster and each cluster consists of ClusterSize number of TTEntries. Each
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/// non-empty entry contains information of exactly one position.
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void TranspositionTable::set_size(size_t mbSize) {
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size_t newSize = 1ULL << msb((mbSize << 20) / sizeof(TTCluster));
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if (newSize == size)
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return;
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size = newSize;
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delete [] entries;
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entries = new (std::nothrow) TTCluster[size];
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if (!entries)
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{
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std::cerr << "Failed to allocate " << mbSize
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<< "MB for transposition table." << std::endl;
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exit(EXIT_FAILURE);
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}
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clear(); // Operator new is not guaranteed to initialize memory to zero
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}
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/// TranspositionTable::clear() overwrites the entire transposition table
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/// with zeroes. It is called whenever the table is resized, or when the
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/// user asks the program to clear the table (from the UCI interface).
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void TranspositionTable::clear() {
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memset(entries, 0, size * sizeof(TTCluster));
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}
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/// TranspositionTable::store() writes a new entry containing position key and
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/// valuable information of current position. The lowest order bits of position
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/// key are used to decide on which cluster the position will be placed.
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/// When a new entry is written and there are no empty entries available in cluster,
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/// it replaces the least valuable of entries. A TTEntry t1 is considered to be
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/// more valuable than a TTEntry t2 if t1 is from the current search and t2 is from
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/// a previous search, or if the depth of t1 is bigger than the depth of t2.
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void TranspositionTable::store(const Key posKey, Value v, Bound t, Depth d, Move m) {
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int c1, c2, c3;
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TTEntry *tte, *replace;
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uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key inside the cluster
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tte = replace = first_entry(posKey);
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for (int i = 0; i < ClusterSize; i++, tte++)
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{
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if (!tte->key() || tte->key() == posKey32) // Empty or overwrite old
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{
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// Preserve any existing ttMove
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if (m == MOVE_NONE)
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m = tte->move();
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tte->save(posKey32, v, t, d, m, generation);
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return;
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}
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// Implement replace strategy
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c1 = (replace->generation() == generation ? 2 : 0);
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c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0);
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c3 = (tte->depth() < replace->depth() ? 1 : 0);
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if (c1 + c2 + c3 > 0)
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replace = tte;
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}
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replace->save(posKey32, v, t, d, m, generation);
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}
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/// TranspositionTable::probe() looks up the current position in the
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/// transposition table. Returns a pointer to the TTEntry or NULL if
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/// position is not found.
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TTEntry* TranspositionTable::probe(const Key posKey) const {
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uint32_t posKey32 = posKey >> 32;
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TTEntry* tte = first_entry(posKey);
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for (int i = 0; i < ClusterSize; i++, tte++)
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if (tte->key() == posKey32)
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return tte;
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return NULL;
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}
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/// TranspositionTable::new_search() is called at the beginning of every new
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/// search. It increments the "generation" variable, which is used to
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/// distinguish transposition table entries from previous searches from
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/// entries from the current search.
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void TranspositionTable::new_search() {
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generation++;
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}
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