// 静态搜索例程
static int SearchQuiesc(PositionStruct &pos, int vlAlpha, int vlBeta) {
int vlBest, vl, mv;
bool bInCheck;
MoveSortStruct MoveSort;
// 静态搜索例程包括以下几个步骤：
Search2.nAllNodes ++;
// 1. 无害裁剪；
vl = HarmlessPruning(pos, vlBeta);
if (vl > -MATE_VALUE) {
return vl;
}
#ifdef HASH_QUIESC
// 3. 置换裁剪；
vl = ProbeHashQ(pos, vlAlpha, vlBeta);
if (Search.bUseHash && vl > -MATE_VALUE) {
return vl;
}
#endif
// 4. 达到极限深度，直接返回评价值；
if (pos.nDistance == LIMIT_DEPTH) {
return Evaluate(pos, vlAlpha, vlBeta);
}
__ASSERT(Search.pos.nDistance < LIMIT_DEPTH);
// 5. 初始化；
vlBest = -MATE_VALUE;
bInCheck = (pos.LastMove().ChkChs > 0);
// 6. 对于被将军的局面，生成全部着法；
if (bInCheck) {
MoveSort.InitAll(pos);
} else {
// 7. 对于未被将军的局面，在生成着法前首先尝试空着(空着启发)，即对局面作评价；
vl = Evaluate(pos, vlAlpha, vlBeta);
__ASSERT_BOUND(1 - WIN_VALUE, vl, WIN_VALUE - 1);
__ASSERT(vl > vlBest);
if (vl >= vlBeta) {
#ifdef HASH_QUIESC
RecordHashQ(pos, vl, MATE_VALUE);
#endif
return vl;
}
vlBest = vl;
vlAlpha = MAX(vl, vlAlpha);
// 8. 对于未被将军的局面，生成并排序所有吃子着法(MVV(LVA)启发)；
MoveSort.InitQuiesc(pos);
}
// 9. 用Alpha-Beta算法搜索这些着法；
while ((mv = MoveSort.NextQuiesc(bInCheck)) != 0) {
__ASSERT(bInCheck || pos.ucpcSquares[DST(mv)] > 0);
if (pos.MakeMove(mv)) {
vl = -SearchQuiesc(pos, -vlBeta, -vlAlpha);
pos.UndoMakeMove();
if (vl > vlBest) {
if (vl >= vlBeta) {
#ifdef HASH_QUIESC
if (vl > -WIN_VALUE && vl < WIN_VALUE) {
RecordHashQ(pos, vl, MATE_VALUE);
}
#endif
return vl;
}
vlBest = vl;
vlAlpha = MAX(vl, vlAlpha);
}
}
}
// 10. 返回分值。
if (vlBest == -MATE_VALUE) {
__ASSERT(pos.IsMate());
return pos.nDistance - MATE_VALUE;
} else {
#ifdef HASH_QUIESC
if (vlBest > -WIN_VALUE && vlBest < WIN_VALUE) {
RecordHashQ(pos, vlBest > vlAlpha ? vlBest : -MATE_VALUE, vlBest);
}
#endif
return vlBest;
}
}
// Alpha-Beta 搜索
int SearchAlphaBeta ( int depth, int alpha, int beta ) {
int mv, vl;
int bmv[nBest], bvl[nBest];
ClearBmvBvl ( bmv, bvl );
int hash_type = HASH_TYPE_ALPHA;
MoveSortStruct mvsort;
if ( TimeOut() ) { // 超时
return bvl[0];
}
// 无害裁剪
vl = HarmlessPruning ();
if ( vl > - MATE_VALUE ) {
return vl;
}
// 置换裁剪
vl = QueryValueInHashTable ( depth, alpha, beta );
if ( vl > - MATE_VALUE ) {
Search.bmv[0] = QueryMoveInHashTable ( depth, alpha, beta );
Search.bvl[0] = vl;
return vl;
}
// 达到极限深度
if ( depth <= 0 ) {
return SearchQuiesc ( alpha, beta );
}
// 内部迭代加深启发
if ( depth > 2 ) {
mv = QueryMoveInHashTableWithoutLimit ();
if ( mv == 0 ) {
SearchAlphaBeta ( depth / 2, alpha, beta );
if ( TimeOut() ) { // 超时
return bvl[0];
}
}
}
// 生成着法
int nMoveNum = mvsort.InitMove ();
Search.nNode ++;
// 大搜索
while ( (mv = mvsort.NextMove()) != 0 ) {
pos.MakeMove ( mv );
int newDepth = ( pos.checked || nMoveNum == 1 ) ? depth : depth - 1;
vl = - SearchCut ( newDepth, - alpha );
if ( vl > alpha && vl < beta ) {
vl = - SearchAlphaBeta ( newDepth, -beta, -alpha );
}
pos.UndoMakeMove ();
if ( TimeOut() ) {
return bvl[0];
}
UpdateBmvBvl ( bmv, bvl, mv, vl );
if ( bvl[0] >= beta ) {
Search.nBeta ++;
hash_type = HASH_TYPE_BETA;
break;
}
if ( bvl[0] > alpha ) {
alpha = bvl[0];
hash_type = HASH_TYPE_PV;
}
}
// 最后
InsertInfoToHashTable ( depth, bmv[0], bvl[0], hash_type );
InsertHistoryTable ( bmv[0], depth );
CopyBmvBvl ( Search.bmv, Search.bvl, bmv, bvl );
return bvl[0];
}
// 静态搜索
int SearchQuiesc ( int alpha, int beta ) {
int mv, vl;
int bvl = - MATE_VALUE;
MoveSortStruct mvsort;
if ( TimeOut() ) { // 超时
return bvl;
}
// 无害裁剪
vl = HarmlessPruning ();
if ( vl > - MATE_VALUE ) {
return vl;
}
// 置换裁剪
vl = QueryValueInHashTableQC ( alpha, beta );
if ( vl > - MATE_VALUE ) {
return vl;
}
// 生成着法
if ( pos.checked ) {
mvsort.InitMove ();
}
else {
bvl = pos.Evaluate ();
if ( bvl >= beta ) {
InsertInfoToHashTableQC ( bvl, MATE_VALUE );
return bvl;
}
if ( bvl > alpha ) {
alpha = bvl;
}
mvsort.InitGoodCapMove ();
}
// 大搜索
while ( (mv = mvsort.NextMove()) != 0 ) {
pos.MakeMove (mv);
vl = - SearchQuiesc ( -beta, -alpha );
pos.UndoMakeMove ();
if ( TimeOut() ) { // 超时
return bvl;
}
if ( vl > bvl ) {
bvl = vl;
if ( bvl >= beta ) {
if ( bvl > - BAN_VALUE && bvl < BAN_VALUE ) {
InsertInfoToHashTableQC ( bvl, MATE_VALUE );
}
return vl;
}
if ( bvl > alpha ) {
alpha = bvl;
}
}
}
// 最后
if ( bvl > - BAN_VALUE && bvl < BAN_VALUE ) {
InsertInfoToHashTableQC ( bvl, bvl );
}
return bvl;
}
// 零窗口搜索
int SearchCut ( int depth, int beta, bool bNoNull = false ) {
int mv, vl;
int bmv = 0;
int bvl = - MATE_VALUE;
MoveSortStruct mvsort;
if ( TimeOut() ) { // 超时
return bvl;
}
// 无害裁剪
vl = HarmlessPruning ();
if ( vl > - MATE_VALUE ) {
return vl;
}
// 置换裁剪
vl = QueryValueInHashTable ( depth, beta - 1, beta );
if ( vl > - MATE_VALUE ) {
return vl;
}
// 达到极限深度
if ( depth <= 0 ) {
return SearchQuiesc ( beta - 1, beta );
}
// 空着裁剪 : 大切に
if ( !bNoNull && pos.checked == false && pos.NullOkay() ) {
pos.NullMove ();
vl = - SearchCut ( depth - NULL_DEPTH - 1, beta, true );
pos.UndoNullMove ();
if ( TimeOut() ) { // 超时
return bvl;
}
if ( vl >= beta ) {
if ( pos.NullSafe() ) {
InsertInfoToHashTable ( MAX(depth, NULL_DEPTH + 1), 0, vl, HASH_TYPE_BETA );
return vl;
}
else if ( SearchCut(depth - NULL_DEPTH, beta, true) >= beta ) {
InsertInfoToHashTable ( MAX(depth, NULL_DEPTH), 0, vl, HASH_TYPE_BETA );
return vl;
}
}
}
// 生成着法
int nMoveNum = mvsort.InitMove ();
Search.nNode ++;
// 大搜索
while ( (mv = mvsort.NextMove()) != 0 ) {
pos.MakeMove ( mv );
int newDepth = ( pos.checked || nMoveNum == 1 ) ? depth : depth - 1;
vl = - SearchCut ( newDepth, 1 - beta );
pos.UndoMakeMove ();
if ( TimeOut() ) { // 超时
return bvl;
}
// 边界
if ( vl > bvl ) {
bvl = vl;
bmv = mv;
if ( bvl >= beta ) {
Search.nBeta ++;
InsertInfoToHashTable ( depth, bmv, bvl, HASH_TYPE_BETA );
InsertHistoryTable ( bmv, depth );
return bvl;
}
}
}
// 最后
InsertInfoToHashTable ( depth, bmv, bvl, HASH_TYPE_ALPHA );
return bvl;
}