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Further rearrange search()

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No functional change.
This commit is contained in:
Marco Costalba
2012-10-01 09:33:13 +02:00
parent faaa1f1116
commit 1b6b711c44
3 changed files with 46 additions and 47 deletions
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81
src/search.cpp
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@@ -528,46 +528,43 @@ namespace {
Key posKey;
Move ttMove, move, excludedMove, bestMove, threatMove;
Depth ext, newDepth;
Bound bt;
Value bestValue, value, oldAlpha, ttValue;
Value refinedValue, nullValue, futilityValue;
bool pvMove, inCheck, singularExtensionNode, givesCheck;
bool captureOrPromotion, dangerous, doFullDepthSearch;
int moveCount, playedMoveCount;
// Step 1. Initialize node
Thread* thisThread = pos.this_thread();
moveCount = playedMoveCount = 0;
oldAlpha = alpha;
inCheck = pos.in_check();
if (SpNode)
{
sp = ss->sp;
bestMove = sp->bestMove;
threatMove = sp->threatMove;
bestValue = sp->bestValue;
tte = NULL;
ttMove = excludedMove = MOVE_NONE;
ttValue = VALUE_NONE;
assert(sp->bestValue > -VALUE_INFINITE && sp->moveCount > 0);
goto split_point_start;
}
bestValue = -VALUE_INFINITE;
ss->currentMove = threatMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
(ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
// Used to send selDepth info to GUI
if (PvNode && thisThread->maxPly < ss->ply)
thisThread->maxPly = ss->ply;
// Step 1. Initialize node
if (SpNode)
{
tte = NULL;
ttMove = excludedMove = MOVE_NONE;
ttValue = VALUE_NONE;
sp = ss->sp;
bestMove = sp->bestMove;
threatMove = sp->threatMove;
bestValue = sp->bestValue;
assert(bestValue > -VALUE_INFINITE && sp->moveCount > 0);
goto split_point_start;
}
else
{
bestValue = -VALUE_INFINITE;
ss->currentMove = threatMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
(ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
}
if (!RootNode)
{
// Step 2. Check for aborted search and immediate draw
@@ -1005,7 +1002,6 @@ split_point_start: // At split points actual search starts from here
// is not a problem when sorting becuase sort is stable and move
// position in the list is preserved, just the PV is pushed up.
rm.score = -VALUE_INFINITE;
}
if (value > bestValue)
@@ -1016,15 +1012,17 @@ split_point_start: // At split points actual search starts from here
if ( PvNode
&& value > alpha
&& value < beta) // We want always alpha < beta
alpha = value;
{
alpha = bestValue; // Update alpha here!
}
if (SpNode && !thisThread->cutoff_occurred())
{
sp->bestValue = value;
sp->bestMove = move;
sp->bestValue = bestValue;
sp->bestMove = bestMove;
sp->alpha = alpha;
if (value >= beta)
if (bestValue >= beta)
sp->cutoff = true;
}
}
@@ -1037,7 +1035,7 @@ split_point_start: // At split points actual search starts from here
&& !Signals.stop
&& !thisThread->cutoff_occurred())
bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, &bestMove,
depth, threatMove, moveCount, &mp, NT);
depth, threatMove, moveCount, mp, NT);
}
// Step 20. Check for mate and stalemate
@@ -1046,41 +1044,42 @@ split_point_start: // At split points actual search starts from here
// case of Signals.stop or thread.cutoff_occurred() are set, but this is
// harmless because return value is discarded anyhow in the parent nodes.
// If we are in a singular extension search then return a fail low score.
if (!moveCount)
return excludedMove ? oldAlpha : inCheck ? mated_in(ss->ply) : VALUE_DRAW;
// A split node has at least one move, the one tried before to be splitted.
if (!SpNode && !moveCount)
return excludedMove ? alpha : inCheck ? mated_in(ss->ply) : VALUE_DRAW;
// If we have pruned all the moves without searching return a fail-low score
if (bestValue == -VALUE_INFINITE)
{
assert(!playedMoveCount);
bestValue = oldAlpha;
bestValue = alpha;
}
// Step 21. Update tables
// Update transposition table entry, killers and history
if (!SpNode && !Signals.stop && !thisThread->cutoff_occurred())
{
move = bestValue <= oldAlpha ? MOVE_NONE : bestMove;
bt = bestValue <= oldAlpha ? BOUND_UPPER
: bestValue >= beta ? BOUND_LOWER : BOUND_EXACT;
Move ttm = bestValue <= oldAlpha ? MOVE_NONE : bestMove;
Bound bt = bestValue <= oldAlpha ? BOUND_UPPER
: bestValue >= beta ? BOUND_LOWER : BOUND_EXACT;
TT.store(posKey, value_to_tt(bestValue, ss->ply), bt, depth, move, ss->eval, ss->evalMargin);
TT.store(posKey, value_to_tt(bestValue, ss->ply), bt, depth, ttm, ss->eval, ss->evalMargin);
// Update killers and history for non capture cut-off moves
if ( bestValue >= beta
&& !pos.is_capture_or_promotion(move)
&& !pos.is_capture_or_promotion(bestMove)
&& !inCheck)
{
if (move != ss->killers[0])
if (bestMove != ss->killers[0])
{
ss->killers[1] = ss->killers[0];
ss->killers[0] = move;
ss->killers[0] = bestMove;
}
// Increase history value of the cut-off move
Value bonus = Value(int(depth) * int(depth));
H.add(pos.piece_moved(move), to_sq(move), bonus);
H.add(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
// Decrease history of all the other played non-capture moves
for (int i = 0; i < playedMoveCount - 1; i++)