Skip to content

Commit

Permalink
Reformat stats update
Browse files Browse the repository at this point in the history 
Rewritten in a way to have explicit in the search
the bonus/penalty we apply: hopefully this will lead
to further simplification/fix of current rather messy
stats update code.

No functional change.
  • Loading branch information
@mcostalba
mcostalba committed Aug 25, 2016
1 parent 0b4f6e5 commit 3e739f8
Showing 1 changed file with 62 additions and 41 deletions.
103 changes: 62 additions & 41 deletions src/search.cpp
View file
Expand Up @@ -168,7 +168,8 @@ namespace {
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
void update_pv(Move* pv, Move move, Move* childPv);
void update_stats(const Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt);
void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, Value bonus);
void update_opponent_stats(const Position& pos, Stack* ss, Value bonus);
void check_time();

} // namespace
Expand Down Expand Up @@ -637,8 +638,22 @@ namespace {

// If ttMove is quiet, update killers, history, counter move on TT hit
if (ttValue >= beta && ttMove)
update_stats(pos, ss, ttMove, depth, nullptr, 0);
{
int d = depth / ONE_PLY;

if (!pos.capture_or_promotion(ttMove))
{
Value bonus = Value(d * d + 2 * d - 2);
update_stats(pos, ss, ttMove, nullptr, 0, bonus);
}

// Extra penalty for a quiet TT move in previous ply when it gets refuted
if ((ss-1)->moveCount == 1 && !pos.captured_piece_type())
{
Value penalty = Value(d * d + 4 * d + 1);
update_opponent_stats(pos, ss, -penalty);
}
}
return ttValue;
}

Expand Down Expand Up @@ -1111,26 +1126,32 @@ namespace {
if (!moveCount)
bestValue = excludedMove ? alpha
: inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()];

// Quiet best move: update killers, history and countermoves
else if (bestMove)
update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount);
{
int d = depth / ONE_PLY;

// Quiet best move: update killers, history and countermoves
if (!pos.capture_or_promotion(bestMove))
{
Value bonus = Value(d * d + 2 * d - 2);
update_stats(pos, ss, bestMove, quietsSearched, quietCount, bonus);
}

// Extra penalty for a quiet TT move in previous ply when it gets refuted
if ((ss-1)->moveCount == 1 && !pos.captured_piece_type())
{
Value penalty = Value(d * d + 4 * d + 1);
update_opponent_stats(pos, ss, -penalty);
}
}
// Bonus for prior countermove that caused the fail low
else if ( depth >= 3 * ONE_PLY
&& !pos.captured_piece_type()
&& is_ok((ss-1)->currentMove))
{
Square prevSq = to_sq((ss-1)->currentMove);
Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + 2 * depth / ONE_PLY - 2);
if ((ss-2)->counterMoves)
(ss-2)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus);

if ((ss-3)->counterMoves)
(ss-3)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus);

if ((ss-5)->counterMoves)
(ss-5)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus);
int d = depth / ONE_PLY;
Value bonus = Value(d * d + 2 * d - 2);
update_opponent_stats(pos, ss, bonus);
}

tte->save(posKey, value_to_tt(bestValue, ss->ply),
Expand Down Expand Up @@ -1390,34 +1411,33 @@ namespace {
}


// update_stats() updates killers, history, countermove and countermove plus
// follow-up move history when a new quiet best move is found.
// update_opponent_stats() updates countermoves for prior opponent move, i.e.
// (ss-1)->currentMove. Called for both capture and non-capture moves.

void update_stats(const Position& pos, Stack* ss, Move move,
Depth depth, Move* quiets, int quietsCnt) {
void update_opponent_stats(const Position& pos, Stack* ss, Value bonus) {

Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + 2 * depth / ONE_PLY - 2);
Square prevSq = to_sq((ss-1)->currentMove);

// Extra penalty for a quiet TT move in previous ply when it gets refuted
if ((ss-1)->moveCount == 1 && !pos.captured_piece_type())
{
CounterMoveStats* fmh = (ss-2)->counterMoves;
CounterMoveStats* cmh2 = (ss-3)->counterMoves;
CounterMoveStats* cmh3 = (ss-5)->counterMoves;
CounterMoveStats* cmh = (ss-2)->counterMoves;
CounterMoveStats* fmh1 = (ss-3)->counterMoves;
CounterMoveStats* fmh2 = (ss-5)->counterMoves;

if (fmh)
fmh->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1);
if (cmh)
cmh->update(pos.piece_on(prevSq), prevSq, bonus);

if (cmh2)
cmh2->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1);
if (fmh1)
fmh1->update(pos.piece_on(prevSq), prevSq, bonus);

if (cmh3)
cmh3->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1);
}
if (fmh2)
fmh2->update(pos.piece_on(prevSq), prevSq, bonus);
}

if (pos.capture_or_promotion(move))
return;

// update_stats() updates killers, history, countermove and countermove plus
// follow-up move history when a new quiet best move is found.

void update_stats(const Position& pos, Stack* ss, Move move,
Move* quiets, int quietsCnt, Value bonus) {

if (ss->killers[0] != move)
{
Expand All @@ -1426,22 +1446,23 @@ namespace {
}

CounterMoveStats* cmh = (ss-1)->counterMoves;
CounterMoveStats* fmh = (ss-2)->counterMoves;
CounterMoveStats* fmh1 = (ss-2)->counterMoves;
CounterMoveStats* fmh2 = (ss-4)->counterMoves;

Color c = pos.side_to_move();
Thread* thisThread = pos.this_thread();

thisThread->history.update(pos.moved_piece(move), to_sq(move), bonus);
thisThread->fromTo.update(c, move, bonus);

if (cmh)
{
Square prevSq = to_sq((ss-1)->currentMove);
thisThread->counterMoves.update(pos.piece_on(prevSq), prevSq, move);
cmh->update(pos.moved_piece(move), to_sq(move), bonus);
}

if (fmh)
fmh->update(pos.moved_piece(move), to_sq(move), bonus);
if (fmh1)
fmh1->update(pos.moved_piece(move), to_sq(move), bonus);

if (fmh2)
fmh2->update(pos.moved_piece(move), to_sq(move), bonus);
Expand All @@ -1455,8 +1476,8 @@ namespace {
if (cmh)
cmh->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);

if (fmh)
fmh->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
if (fmh1)
fmh1->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);

if (fmh2)
fmh2->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
Expand Down

1 comment on commit 3e739f8

@Stefano80
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Great, now I can understand what is going on there!

Please sign in to comment.