C++ (Cpp) HarmlessPruning Examples

Example #1

File: search.cpp Project: QiuleiWang/eleeye

/* 主要变例完全搜索例程，和零窗口完全搜索的区别有以下几点：
 *
 * 1. 启用内部迭代加深启发；
 * 2. 不使用有负面影响的裁剪；
 * 3. Alpha-Beta边界判定复杂；
 * 4. PV结点要获取主要变例；
 * 5. 考虑PV结点处理最佳着法的情况。
 */
static int SearchPV(int vlAlpha, int vlBeta, int nDepth, uint16_t *lpwmvPvLine) {
  int nNewDepth, nHashFlag, vlBest, vl;
  int mvBest, mvHash, mv, mvEvade;
  MoveSortStruct MoveSort;
  uint16_t wmvPvLine[LIMIT_DEPTH];
  // 完全搜索例程包括以下几个步骤：

  // 1. 在叶子结点处调用静态搜索；
  *lpwmvPvLine = 0;
  if (nDepth <= 0) {
    __ASSERT(nDepth >= -NULL_DEPTH);
    return SearchQuiesc(Search.pos, vlAlpha, vlBeta);
  }
  Search2.nAllNodes ++;

  // 2. 无害裁剪；
  vl = HarmlessPruning(Search.pos, vlBeta);
  if (vl > -MATE_VALUE) {
    return vl;
  }

  // 3. 置换裁剪；
  vl = ProbeHash(Search.pos, vlAlpha, vlBeta, nDepth, NO_NULL, mvHash);
  if (Search.bUseHash && vl > -MATE_VALUE) {
    // 由于PV结点不适用置换裁剪，所以不会发生PV路线中断的情况
    return vl;
  }

  // 4. 达到极限深度，直接返回评价值；
  __ASSERT(Search.pos.nDistance > 0);
  if (Search.pos.nDistance == LIMIT_DEPTH) {
    return Evaluate(Search.pos, vlAlpha, vlBeta);
  }
  __ASSERT(Search.pos.nDistance < LIMIT_DEPTH);

  // 5. 中断调用；
  Search2.nMainNodes ++;
  vlBest = -MATE_VALUE;
  if ((Search2.nMainNodes & Search.nCountMask) == 0 && Interrupt()) {
    return vlBest;
  }

  // 6. 内部迭代加深启发；
  if (nDepth > IID_DEPTH && mvHash == 0) {
    __ASSERT(nDepth / 2 <= nDepth - IID_DEPTH);
    vl = SearchPV(vlAlpha, vlBeta, nDepth / 2, wmvPvLine);
    if (vl <= vlAlpha) {
      vl = SearchPV(-MATE_VALUE, vlBeta, nDepth / 2, wmvPvLine);
    }
    if (Search2.bStop) {
      return vlBest;
    }
    mvHash = wmvPvLine[0];
  }

  // 7. 初始化；
  mvBest = 0;
  nHashFlag = HASH_ALPHA;
  if (Search.pos.LastMove().ChkChs > 0) {
    // 如果是将军局面，那么生成所有应将着法；
    mvEvade = MoveSort.InitEvade(Search.pos, mvHash, Search2.wmvKiller[Search.pos.nDistance]);
  } else {
    // 如果不是将军局面，那么使用正常的着法列表。
    MoveSort.InitFull(Search.pos, mvHash, Search2.wmvKiller[Search.pos.nDistance]);
    mvEvade = 0;
  }

  // 8. 按照"MoveSortStruct::NextFull()"例程的着法顺序逐一搜索；
  while ((mv = MoveSort.NextFull(Search.pos)) != 0) {
    if (Search.pos.MakeMove(mv)) {

      // 9. 尝试选择性延伸；
      nNewDepth = (Search.pos.LastMove().ChkChs > 0 || mvEvade != 0 ? nDepth : nDepth - 1);

      // 10. 主要变例搜索；
      if (vlBest == -MATE_VALUE) {
        vl = -SearchPV(-vlBeta, -vlAlpha, nNewDepth, wmvPvLine);
      } else {
        vl = -SearchCut(-vlAlpha, nNewDepth);
        if (vl > vlAlpha && vl < vlBeta) {
          vl = -SearchPV(-vlBeta, -vlAlpha, nNewDepth, wmvPvLine);
        }
      }
      Search.pos.UndoMakeMove();
      if (Search2.bStop) {
        return vlBest;
      }

      // 11. Alpha-Beta边界判定；
      if (vl > vlBest) {
        vlBest = vl;
        if (vl >= vlBeta) {
          mvBest = mv;
          nHashFlag = HASH_BETA;
          break;
        }
        if (vl > vlAlpha) {
          vlAlpha = vl;
          mvBest = mv;
          nHashFlag = HASH_PV;
          AppendPvLine(lpwmvPvLine, mv, wmvPvLine);
        }
      }
    }
  }

  // 12. 更新置换表、历史表和杀手着法表。
  if (vlBest == -MATE_VALUE) {
    __ASSERT(Search.pos.IsMate());
    return Search.pos.nDistance - MATE_VALUE;
  } else {
    RecordHash(Search.pos, nHashFlag, vlBest, nDepth, mvEvade == 0 ? mvBest : mvEvade);
    if (mvBest != 0 && !MoveSort.GoodCap(Search.pos, mvBest)) {
      SetBestMove(mvBest, nDepth, Search2.wmvKiller[Search.pos.nDistance]);
    }
    return vlBest;
  }
}

Example #2

File: search.cpp Project: QiuleiWang/eleeye

// 零窗口完全搜索例程
static int SearchCut(int vlBeta, int nDepth, bool bNoNull = false) {
  int nNewDepth, vlBest, vl;
  int mvHash, mv, mvEvade;
  MoveSortStruct MoveSort;
  // 完全搜索例程包括以下几个步骤：

  // 1. 在叶子结点处调用静态搜索；
  if (nDepth <= 0) {
    __ASSERT(nDepth >= -NULL_DEPTH);
    return SearchQuiesc(Search.pos, vlBeta - 1, vlBeta);
  }
  Search2.nAllNodes ++;

  // 2. 无害裁剪；
  vl = HarmlessPruning(Search.pos, vlBeta);
  if (vl > -MATE_VALUE) {
    return vl;
  }

  // 3. 置换裁剪；
  vl = ProbeHash(Search.pos, vlBeta - 1, vlBeta, nDepth, bNoNull, mvHash);
  if (Search.bUseHash && vl > -MATE_VALUE) {
    return vl;
  }

  // 4. 达到极限深度，直接返回评价值；
  if (Search.pos.nDistance == LIMIT_DEPTH) {
    return Evaluate(Search.pos, vlBeta - 1, vlBeta);
  }
  __ASSERT(Search.pos.nDistance < LIMIT_DEPTH);

  // 5. 中断调用；
  Search2.nMainNodes ++;
  vlBest = -MATE_VALUE;
  if ((Search2.nMainNodes & Search.nCountMask) == 0 && Interrupt()) {
    return vlBest;
  }

  // 6. 尝试空着裁剪；
  if (Search.bNullMove && !bNoNull && Search.pos.LastMove().ChkChs <= 0 && Search.pos.NullOkay()) {
    Search.pos.NullMove();
    vl = -SearchCut(1 - vlBeta, nDepth - NULL_DEPTH - 1, NO_NULL);
    Search.pos.UndoNullMove();
    if (Search2.bStop) {
      return vlBest;
    }

    if (vl >= vlBeta) {
      if (Search.pos.NullSafe()) {
        // a. 如果空着裁剪不带检验，那么记录深度至少为(NULL_DEPTH + 1)；
        RecordHash(Search.pos, HASH_BETA, vl, MAX(nDepth, NULL_DEPTH + 1), 0);
        return vl;
      } else if (SearchCut(vlBeta, nDepth - NULL_DEPTH, NO_NULL) >= vlBeta) {
        // b. 如果空着裁剪带检验，那么记录深度至少为(NULL_DEPTH)；
        RecordHash(Search.pos, HASH_BETA, vl, MAX(nDepth, NULL_DEPTH), 0);
        return vl;
      }
    }
  }

  // 7. 初始化；
  if (Search.pos.LastMove().ChkChs > 0) {
    // 如果是将军局面，那么生成所有应将着法；
    mvEvade = MoveSort.InitEvade(Search.pos, mvHash, Search2.wmvKiller[Search.pos.nDistance]);
  } else {
    // 如果不是将军局面，那么使用正常的着法列表。
    MoveSort.InitFull(Search.pos, mvHash, Search2.wmvKiller[Search.pos.nDistance]);
    mvEvade = 0;
  }

  // 8. 按照"MoveSortStruct::NextFull()"例程的着法顺序逐一搜索；
  while ((mv = MoveSort.NextFull(Search.pos)) != 0) {
    if (Search.pos.MakeMove(mv)) {

      // 9. 尝试选择性延伸；
      nNewDepth = (Search.pos.LastMove().ChkChs > 0 || mvEvade != 0 ? nDepth : nDepth - 1);

      // 10. 零窗口搜索；
      vl = -SearchCut(1 - vlBeta, nNewDepth);
      Search.pos.UndoMakeMove();
      if (Search2.bStop) {
        return vlBest;
      }

      // 11. 截断判定；
      if (vl > vlBest) {
        vlBest = vl;
        if (vl >= vlBeta) {
          RecordHash(Search.pos, HASH_BETA, vlBest, nDepth, mv);
          if (!MoveSort.GoodCap(Search.pos, mv)) {
            SetBestMove(mv, nDepth, Search2.wmvKiller[Search.pos.nDistance]);
          }
          return vlBest;
        }
      }
    }
  }

  // 12. 不截断措施。
  if (vlBest == -MATE_VALUE) {
    __ASSERT(Search.pos.IsMate());
    return Search.pos.nDistance - MATE_VALUE;
  } else {
    RecordHash(Search.pos, HASH_ALPHA, vlBest, nDepth, mvEvade);
    return vlBest;
  }
}

Example #3

File: search.cpp Project: QiuleiWang/eleeye

// 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;
  }
}

Example #4

File: search.cpp Project: peteryuanpan/lazyboy

// 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;
}

Example #5

File: search.cpp Project: peteryuanpan/lazyboy

// 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];
}

Example #6

File: search.cpp Project: peteryuanpan/lazyboy

// 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;
}