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Synchronize search_pv() with search take I

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Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Joona Kiiski 2010-02-24 13:41:22 +02:00 • committed by Marco Costalba
parent 9eedc0a463
commit 0980f43ab0
1 changed files with 26 additions and 23 deletions
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49
src/search.cpp
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@ -1052,37 +1052,50 @@ namespace {
if (depth < OnePly) if (depth < OnePly)
return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID); return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID);
// Initialize, and make an early exit in case of an aborted search, // Step 1. Initialize node and poll
// an instant draw, maximum ply reached, etc. // Polling can abort search.
init_node(ss, ply, threadID); init_node(ss, ply, threadID);
// After init_node() that calls poll() // Step 2. Check for aborted search and immediate draw
if (AbortSearch || TM.thread_should_stop(threadID)) if (AbortSearch || TM.thread_should_stop(threadID))
return Value(0); return Value(0);
if (pos.is_draw() || ply >= PLY_MAX - 1) if (pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW; return VALUE_DRAW;
// Mate distance pruning // Step 3. Mate distance pruning
oldAlpha = alpha; oldAlpha = alpha;
alpha = Max(value_mated_in(ply), alpha); alpha = Max(value_mated_in(ply), alpha);
beta = Min(value_mate_in(ply+1), beta); beta = Min(value_mate_in(ply+1), beta);
if (alpha >= beta) if (alpha >= beta)
return alpha; return alpha;
// Transposition table lookup. At PV nodes, we don't use the TT for // Step 4. Transposition table lookup
// pruning, but only for move ordering. This is to avoid problems in // At PV nodes, we don't use the TT for pruning, but only for move ordering.
// the following areas: // This is to avoid problems in the following areas:
// //
// * Repetition draw detection // * Repetition draw detection
// * Fifty move rule detection // * Fifty move rule detection
// * Searching for a mate // * Searching for a mate
// * Printing of full PV line // * Printing of full PV line
//
tte = TT.retrieve(pos.get_key()); tte = TT.retrieve(pos.get_key());
ttMove = (tte ? tte->move() : MOVE_NONE); ttMove = (tte ? tte->move() : MOVE_NONE);
// Go with internal iterative deepening if we don't have a TT move // Step 5. Evaluate the position statically
// At PV nodes we do this only to update gain statistics
isCheck = pos.is_check();
if (!isCheck)
{
EvalInfo ei;
ss[ply].eval = evaluate(pos, ei, threadID);
update_gains(pos, ss[ply - 1].currentMove, ss[ply - 1].eval, ss[ply].eval);
}
// Step 6. Razoring (is omitted in PV nodes)
// Step 7. Static null move pruning (is omitted in PV nodes)
// Step 8. Null move search with verification search (is omitted in PV nodes)
// Step 9. Internal iterative deepening
if ( UseIIDAtPVNodes if ( UseIIDAtPVNodes
&& depth >= 5*OnePly && depth >= 5*OnePly
&& ttMove == MOVE_NONE) && ttMove == MOVE_NONE)
@ -1092,24 +1105,14 @@ namespace {
tte = TT.retrieve(pos.get_key()); tte = TT.retrieve(pos.get_key());
} }
isCheck = pos.is_check(); // Step 10. Loop through moves
if (!isCheck) // Loop through all legal moves until no moves remain or a beta cutoff occurs
{
// Update gain statistics of the previous move that lead
// us in this position.
EvalInfo ei;
ss[ply].eval = evaluate(pos, ei, threadID);
update_gains(pos, ss[ply - 1].currentMove, ss[ply - 1].eval, ss[ply].eval);
}
// Initialize a MovePicker object for the current position, and prepare // Initialize a MovePicker object for the current position
// to search all moves
mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move())); mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
CheckInfo ci(pos);
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]); MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
CheckInfo ci(pos);
// Loop through all legal moves until no moves remain or a beta cutoff
// occurs.
while ( alpha < beta while ( alpha < beta
&& (move = mp.get_next_move()) != MOVE_NONE && (move = mp.get_next_move()) != MOVE_NONE
&& !TM.thread_should_stop(threadID)) && !TM.thread_should_stop(threadID))