X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=9dbfcb5ac92e5fada772fd8c20a74a4a41921c63;hp=c1a8b1b950b24edbc514fdb43baaae2dc6909288;hb=55df3fa2d7631ed67e46f9433aa7f3a71c18e5e7;hpb=2fff532f4e80c8e2e61d8b3955447f13124d40f0
diff --git a/src/tt.cpp b/src/tt.cpp
index c1a8b1b9..9dbfcb5a 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) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -17,28 +17,18 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
-#include
-#include
#include
+#include
-#include "movegen.h"
+#include "bitboard.h"
#include "tt.h"
-
-////
-//// Functions
-////
+TranspositionTable TT; // Our global transposition table
TranspositionTable::TranspositionTable() {
- size = writes = 0;
- entries = 0;
- generation = 0;
+ size = generation = 0;
+ entries = NULL;
}
TranspositionTable::~TranspositionTable() {
@@ -47,183 +37,105 @@ TranspositionTable::~TranspositionTable() {
}
-/// TranspositionTable::set_size sets the size of the transposition table,
-/// measured in megabytes.
+/// TranspositionTable::set_size() sets the size of the transposition table,
+/// measured in megabytes. Transposition table consists of a power of 2 number of
+/// TTCluster and each cluster consists of ClusterSize number of TTEntries. Each
+/// non-empty entry contains information of exactly one position.
-void TranspositionTable::set_size(unsigned mbSize) {
+void TranspositionTable::set_size(size_t mbSize) {
- assert(mbSize >= 4 && mbSize <= 4096);
+ size_t newSize = 1ULL << msb((mbSize << 20) / sizeof(TTCluster));
- unsigned newSize = 1024;
+ if (newSize == size)
+ return;
- // We store a cluster of 4 TTEntry for each position and newSize is
- // the maximum number of storable positions
- while ((2 * newSize) * 4 * (sizeof(TTEntry)) <= (mbSize << 20))
- newSize *= 2;
+ size = newSize;
+ delete [] entries;
+ entries = new (std::nothrow) TTCluster[size];
- if (newSize != size)
+ if (!entries)
{
- size = newSize;
- delete [] entries;
- entries = new TTEntry[size * 4];
- if (!entries)
- {
- std::cerr << "Failed to allocate " << mbSize
- << " MB for transposition table." << std::endl;
- Application::exit_with_failure();
- }
- clear();
+ std::cerr << "Failed to allocate " << mbSize
+ << "MB for transposition table." << std::endl;
+ exit(EXIT_FAILURE);
}
+
+ clear(); // Operator new is not guaranteed to initialize memory to zero
}
-/// TranspositionTable::clear overwrites the entire transposition table
+/// TranspositionTable::clear() overwrites the entire transposition table
/// 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 * 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. 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. A TTEntry of type VALUE_TYPE_EVAL
-/// never replaces another entry for the same position.
+/// 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 Key posKey, Value v, ValueType t, Depth d, Move m) {
+void TranspositionTable::store(const Key posKey, Value v, Bound 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 inside the cluster
tte = replace = first_entry(posKey);
- for (int i = 0; i < 4; i++, tte++)
+
+ for (int i = 0; i < ClusterSize; i++, tte++)
{
- if (!tte->key() || tte->key() == posKey) // empty or overwrite old
+ 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;
-
+ // Preserve any existing ttMove
if (m == MOVE_NONE)
m = tte->move();
- *tte = TTEntry(posKey, v, t, d, m, generation);
+ tte->save(posKey32, v, t, d, m, generation, statV, kingD);
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);
+ // Implement replace strategy
+ c1 = (replace->generation() == generation ? 2 : 0);
+ c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0);
+ c3 = (tte->depth() < replace->depth() ? 1 : 0);
if (c1 + c2 + c3 > 0)
replace = tte;
}
- *replace = TTEntry(posKey, v, t, d, m, generation);
- writes++;
+ replace->save(posKey32, v, t, d, m, generation, statV, kingD);
}
-/// TranspositionTable::retrieve looks up the current position in the
-/// transposition table. Returns a pointer to the TTEntry or NULL
-/// if position is not found.
+/// TranspositionTable::probe() 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 {
+TTEntry* TranspositionTable::probe(const Key posKey) const {
- TTEntry *tte = first_entry(posKey);
+ uint32_t posKey32 = posKey >> 32;
+ TTEntry* tte = first_entry(posKey);
- for (int i = 0; i < 4; i++, tte++)
- if (tte->key() == posKey)
+ 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.
-
-inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
-
- return entries + (int(posKey & (size - 1)) << 2);
-}
-
/// TranspositionTable::new_search() is called at the beginning of every new
/// 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[]) {
-
- StateInfo st;
- Position p(pos);
-
- for (int i = 0; pv[i] != MOVE_NONE; i++)
- {
- store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
- p.do_move(pv[i], st);
- }
-}
-
-
-/// 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.
-
-void TranspositionTable::extract_pv(const Position& pos, Move pv[]) {
-
- 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(), p.pinned_pieces(p.side_to_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;
-}
-
-
-/// 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() const {
-
- double N = double(size) * 4.0;
- return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N))));
}