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Code Issues Releases Wiki Activity

Space inflate qsearch

Browse source 
No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2008-09-07 08:31:30 +02:00
parent d517080ab6
commit 6c592955e1
1 changed files with 91 additions and 80 deletions
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101
src/search.cpp
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@ -242,7 +242,6 @@ namespace {
bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
bool fail_high_ply_1();
int current_search_time();
int nps();
@ -1060,6 +1059,7 @@ namespace {
// Mate distance pruning
if (value_mated_in(ply) >= beta)
return beta;
if (value_mate_in(ply + 1) < beta)
return beta - 1;
@ -1182,7 +1182,8 @@ namespace {
if (depth < 3 * OnePly && approximateEval < beta)
{
if (futilityValue == VALUE_NONE)
futilityValue = evaluate(pos, ei, threadID) + (depth < 2 * OnePly ? FutilityMargin1 : FutilityMargin2);
futilityValue = evaluate(pos, ei, threadID)
+ (depth < 2 * OnePly ? FutilityMargin1 : FutilityMargin2);
if (futilityValue < beta)
{
@ -1230,6 +1231,7 @@ namespace {
bestValue = value;
if (value >= beta)
update_pv(ss, ply);
if (value == value_mate_in(ply + 1))
ss[ply].mateKiller = move;
}
@ -1291,8 +1293,6 @@ namespace {
Value qsearch(Position &pos, SearchStack ss[], Value alpha, Value beta,
Depth depth, int ply, int threadID) {
Value staticValue, bestValue, value;
EvalInfo ei;
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
@ -1300,6 +1300,8 @@ namespace {
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
EvalInfo ei;
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
if (AbortSearch || thread_should_stop(threadID))
@ -1311,21 +1313,20 @@ namespace {
return VALUE_DRAW;
// Evaluate the position statically:
staticValue = evaluate(pos, ei, threadID);
Value staticValue = evaluate(pos, ei, threadID);
if(ply == PLY_MAX - 1) return staticValue;
if (ply == PLY_MAX - 1)
return staticValue;
// Initialize "stand pat score", and return it immediately if it is
// at least beta.
if(pos.is_check())
bestValue = -VALUE_INFINITE;
else {
bestValue = staticValue;
Value bestValue = (pos.is_check() ? -VALUE_INFINITE : staticValue);
if (bestValue >= beta)
return bestValue;
if (bestValue > alpha)
alpha = bestValue;
}
// Initialize a MovePicker object for the current position, and prepare
// to search the moves. Because the depth is <= 0 here, only captures,
@ -1339,28 +1340,34 @@ namespace {
// Loop through the moves until no moves remain or a beta cutoff
// occurs.
while(alpha < beta && ((move = mp.get_next_move()) != MOVE_NONE)) {
UndoInfo u;
while ( alpha < beta
&& (move = mp.get_next_move()) != MOVE_NONE)
{
assert(move_is_ok(move));
bool moveIsCheck = pos.move_is_check(move, dcCandidates);
bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
assert(move_is_ok(move));
moveCount++;
ss[ply].currentMove = move;
// Futility pruning
if(UseQSearchFutilityPruning && !isCheck && !moveIsCheck &&
!move_promotion(move) && !moveIsPassedPawnPush &&
beta - alpha == 1 &&
pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame) {
Value futilityValue =
staticValue
if ( UseQSearchFutilityPruning
&& !isCheck
&& !moveIsCheck
&& !move_promotion(move)
&& !moveIsPassedPawnPush
&& beta - alpha == 1
&& pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame)
{
Value futilityValue = staticValue
+ Max(pos.midgame_value_of_piece_on(move_to(move)),
pos.endgame_value_of_piece_on(move_to(move)))
+ FutilityMargin0
+ ei.futilityMargin;
if(futilityValue < alpha) {
if (futilityValue < alpha)
{
if (futilityValue > bestValue)
bestValue = futilityValue;
continue;
@ -1368,23 +1375,27 @@ namespace {
}
// Don't search captures and checks with negative SEE values.
if(!isCheck && !move_promotion(move) &&
pos.midgame_value_of_piece_on(move_from(move)) >
pos.midgame_value_of_piece_on(move_to(move)) &&
pos.see(move) < 0)
if ( !isCheck
&& !move_promotion(move)
&& (pos.midgame_value_of_piece_on(move_from(move)) >
pos.midgame_value_of_piece_on(move_to(move)))
&& pos.see(move) < 0)
continue;
// Make and search the move.
UndoInfo u;
pos.do_move(move, u, dcCandidates);
value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
pos.undo_move(move, u);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
// New best move?
if(value > bestValue) {
if (value > bestValue)
{
bestValue = value;
if(value > alpha) {
if (value > alpha)
{
alpha = value;
update_pv(ss, ply);
}
@ -1626,22 +1637,6 @@ namespace {
}
// ok_to_use_TT() returns true if a transposition table score
// can be used at a given point in search.
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply) {
Value v = value_from_tt(tte->value(), ply);
return ( tte->depth() >= depth
|| v >= Max(value_mate_in(100), beta)
|| v < Min(value_mated_in(100), beta))
&& ( (is_lower_bound(tte->type()) && v >= beta)
|| (is_upper_bound(tte->type()) && v < beta));
}
/// The RootMove class
// Constructor
@ -2033,6 +2028,22 @@ namespace {
}
// ok_to_use_TT() returns true if a transposition table score
// can be used at a given point in search.
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply) {
Value v = value_from_tt(tte->value(), ply);
return ( tte->depth() >= depth
|| v >= Max(value_mate_in(100), beta)
|| v < Min(value_mated_in(100), beta))
&& ( (is_lower_bound(tte->type()) && v >= beta)
|| (is_upper_bound(tte->type()) && v < beta));
}
// fail_high_ply_1() checks if some thread is currently resolving a fail
// high at ply 1 at the node below the first root node. This information
// is used for time managment.