// We're ready to start thinking. Call the iterative deepening loop function
Value v = id_loop(pos, searchMoves);
-
if (UseLSNFiltering)
{
// Step 1. If this is sudden death game and our position is hopeless,
// searchMoves are verified, copied, scored and sorted
RootMoveList rml(p, searchMoves);
+ // Handle special case of searching on a mate/stale position
if (rml.move_count() == 0)
{
if (PonderSearch)
int prevDelta1 = IterationInfo[Iteration - 1].speculatedValue - IterationInfo[Iteration - 2].speculatedValue;
int prevDelta2 = IterationInfo[Iteration - 2].speculatedValue - IterationInfo[Iteration - 3].speculatedValue;
- int delta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16);
-
- delta = (delta + 7) / 8 * 8; // Round to match grainSize
- AspirationDelta = delta;
+ AspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16);
+ AspirationDelta = (AspirationDelta + 7) / 8 * 8; // Round to match grainSize
- alpha = Max(IterationInfo[Iteration - 1].value - delta, -VALUE_INFINITE);
- beta = Min(IterationInfo[Iteration - 1].value + delta, VALUE_INFINITE);
+ alpha = Max(IterationInfo[Iteration - 1].value - AspirationDelta, -VALUE_INFINITE);
+ beta = Min(IterationInfo[Iteration - 1].value + AspirationDelta, VALUE_INFINITE);
}
else
{
Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta) {
- Value alpha = oldAlpha;
+ int64_t nodes;
+ Move move;
+ StateInfo st;
+ Depth depth, ext, newDepth;
Value value;
CheckInfo ci(pos);
int researchCount = 0;
+ bool moveIsCheck, captureOrPromotion, dangerous;
+ Value alpha = oldAlpha;
bool isCheck = pos.is_check();
// Evaluate the position statically
EvalInfo ei;
- if (!isCheck)
- ss[0].eval = evaluate(pos, ei, 0);
- else
- ss[0].eval = VALUE_NONE;
+ ss[0].eval = !isCheck ? evaluate(pos, ei, 0) : VALUE_NONE;
- while(1) // Fail low loop
+ while (1) // Fail low loop
{
// Loop through all the moves in the root move list
rml.set_move_score(i, -VALUE_INFINITE);
continue;
}
- int64_t nodes;
- Move move;
- StateInfo st;
- Depth depth, ext, newDepth;
RootMoveNumber = i + 1;
FailHigh = false;
<< " currmovenumber " << RootMoveNumber << endl;
// Decide search depth for this move
- bool moveIsCheck = pos.move_is_check(move);
- bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
- bool dangerous;
- depth = (Iteration - 2) * OnePly + InitialDepth;
+ moveIsCheck = pos.move_is_check(move);
+ captureOrPromotion = pos.move_is_capture_or_promotion(move);
+ depth = (Iteration - 2) * OnePly + InitialDepth;
ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
newDepth = depth + ext;
pos.undo_move(move);
+ // Can we exit fail high loop ?
if (AbortSearch || value < beta)
- break; // We are not failing high
+ break;
// We are failing high and going to do a research. It's important to update score
// before research in case we run out of time while researching.
nodes_searched(), value, type, ss[0].pv) << endl;
}
- // Prepare for research
+ // Prepare for a research after a fail high, each time with a wider window
researchCount++;
beta = Min(beta + AspirationDelta * (1 << researchCount), VALUE_INFINITE);
FailLow = (alpha == oldAlpha);
}
+ // Can we exit fail low loop ?
if (AbortSearch || alpha > oldAlpha)
- break; // End search, we are not failing low
+ break;
- // Prepare for research
+ // Prepare for a research after a fail low, each time with a wider window
researchCount++;
alpha = Max(alpha - AspirationDelta * (1 << researchCount), -VALUE_INFINITE);
oldAlpha = alpha;
&& !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[ply]))
- {
+ {
ss[ply].reduction = reduction(moveCount, LogLimit, BaseReduction, Gradient);
if (ss[ply].reduction)
{
// Update current move
movesSearched[moveCount++] = ss[ply].currentMove = move;
- // Futility pruning for captures
- // FIXME: test disabling 'Futility pruning for captures'
- // FIXME: test with 'newDepth < RazorDepth'
- Color them = opposite_color(pos.side_to_move());
-
- if ( !isCheck
- && newDepth < SelectiveDepth
- && !dangerous
- && pos.move_is_capture(move)
- && !pos.move_is_check(move, ci)
- && !move_is_promotion(move)
- && move != ttMove
- && !move_is_ep(move)
- && (pos.type_of_piece_on(move_to(move)) != PAWN || !pos.pawn_is_passed(them, move_to(move)))) // Do not prune passed pawn captures
- {
- int preFutilityValueMargin = 0;
-
- if (newDepth >= OnePly)
- preFutilityValueMargin = FutilityMargins[int(newDepth)];
-
- Value futilityCaptureValue = ss[ply].eval + pos.endgame_value_of_piece_on(move_to(move)) + preFutilityValueMargin + ei.futilityMargin + 90;
-
- if (futilityCaptureValue < beta)
- {
- if (futilityCaptureValue > bestValue)
- bestValue = futilityCaptureValue;
- continue;
- }
- }
-
// Futility pruning
if ( !isCheck
&& !dangerous
const TTEntry* tte = NULL;
int moveCount = 0;
bool pvNode = (beta - alpha != 1);
+ Value oldAlpha = alpha;
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
if (bestValue >= beta)
{
// Store the score to avoid a future costly evaluation() call
- if (!isCheck && !tte && ei.futilityMargin == 0)
+ if (!isCheck && !tte && ei.futilityMargin[pos.side_to_move()] == 0)
TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EV_LO, Depth(-127*OnePly), MOVE_NONE);
return bestValue;
MovePicker mp = MovePicker(pos, ttMove, deepChecks ? Depth(0) : depth, H);
CheckInfo ci(pos);
enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
- futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin;
+ futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin[pos.side_to_move()];
// Loop through the moves until no moves remain or a beta cutoff
// occurs.
// Update transposition table
Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
- if (bestValue < beta)
+ if (bestValue <= oldAlpha)
{
// If bestValue isn't changed it means it is still the static evaluation
// of the node, so keep this info to avoid a future evaluation() call.
- ValueType type = (bestValue == staticValue && !ei.futilityMargin ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
+ ValueType type = (bestValue == staticValue && !ei.futilityMargin[pos.side_to_move()] ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE);
}
- else
+ else if (bestValue >= beta)
{
move = ss[ply].pv[ply];
TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move);
if (!pos.move_is_capture_or_promotion(move))
update_killers(move, ss[ply]);
}
+ else
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss[ply].pv[ply]);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) : count(0) {
+ SearchStack ss[PLY_MAX_PLUS_2];
MoveStack mlist[MaxRootMoves];
+ StateInfo st;
bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
// Generate all legal moves
continue;
// Find a quick score for the move
- StateInfo st;
- SearchStack ss[PLY_MAX_PLUS_2];
init_ss_array(ss);
-
+ pos.do_move(cur->move, st);
moves[count].move = cur->move;
- pos.do_move(moves[count].move, st);
moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
- pos.undo_move(moves[count].move);
- moves[count].pv[0] = moves[count].move;
+ moves[count].pv[0] = cur->move;
moves[count].pv[1] = MOVE_NONE;
+ pos.undo_move(cur->move);
count++;
}
sort();
// reduction() returns reduction in plies based on moveCount and depth.
// Reduction is always at least one ply.
- Depth reduction(int moveCount, float logLimit, float baseReduction, float gradient) {
+ Depth reduction(int moveCount, float logLimit, float baseReduction, float gradient) {
if (ln(moveCount) < logLimit)
return Depth(0);
projects / stockfish / blobdiff