X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=bc26606721413eb90ecae8923c7d4238960892d2;hp=57dd00790e816670cea1bdfbfea870896492dce5;hb=605b3aedd5b2cc530db417fc8bb57cc45200cca1;hpb=6c0a37bbf2ecb828cb41cb3cfac122f34c2a6e4b

diff --git a/src/tt.cpp b/src/tt.cpp
index 57dd0079..bc266067 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -23,7 +23,6 @@
 ////
 
 #include <cassert>
-#include <cmath>
 #include <cstring>
 
 #include "movegen.h"
@@ -38,7 +37,7 @@ TranspositionTable TT;
 
 TranspositionTable::TranspositionTable() {
 
-  size = overwrites = 0;
+  size = 0;
   entries = 0;
   generation = 0;
 }
@@ -72,7 +71,6 @@ void TranspositionTable::set_size(size_t mbSize) {
                     << " MB for transposition table." << std::endl;
           Application::exit_with_failure();
       }
-      clear();
   }
 }
 
@@ -128,7 +126,6 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d,
           replace = tte;
   }
   replace->save(posKey32, v, t, d, m, generation, statV, kingD);
-  overwrites++;
 }
 
 
@@ -155,9 +152,7 @@ TTEntry* TranspositionTable::retrieve(const Key posKey) const {
 /// entries from the current search.
 
 void TranspositionTable::new_search() {
-
   generation++;
-  overwrites = 0;
 }
 
 
@@ -181,11 +176,11 @@ void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
 }
 
 
-/// 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.
+/// TranspositionTable::extract_pv() builds a PV by adding moves from the
+/// transposition table. We consider also failing high nodes and not only
+/// VALUE_TYPE_EXACT nodes. This allow to always have a ponder move even
+/// when we fail high at root and also a long PV to print that is important
+/// for position analysis.
 
 void TranspositionTable::extract_pv(const Position& pos, Move bestMove, Move pv[], const int PLY_MAX) {
 
@@ -199,11 +194,8 @@ void TranspositionTable::extract_pv(const Position& pos, Move bestMove, Move pv[
   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)
@@ -213,14 +205,3 @@ void TranspositionTable::extract_pv(const Position& pos, Move bestMove, Move pv[
   }
   pv[ply] = MOVE_NONE;
 }
-
-
-/// TranspositionTable::full() returns the permill of all transposition table
-/// 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) * ClusterSize;
-  return int(1000 * (1 - exp(overwrites * log(1.0 - 1.0/N))));
-}