X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=e9b6c1758c7eb5c7ead2bae915fccd2e7bc243ab;hp=5c842db85ea3a552a03cae2bf03a04199003bb39;hb=e6863f46de3eea91a1093465959f1acd75d6d02c;hpb=9e44a6dba9718b74a64656ae7801a62946c3b725 diff --git a/src/tt.cpp b/src/tt.cpp index 5c842db8..e9b6c175 100644 --- a/src/tt.cpp +++ b/src/tt.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008 Marco Costalba + Copyright (C) 2008-2009 Marco Costalba Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -26,27 +26,25 @@ #include #include +#include "movegen.h" #include "tt.h" +/// This is the number of TTEntry slots for each position +static const int ClusterSize = 5; + + //// //// Functions //// -/// Constructor +TranspositionTable::TranspositionTable() { -TranspositionTable::TranspositionTable(unsigned mbSize) { - - size = 0; - generation = 0; - writes = 0; + size = writes = 0; entries = 0; - set_size(mbSize); + generation = 0; } - -/// Destructor - TranspositionTable::~TranspositionTable() { delete [] entries; @@ -58,77 +56,83 @@ TranspositionTable::~TranspositionTable() { void TranspositionTable::set_size(unsigned mbSize) { - assert(mbSize >= 4 && mbSize <= 1024); + assert(mbSize >= 4 && mbSize <= 4096); unsigned newSize = 1024; - // 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; + // We store a cluster of ClusterSize number of TTEntry for each position + // and newSize is the maximum number of storable positions. + while ((2 * newSize) * ClusterSize * (sizeof(TTEntry)) <= (mbSize << 20)) + 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 TTEntry[size * ClusterSize]; + 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? void TranspositionTable::clear() { - memset(entries, 0, size * 4 * sizeof(TTEntry)); + memset(entries, 0, size * ClusterSize * sizeof(TTEntry)); } /// 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 +/// transposition table. 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 /// current search and t2 is from a previous search, or if the depth of t1 -/// is bigger than the depth of t2. +/// is bigger than the depth of t2. A TTEntry of type VALUE_TYPE_EVAL +/// never replaces another entry for the same position. + +void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m) { -void TranspositionTable::store(const Position &pos, Value v, Depth d, - Move m, ValueType type) { 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++) + tte = replace = first_entry(posKey); + for (int i = 0; i < ClusterSize; i++, tte++) { - if (!tte->key() || tte->key() == pos.get_key()) // empty or overwrite old - { - if (m == MOVE_NONE) - m = tte->move(); - - *tte = TTEntry(pos.get_key(), v, type, d, m, generation); - return; - } - else if (i == 0) // replace would be a no-op in this common case - continue; - - int c1 = (replace->generation() == generation ? 2 : 0); - int c2 = (tte->generation() == generation ? -2 : 0); - int c3 = (tte->depth() < replace->depth() ? 1 : 0); - - if (c1 + c2 + c3 > 0) - replace = tte; + if (!tte->key() || tte->key() == posKey32) // empty or overwrite old + { + // Do not overwrite when new type is VALUE_TYPE_EVAL + if (tte->key() && t == VALUE_TYPE_EVAL) + return; + + if (m == MOVE_NONE) + m = tte->move(); + + *tte = TTEntry(posKey32, v, t, d, m, generation); + return; + } + else if (i == 0) // replace would be a no-op in this common case + continue; + + int c1 = (replace->generation() == generation ? 2 : 0); + int c2 = (tte->generation() == generation ? -2 : 0); + int c3 = (tte->depth() < replace->depth() ? 1 : 0); + + if (c1 + c2 + c3 > 0) + replace = tte; } - *replace = TTEntry(pos.get_key(), v, type, d, m, generation); + *replace = TTEntry(posKey32, v, t, d, m, generation); writes++; } @@ -137,29 +141,30 @@ void TranspositionTable::store(const Position &pos, Value v, Depth d, /// transposition table. Returns a pointer to the TTEntry or NULL /// if position is not found. -TTEntry* TranspositionTable::retrieve(const Position &pos) const { +TTEntry* TranspositionTable::retrieve(const Key posKey) const { - TTEntry *tte = first_entry(pos); + uint32_t posKey32 = posKey >> 32; + TTEntry *tte = first_entry(posKey); - for (int i = 0; i < 4; i++, tte++) - { - if (tte->key() == pos.get_key()) + for (int i = 0; i < ClusterSize; i++, tte++) + if (tte->key() == posKey32) return tte; - } + return NULL; } /// TranspositionTable::first_entry returns a pointer to the first -/// entry of a cluster given a position. +/// entry of a cluster given a position. The low 32 bits of the key +/// are used to get the index in the table. -inline TTEntry* TranspositionTable::first_entry(const Position &pos) const { +inline TTEntry* TranspositionTable::first_entry(const Key posKey) const { - return entries + (int(pos.get_key() & (size - 1)) << 2); + return entries + ((uint32_t(posKey) & (size - 1)) * ClusterSize); } /// 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. @@ -171,40 +176,61 @@ void TranspositionTable::new_search() { /// 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. +/// 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[]) { +void TranspositionTable::insert_pv(const Position& pos, Move pv[]) { StateInfo st; Position p(pos); for (int i = 0; pv[i] != MOVE_NONE; i++) { - store(p, VALUE_NONE, Depth(-127*OnePly), pv[i], VALUE_TYPE_NONE); - p.do_move(pv[i], st); + store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]); + p.do_move(pv[i], st); } } -/// 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. +/// TranspositionTable::extract_pv() extends a PV by adding moves from the +/// transposition table at the end. This should ensure that the PV is almost +/// always at least two plies long, which is important, because otherwise we +/// will often get single-move PVs when the search stops while failing high, +/// and a single-move PV means that we don't have a ponder move. -int TranspositionTable::full() { +void TranspositionTable::extract_pv(const Position& pos, Move pv[]) { - double N = double(size) * 4.0; - return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N)))); + int ply; + Position p(pos); + StateInfo st[100]; + + for (ply = 0; pv[ply] != MOVE_NONE; ply++) + p.do_move(pv[ply], st[ply]); + + bool stop; + const TTEntry* tte; + for (stop = false, tte = retrieve(p.get_key()); + tte && tte->move() != MOVE_NONE && !stop; + tte = retrieve(p.get_key()), ply++) + { + if (!move_is_legal(p, tte->move())) + break; + pv[ply] = tte->move(); + p.do_move(pv[ply], st[ply]); + for (int j = 0; j < ply; j++) + if (st[j].key == p.get_key()) stop = true; + } + pv[ply] = MOVE_NONE; } -/// Constructors +/// 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. -TTEntry::TTEntry() { -} +int TranspositionTable::full() const { -TTEntry::TTEntry(Key k, Value v, ValueType t, Depth d, Move m, - int generation) : - key_ (k), data((m & 0x1FFFF) | (t << 20) | (generation << 23)), - value_(int16_t(v)), depth_(int16_t(d)) {} + double N = double(size) * ClusterSize; + return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N)))); +}