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Remove history counters

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Instead decrement history value on failure.

After 999 games at 1+0

Mod vs Orig  +236 =558 -204 51.60% +11 ELO

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2009-12-09 14:40:38 +01:00
parent 7bc72d092f
commit 2161d8b0b3
3 changed files with 13 additions and 33 deletions
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src/search.cpp
+8 -12
View File
@@ -288,7 +288,7 @@ namespace {
bool move_is_killer(Move m, const SearchStack& ss);
Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
bool ok_to_do_nullmove(const Position& pos);
bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d);
bool ok_to_prune(const Position& pos, Move m, Move threat);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
void update_killers(Move m, SearchStack& ss);
@@ -1510,9 +1510,9 @@ namespace {
&& !captureOrPromotion
&& move != ttMove)
{
// History pruning. See ok_to_prune() definition
// Move count based pruning
if ( moveCount >= FutilityMoveCountMargin
&& ok_to_prune(pos, move, ss[ply].threatMove, depth)
&& ok_to_prune(pos, move, ss[ply].threatMove)
&& bestValue > value_mated_in(PLY_MAX))
continue;
@@ -1841,9 +1841,9 @@ namespace {
&& !dangerous
&& !captureOrPromotion)
{
// History pruning. See ok_to_prune() definition
// Move count based pruning
if ( moveCount >= 2 + int(sp->depth)
&& ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth)
&& ok_to_prune(pos, move, ss[sp->ply].threatMove)
&& sp->bestValue > value_mated_in(PLY_MAX))
continue;
@@ -2464,7 +2464,7 @@ namespace {
// non-tactical moves late in the move list close to the leaves are
// candidates for pruning.
bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d) {
bool ok_to_prune(const Position& pos, Move m, Move threat) {
assert(move_is_ok(m));
assert(threat == MOVE_NONE || move_is_ok(threat));
@@ -2498,11 +2498,7 @@ namespace {
&& pos.move_attacks_square(m, tto))
return false;
// Case 4: Don't prune moves with good history
if (!H.ok_to_prune(pos.piece_on(mfrom), mto, d))
return false;
// Case 5: If the moving piece in the threatened move is a slider, don't
// Case 4: If the moving piece in the threatened move is a slider, don't
// prune safe moves which block its ray.
if ( !PruneBlockingMoves
&& threat != MOVE_NONE
@@ -2543,7 +2539,7 @@ namespace {
{
assert(m != movesSearched[i]);
if (!pos.move_is_capture_or_promotion(movesSearched[i]))
H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]));
H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]), depth);
}
}