X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=57dd00790e816670cea1bdfbfea870896492dce5;hp=a0cc7922395cb2a86bba11a1adbd29eacd78f305;hb=6c0a37bbf2ecb828cb41cb3cfac122f34c2a6e4b;hpb=a88e762b4ea4a3696ecc0431237f54090a5aa1e2

diff --git a/src/tt.cpp b/src/tt.cpp
index a0cc7922..57dd0079 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) 2008-2010 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
@@ -26,8 +26,11 @@
 #include <cmath>
 #include <cstring>
 
+#include "movegen.h"
 #include "tt.h"
 
+// The main transposition table
+TranspositionTable TT;
 
 ////
 //// Functions
@@ -35,7 +38,7 @@
 
 TranspositionTable::TranspositionTable() {
 
-  size = writes = 0;
+  size = overwrites = 0;
   entries = 0;
   generation = 0;
 }
@@ -49,22 +52,20 @@ 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 <= 4096);
+  size_t newSize = 1024;
 
-  unsigned newSize = 1024;
-
-  // 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))
+  // We store a cluster of ClusterSize number of TTEntry for each position
+  // and newSize is the maximum number of storable positions.
+  while ((2 * newSize) * sizeof(TTCluster) <= (mbSize << 20))
       newSize *= 2;
 
   if (newSize != size)
   {
       size = newSize;
       delete [] entries;
-      entries = new TTEntry[size * 4];
+      entries = new TTCluster[size];
       if (!entries)
       {
           std::cerr << "Failed to allocate " << mbSize
@@ -83,7 +84,7 @@ void TranspositionTable::set_size(unsigned mbSize) {
 
 void TranspositionTable::clear() {
 
-  memset(entries, 0, size * 4 * sizeof(TTEntry));
+  memset(entries, 0, size * sizeof(TTCluster));
 }
 
 
@@ -97,37 +98,37 @@ void TranspositionTable::clear() {
 /// 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 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(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 exsisting 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
+
+      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);
+      c1 = (replace->generation() == generation ?  2 : 0);
+      c2 = (tte->generation() == generation ? -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);
+  overwrites++;
 }
 
 
@@ -137,24 +138,17 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d,
 
 TTEntry* TranspositionTable::retrieve(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
@@ -163,7 +157,7 @@ inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
 void TranspositionTable::new_search() {
 
   generation++;
-  writes = 0;
+  overwrites = 0;
 }
 
 
@@ -175,22 +169,58 @@ void TranspositionTable::new_search() {
 void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
 
   StateInfo st;
-  Position p(pos);
+  Position p(pos, pos.thread());
 
   for (int i = 0; pv[i] != MOVE_NONE; i++)
   {
-      store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
+      TTEntry *tte = retrieve(p.get_key());
+      if (!tte || tte->move() != pv[i])
+          store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i], VALUE_NONE, VALUE_NONE);
       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 bestMove, Move pv[], const int PLY_MAX) {
+
+  const TTEntry* tte;
+  StateInfo st;
+  Position p(pos, pos.thread());
+  int ply = 0;
+
+  assert(bestMove != MOVE_NONE);
+
+  pv[ply] = bestMove;
+  p.do_move(pv[ply++], st);
+
+  // Extract moves from TT when possible. We try hard to always
+  // get a ponder move, that's the reason of ply < 2 conditions.
+  while (   (tte = retrieve(p.get_key())) != NULL
+         && tte->move() != MOVE_NONE
+         && (tte->type() == VALUE_TYPE_EXACT || ply < 2)
+         && move_is_legal(p, tte->move())
+         && (!p.is_draw() || ply < 2)
+         && ply < PLY_MAX)
+  {
+      pv[ply] = tte->move();
+      p.do_move(pv[ply++], st);
+  }
+  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.
+/// entries which have received at least one overwrite 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))));
+  double N = double(size) * ClusterSize;
+  return int(1000 * (1 - exp(overwrites * log(1.0 - 1.0/N))));
 }