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Code Issues Releases Wiki Activity

Use nullMove only through MovePicker.

Browse source 
No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Joona Kiiski 2009-08-24 18:08:31 +03:00 • committed by Marco Costalba
parent f6d2452916
commit a5d699d62f
2 changed files with 46 additions and 42 deletions
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5
src/movepick.cpp
View file

@ -44,6 +44,7 @@ namespace {
CACHE_LINE_ALIGNMENT
const MovegenPhaseT MainSearchPhaseTable[] = { PH_STOP, PH_NULL_MOVE, PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
const MovegenPhaseT MainSearchNoNullPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
const MovegenPhaseT EvasionsPhaseTable[] = { PH_STOP, PH_EVASIONS, PH_STOP};
const MovegenPhaseT QsearchWithChecksPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP};
const MovegenPhaseT QsearchWithoutChecksPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_QCAPTURES, PH_STOP};
@ -79,7 +80,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
if (p.is_check())
phasePtr = EvasionsPhaseTable;
else if (d > Depth(0))
phasePtr = MainSearchPhaseTable;
phasePtr = useNullMove ? MainSearchPhaseTable : MainSearchNoNullPhaseTable;
else if (d == Depth(0))
phasePtr = QsearchWithChecksPhaseTable;
else
@ -116,7 +117,7 @@ Move MovePicker::get_next_move() {
switch (*phasePtr) {
case PH_NULL_MOVE:
break;
return MOVE_NULL;
case PH_TT_MOVES:
movesPicked = 0; // This is used as index to ttMoves[]

83
src/search.cpp
View file

@ -1288,45 +1288,6 @@ namespace {
&& ok_to_do_nullmove(pos)
&& approximateEval >= beta - NullMoveMargin);
// Null move search
if (useNullMove)
{
ss[ply].currentMove = MOVE_NULL;
StateInfo st;
pos.do_null_move(st);
int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction
Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
pos.undo_null_move();
if (nullValue >= beta)
{
if (depth < 6 * OnePly)
return beta;
// Do zugzwang verification search
Value v = search(pos, ss, beta, depth-5*OnePly, ply, false, threadID);
if (v >= beta)
return beta;
} else {
// The null move failed low, which means that we may be faced with
// some kind of threat. If the previous move was reduced, check if
// the move that refuted the null move was somehow connected to the
// move which was reduced. If a connection is found, return a fail
// low score (which will cause the reduced move to fail high in the
// parent node, which will trigger a re-search with full depth).
if (nullValue == value_mated_in(ply + 2))
mateThreat = true;
ss[ply].threatMove = ss[ply + 1].currentMove;
if ( depth < ThreatDepth
&& ss[ply - 1].reduction
&& connected_moves(pos, ss[ply - 1].currentMove, ss[ply].threatMove))
return beta - 1;
}
}
// Null move search not allowed, try razoring
if ( !useNullMove
&& !value_is_mate(beta)
@ -1351,7 +1312,7 @@ namespace {
// Initialize a MovePicker object for the current position, and prepare
// to search all moves.
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply], useNullMove);
Move move, movesSearched[256];
int moveCount = 0;
@ -1367,6 +1328,48 @@ namespace {
&& (move = mp.get_next_move()) != MOVE_NONE
&& !thread_should_stop(threadID))
{
// Null move search
if (move == MOVE_NULL)
{
ss[ply].currentMove = MOVE_NULL;
StateInfo st;
pos.do_null_move(st);
int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction
Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
pos.undo_null_move();
if (nullValue >= beta)
{
if (depth < 6 * OnePly)
return beta;
// Do zugzwang verification search
Value v = search(pos, ss, beta, depth-5*OnePly, ply, false, threadID);
if (v >= beta)
return beta;
} else {
// The null move failed low, which means that we may be faced with
// some kind of threat. If the previous move was reduced, check if
// the move that refuted the null move was somehow connected to the
// move which was reduced. If a connection is found, return a fail
// low score (which will cause the reduced move to fail high in the
// parent node, which will trigger a re-search with full depth).
if (nullValue == value_mated_in(ply + 2))
mateThreat = true;
ss[ply].threatMove = ss[ply + 1].currentMove;
if ( depth < ThreatDepth
&& ss[ply - 1].reduction
&& connected_moves(pos, ss[ply - 1].currentMove, ss[ply].threatMove))
return beta - 1;
}
continue;
}
assert(move_is_ok(move));
bool singleReply = (isCheck && mp.number_of_moves() == 1);