X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=375c00a67308fbc934e7cad2fe569f5a780468f3;hp=268c21f896ab3c89e962ae6dde36c9001030231b;hb=9ca4359f3691305fc5e3306c3084c83557ce09c0;hpb=c2c0ba875f429e497c936b61be9f75dcc88385a9 diff --git a/src/tt.cpp b/src/tt.cpp index 268c21f8..375c00a6 100644 --- a/src/tt.cpp +++ b/src/tt.cpp @@ -1,13 +1,14 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad - Glaurung is free software: you can redistribute it and/or modify + Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - Glaurung is distributed in the hope that it will be useful, + Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. @@ -22,29 +23,24 @@ //// #include -#include +#include #include "tt.h" +// The main transposition table +TranspositionTable TT; //// //// Functions //// -/// Constructor - -TranspositionTable::TranspositionTable(unsigned mbSize) { +TranspositionTable::TranspositionTable() { size = 0; - generation = 0; - writes = 0; entries = 0; - set_size(mbSize); + generation = 0; } - -/// Destructor - TranspositionTable::~TranspositionTable() { delete [] entries; @@ -54,196 +50,109 @@ TranspositionTable::~TranspositionTable() { /// TranspositionTable::set_size sets the size of the transposition table, /// measured in megabytes. -void TranspositionTable::set_size(unsigned mbSize) { +void TranspositionTable::set_size(size_t mbSize) { - assert(mbSize >= 4 && mbSize <= 1024); + size_t newSize = 1024; - unsigned newSize = 1024; + // Transposition table consists of clusters and + // each cluster consists of ClusterSize number of TTEntries. + // Each non-empty entry contains information of exactly one position. + // newSize is the number of clusters we are going to allocate. + while ((2 * newSize) * sizeof(TTCluster) <= (mbSize << 20)) + newSize *= 2; - // We store a cluster of 4 TTEntry for each position and newSize is - // the maximum number of storable positions - for ( ; newSize * 4 * (sizeof(TTEntry)) <= (mbSize << 20); newSize *= 2); - newSize /= 2; if (newSize != size) { - size = newSize; - delete [] entries; - entries = new TTEntry[size * 4]; - if (!entries) - { - std::cerr << "Failed to allocate " << mbSize - << " MB for transposition table." - << std::endl; - exit(EXIT_FAILURE); - } - clear(); + size = newSize; + delete [] entries; + entries = new TTCluster[size]; + if (!entries) + { + std::cerr << "Failed to allocate " << mbSize + << " MB for transposition table." << std::endl; + Application::exit_with_failure(); + } + clear(); } } /// TranspositionTable::clear overwrites the entire transposition table -/// with zeroes. It is called whenever the table is resized, or when the +/// with zeroes. It is called whenever the table is resized, or when the /// user asks the program to clear the table (from the UCI interface). -/// Perhaps we should also clear it when the "ucinewgame" command is recieved? +/// Perhaps we should also clear it when the "ucinewgame" command is received? void TranspositionTable::clear() { - memset(entries, 0, size * 4 * sizeof(TTEntry)); + memset(entries, 0, size * sizeof(TTCluster)); } -/// TranspositionTable::store writes a new entry containing a position, -/// a value, a value type, a search depth, and a best move to the -/// transposition table. The transposition table is organized in clusters -/// of four TTEntry objects, and when a new entry is written, it replaces -/// the least valuable of the four entries in a cluster. A TTEntry t1 is -/// considered to be more valuable than a TTEntry t2 if t1 is from the +/// TranspositionTable::store writes a new entry containing position key and +/// valuable information of current position. +/// The Lowest order bits of position key are used to decide on which cluster +/// the position will be placed. +/// When a new entry is written and there are no empty entries available in cluster, +/// it replaces the least valuable of entries. +/// A TTEntry t1 is considered to be more valuable than a TTEntry t2 if t1 is from the /// current search and t2 is from a previous search, or if the depth of t1 /// is bigger than the depth of t2. -void TranspositionTable::store(const Position &pos, Value v, Depth d, - Move m, ValueType type) { +void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m, Value statV, Value kingD) { + + int c1, c2, c3; TTEntry *tte, *replace; + uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key - tte = replace = first_entry(pos); - for (int i = 0; i < 4; i++) + tte = replace = first_entry(posKey); + for (int i = 0; i < ClusterSize; i++, tte++) { - if (!(tte+i)->key()) // still empty - { - *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation); - writes++; - return; - } - if ((tte+i)->key() == pos.get_key()) // overwrite old - { - if (m == MOVE_NONE) - m = (tte+i)->move(); - - *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation); - return; - } - if ( i == 0 // already is (replace == tte+i), common case - || replace->generation() < (tte+i)->generation()) - continue; - - if ( replace->generation() > (tte+i)->generation() - || (tte+i)->depth() < replace->depth()) - replace = tte+i; - } - *replace = TTEntry(pos.get_key(), v, type, d, m, generation); - writes++; -} + if (!tte->key() || tte->key() == posKey32) // empty or overwrite old + { + // Preserve any existing ttMove + if (m == MOVE_NONE) + m = tte->move(); + tte->save(posKey32, v, t, d, m, generation, statV, kingD); + return; + } -/// TranspositionTable::retrieve looks up the current position in the -/// transposition table, and extracts the value, value type, depth and -/// best move if the position is found. The return value is true if -/// the position is found, and false if it isn't. + if (i == 0) // Replacing first entry is default and already set before entering for-loop + continue; -bool TranspositionTable::retrieve(const Position &pos, Value *value, - Depth *d, Move *move, - ValueType *type) const { - TTEntry *tte = first_entry(pos); + c1 = (replace->generation() == generation ? 2 : 0); + c2 = (tte->generation() == generation ? -2 : 0); + c3 = (tte->depth() < replace->depth() ? 1 : 0); - for (int i = 0; i < 4; i++) - { - tte += i; - if (tte->key() == pos.get_key()) - { - *value = tte->value(); - *type = tte->type(); - *d = tte->depth(); - *move = tte->move(); - return true; - } + if (c1 + c2 + c3 > 0) + replace = tte; } - *move = MOVE_NONE; - return false; + replace->save(posKey32, v, t, d, m, generation, statV, kingD); } -/// TranspositionTable::first_entry returns a pointer to the first -/// entry of a cluster given a position. +/// TranspositionTable::retrieve looks up the current position in the +/// transposition table. Returns a pointer to the TTEntry or NULL +/// if position is not found. + +TTEntry* TranspositionTable::retrieve(const Key posKey) const { -inline TTEntry* TranspositionTable::first_entry(const Position &pos) const { + uint32_t posKey32 = posKey >> 32; + TTEntry* tte = first_entry(posKey); - return entries + (int(pos.get_key() & (size - 1)) << 2); + for (int i = 0; i < ClusterSize; i++, tte++) + if (tte->key() == posKey32) + return tte; + + return NULL; } + /// TranspositionTable::new_search() is called at the beginning of every new -/// search. It increments the "generation" variable, which is used to +/// search. It increments the "generation" variable, which is used to /// distinguish transposition table entries from previous searches from /// entries from the current search. void TranspositionTable::new_search() { - generation++; - writes = 0; -} - - -/// TranspositionTable::insert_pv() is called at the end of a search -/// iteration, and inserts the PV back into the PV. This makes sure the -/// old PV moves are searched first, even if the old TT entries have been -/// overwritten. - -void TranspositionTable::insert_pv(const Position &pos, Move pv[]) { - - UndoInfo u; - Position p(pos); - - for (int i = 0; pv[i] != MOVE_NONE; i++) - { - store(p, VALUE_NONE, Depth(0), pv[i], VALUE_TYPE_NONE); - p.do_move(pv[i], u); - } -} - - -/// TranspositionTable::full() returns the permill of all transposition table -/// entries which have received at least one write during the current search. -/// It is used to display the "info hashfull ..." information in UCI. - -int TranspositionTable::full() { - - double N = double(size) * 4.0; - return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N)))); -} - - -/// Constructors - -TTEntry::TTEntry() { -} - -TTEntry::TTEntry(Key k, Value v, ValueType t, Depth d, Move m, - int generation) : - key_ (k), data((m & 0x7FFFF) | (t << 20) | (generation << 23)), - value_(v), depth_(int16_t(d)) {} - - -/// Functions for extracting data from TTEntry objects. - -inline Key TTEntry::key() const { - return key_; -} - -inline Depth TTEntry::depth() const { - return Depth(depth_); -} - -inline Move TTEntry::move() const { - return Move(data & 0x7FFFF); -} - -inline Value TTEntry::value() const { - return Value(value_); -} - -inline ValueType TTEntry::type() const { - return ValueType((data >> 20) & 3); -} - -inline int TTEntry::generation() const { - return (data >> 23); }