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Sync search() and qsearch() alpha update

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Change qsearch() to reflect alpha update logic
of search().

To be consistent changed also moves loop condition and
futility pruning condition.

No regression after 5072 games at TC 10"+0.1

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2011-08-07 10:29:47 +01:00
parent 4a71c86270
commit 06e0d48794
1 changed files with 22 additions and 16 deletions
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38
src/search.cpp
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@@ -712,7 +712,7 @@ namespace {
Depth ext, newDepth;
ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
Value refinedValue, nullValue, futilityBase, futilityValue;
bool isPvMove, inCheck, singularExtensionNode, givesCheck, captureOrPromotion, dangerous;
int moveCount = 0, playedMoveCount = 0;
Thread& thread = Threads[pos.thread()];
@@ -1070,19 +1070,19 @@ split_point_start: // At split points actual search starts from here
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker.
Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
futilityValueScaled = futilityBase + futility_margin(predictedDepth, moveCount)
+ H.gain(pos.piece_on(move_from(move)), move_to(move));
futilityValue = futilityBase + futility_margin(predictedDepth, moveCount)
+ H.gain(pos.piece_on(move_from(move)), move_to(move));
if (futilityValueScaled < beta)
if (futilityValue < beta)
{
if (SpNode)
{
lock_grab(&(sp->lock));
if (futilityValueScaled > sp->bestValue)
sp->bestValue = bestValue = futilityValueScaled;
if (futilityValue > sp->bestValue)
sp->bestValue = bestValue = futilityValue;
}
else if (futilityValueScaled > bestValue)
bestValue = futilityValueScaled;
else if (futilityValue > bestValue)
bestValue = futilityValue;
continue;
}
@@ -1298,6 +1298,7 @@ split_point_start: // At split points actual search starts from here
bool inCheck, enoughMaterial, givesCheck, evasionPrunable;
const TTEntry* tte;
Depth ttDepth;
ValueType vt;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
@@ -1368,7 +1369,7 @@ split_point_start: // At split points actual search starts from here
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
while ( alpha < beta
while ( bestValue < beta
&& (move = mp.get_next_move()) != MOVE_NONE)
{
assert(move_is_ok(move));
@@ -1388,10 +1389,11 @@ split_point_start: // At split points actual search starts from here
+ piece_value_endgame(pos.piece_on(move_to(move)))
+ (move_is_ep(move) ? PawnValueEndgame : VALUE_ZERO);
if (futilityValue < alpha)
if (futilityValue < beta)
{
if (futilityValue > bestValue)
bestValue = futilityValue;
continue;
}
@@ -1450,11 +1452,12 @@ split_point_start: // At split points actual search starts from here
if (value > bestValue)
{
bestValue = value;
if (value > alpha)
{
ss->bestMove = move;
if ( PvNode
&& value > alpha
&& value < beta) // We want always alpha < beta
alpha = value;
ss->bestMove = move;
}
}
}
@@ -1464,8 +1467,11 @@ split_point_start: // At split points actual search starts from here
return value_mated_in(ss->ply);
// Update transposition table
ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin);
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
: bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);