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Synchronize search_pv() with search take II

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No functional change

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Joona Kiiski 2010-02-24 14:05:31 +02:00 • committed by Marco Costalba
parent 0980f43ab0
commit 3c31776a20
1 changed files with 20 additions and 9 deletions
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29
src/search.cpp
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@ -1123,7 +1123,7 @@ namespace {
moveIsCheck = pos.move_is_check(move, ci); moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move); captureOrPromotion = pos.move_is_capture_or_promotion(move);
// Decide the new search depth // Step 11. Decide the new search depth
ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous); ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous);
// Singular extension search. We extend the TT move if its value is much better than // Singular extension search. We extend the TT move if its value is much better than
@ -1149,17 +1149,21 @@ namespace {
newDepth = depth - OnePly + ext; newDepth = depth - OnePly + ext;
// Update current move // Update current move (this must be done after singular extension search)
movesSearched[moveCount++] = ss[ply].currentMove = move; movesSearched[moveCount++] = ss[ply].currentMove = move;
// Make and search the move // Step 12. Futility pruning (is omitted in PV nodes)
// Step 13. Make the move
pos.do_move(move, st, ci, moveIsCheck); pos.do_move(move, st, ci, moveIsCheck);
if (moveCount == 1) // The first move in list is the PV // Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
if (moveCount == 1)
value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID); value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
else else
{ {
// Try to reduce non-pv search depth by one ply if move seems not problematic, // Step 14. Reduced search
// if the move fails high will be re-searched at full depth. // if the move fails high will be re-searched at full depth.
bool doFullDepthSearch = true; bool doFullDepthSearch = true;
@ -1177,19 +1181,24 @@ namespace {
} }
} }
if (doFullDepthSearch) // Go with full depth non-pv search // Step 15. Full depth search
if (doFullDepthSearch)
{ {
ss[ply].reduction = Depth(0); ss[ply].reduction = Depth(0);
value = -search(pos, ss, -alpha, newDepth, ply+1, true, threadID); value = -search(pos, ss, -alpha, newDepth, ply+1, true, threadID);
// Step extra. pv search (only in PV nodes)
if (value > alpha && value < beta) if (value > alpha && value < beta)
value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID); value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
} }
} }
// Step 16. Undo move
pos.undo_move(move); pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
// New best move? // Step 17. Check for new best move
if (value > bestValue) if (value > bestValue)
{ {
bestValue = value; bestValue = value;
@ -1202,7 +1211,7 @@ namespace {
} }
} }
// Split? // Step 18. Check for split
if ( TM.active_threads() > 1 if ( TM.active_threads() > 1
&& bestValue < beta && bestValue < beta
&& depth >= MinimumSplitDepth && depth >= MinimumSplitDepth
@ -1215,11 +1224,13 @@ namespace {
break; break;
} }
// All legal moves have been searched. A special case: If there were // Step 19. Check for mate and stalemate
// All legal moves have been searched and if there were
// no legal moves, it must be mate or stalemate. // no legal moves, it must be mate or stalemate.
if (moveCount == 0) if (moveCount == 0)
return (isCheck ? value_mated_in(ply) : VALUE_DRAW); return (isCheck ? value_mated_in(ply) : VALUE_DRAW);
// Step 20. Update tables
// If the search is not aborted, update the transposition table, // If the search is not aborted, update the transposition table,
// history counters, and killer moves. // history counters, and killer moves.
if (AbortSearch || TM.thread_should_stop(threadID)) if (AbortSearch || TM.thread_should_stop(threadID))