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Code Issues Releases Wiki Activity

Introduce NullStatus enum

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No functional change

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Joona Kiiski 2010-04-11 20:21:26 +03:00 • committed by Marco Costalba
parent 81ae7cad2d
commit f3809f2a18
1 changed files with 27 additions and 20 deletions
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47
src/search.cpp
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@ -104,6 +104,13 @@ namespace {
};
// FIXME: document me
enum NullStatus {
ALLOW_NULLMOVE,
FORBID_NULLMOVE,
VERIFY_NULLMOVE
};
// RootMove struct is used for moves at the root at the tree. For each
// root move, we store a score, a node count, and a PV (really a refutation
@ -281,7 +288,7 @@ namespace {
Value id_loop(const Position& pos, Move searchMoves[]);
Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
Value search_pv(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID, Move excludedMove = MOVE_NONE);
Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, NullStatus nullStatus, int threadID, Move excludedMove = MOVE_NONE);
Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
void sp_search(SplitPoint* sp, int threadID);
void sp_search_pv(SplitPoint* sp, int threadID);
@ -886,7 +893,7 @@ namespace {
if (ss[0].reduction)
{
// Reduced depth non-pv search using alpha as upperbound
value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0);
value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, ALLOW_NULLMOVE, 0);
doFullDepthSearch = (value > alpha);
}
}
@ -896,7 +903,7 @@ namespace {
{
// Full depth non-pv search using alpha as upperbound
ss[0].reduction = Depth(0);
value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
value = -search(pos, ss, -alpha, newDepth, 1, ALLOW_NULLMOVE, 0);
// If we are above alpha then research at same depth but as PV
// to get a correct score or eventually a fail high above beta.
@ -1131,7 +1138,7 @@ namespace {
if (abs(ttValue) < VALUE_KNOWN_WIN)
{
Value excValue = search(pos, ss, ttValue - SingularExtensionMargin, depth / 2, ply, false, threadID, move);
Value excValue = search(pos, ss, ttValue - SingularExtensionMargin, depth / 2, ply, FORBID_NULLMOVE, threadID, move);
if (excValue < ttValue - SingularExtensionMargin)
ext = OnePly;
@ -1167,7 +1174,7 @@ namespace {
ss[ply].reduction = pv_reduction(depth, moveCount);
if (ss[ply].reduction)
{
value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID);
value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, ALLOW_NULLMOVE, threadID);
doFullDepthSearch = (value > alpha);
}
}
@ -1176,7 +1183,7 @@ namespace {
if (doFullDepthSearch)
{
ss[ply].reduction = Depth(0);
value = -search(pos, ss, -alpha, newDepth, ply+1, true, threadID);
value = -search(pos, ss, -alpha, newDepth, ply+1, ALLOW_NULLMOVE, threadID);
// Step extra. pv search (only in PV nodes)
if (value > alpha && value < beta)
@ -1251,7 +1258,7 @@ namespace {
// search() is the search function for zero-width nodes.
Value search(Position& pos, SearchStack ss[], Value beta, Depth depth,
int ply, bool allowNullmove, int threadID, Move excludedMove) {
int ply, NullStatus nullStatus, int threadID, Move excludedMove) {
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
assert(ply >= 0 && ply < PLY_MAX);
@ -1299,7 +1306,7 @@ namespace {
tte = TT.retrieve(posKey);
ttMove = (tte ? tte->move() : MOVE_NONE);
if (tte && ok_to_use_TT(tte, depth, beta, ply, allowNullmove))
if (tte && ok_to_use_TT(tte, depth, beta, ply, nullStatus == ALLOW_NULLMOVE))
{
ss[ply].currentMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
@ -1339,7 +1346,7 @@ namespace {
// Step 7. Static null move pruning
// We're betting that the opponent doesn't have a move that will reduce
// the score by more than futility_margin(depth) if we do a null move.
if ( allowNullmove
if ( nullStatus == ALLOW_NULLMOVE
&& depth < RazorDepth
&& !isCheck
&& !value_is_mate(beta)
@ -1351,7 +1358,7 @@ namespace {
// When we jump directly to qsearch() we do a null move only if static value is
// at least beta. Otherwise we do a null move if static value is not more than
// NullMoveMargin under beta.
if ( allowNullmove
if ( nullStatus == ALLOW_NULLMOVE
&& depth > OnePly
&& !isCheck
&& !value_is_mate(beta)
@ -1369,7 +1376,7 @@ namespace {
pos.do_null_move(st);
nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, FORBID_NULLMOVE, threadID);
pos.undo_null_move();
@ -1382,7 +1389,7 @@ namespace {
// Do zugzwang verification search for high depths, don't store in TT
// if search was stopped.
if ( ( depth < 6 * OnePly
|| search(pos, ss, beta, depth-5*OnePly, ply, false, threadID) >= beta)
|| search(pos, ss, beta, depth-5*OnePly, ply, FORBID_NULLMOVE, threadID) >= beta)
&& !AbortSearch
&& !TM.thread_should_stop(threadID))
{
@ -1415,7 +1422,7 @@ namespace {
&& !isCheck
&& ss[ply].eval >= beta - IIDMargin)
{
search(pos, ss, beta, depth/2, ply, false, threadID);
search(pos, ss, beta, depth/2, ply, FORBID_NULLMOVE, threadID);
ttMove = ss[ply].pv[ply];
tte = TT.retrieve(posKey);
}
@ -1457,7 +1464,7 @@ namespace {
if (abs(ttValue) < VALUE_KNOWN_WIN)
{
Value excValue = search(pos, ss, ttValue - SingularExtensionMargin, depth / 2, ply, false, threadID, move);
Value excValue = search(pos, ss, ttValue - SingularExtensionMargin, depth / 2, ply, FORBID_NULLMOVE, threadID, move);
if (excValue < ttValue - SingularExtensionMargin)
ext = OnePly;
@ -1511,7 +1518,7 @@ namespace {
ss[ply].reduction = nonpv_reduction(depth, moveCount);
if (ss[ply].reduction)
{
value = -search(pos, ss, -(beta-1), newDepth-ss[ply].reduction, ply+1, true, threadID);
value = -search(pos, ss, -(beta-1), newDepth-ss[ply].reduction, ply+1, ALLOW_NULLMOVE, threadID);
doFullDepthSearch = (value >= beta);
}
}
@ -1520,7 +1527,7 @@ namespace {
if (doFullDepthSearch)
{
ss[ply].reduction = Depth(0);
value = -search(pos, ss, -(beta-1), newDepth, ply+1, true, threadID);
value = -search(pos, ss, -(beta-1), newDepth, ply+1, ALLOW_NULLMOVE, threadID);
}
// Step 16. Undo move
@ -1870,7 +1877,7 @@ namespace {
ss[sp->ply].reduction = nonpv_reduction(sp->depth, moveCount);
if (ss[sp->ply].reduction)
{
value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, ALLOW_NULLMOVE, threadID);
doFullDepthSearch = (value >= sp->beta && !TM.thread_should_stop(threadID));
}
}
@ -1879,7 +1886,7 @@ namespace {
if (doFullDepthSearch)
{
ss[sp->ply].reduction = Depth(0);
value = -search(pos, ss, -(sp->beta - 1), newDepth, sp->ply+1, true, threadID);
value = -search(pos, ss, -(sp->beta - 1), newDepth, sp->ply+1, ALLOW_NULLMOVE, threadID);
}
// Step 16. Undo move
@ -1976,7 +1983,7 @@ namespace {
if (ss[sp->ply].reduction)
{
Value localAlpha = sp->alpha;
value = -search(pos, ss, -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
value = -search(pos, ss, -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, ALLOW_NULLMOVE, threadID);
doFullDepthSearch = (value > localAlpha && !TM.thread_should_stop(threadID));
}
}
@ -1986,7 +1993,7 @@ namespace {
{
Value localAlpha = sp->alpha;
ss[sp->ply].reduction = Depth(0);
value = -search(pos, ss, -localAlpha, newDepth, sp->ply+1, true, threadID);
value = -search(pos, ss, -localAlpha, newDepth, sp->ply+1, ALLOW_NULLMOVE, threadID);
if (value > localAlpha && value < sp->beta && !TM.thread_should_stop(threadID))
{