文章目录
- [1 最大化攻击者/最小化防守者排序](#1 最大化攻击者/最小化防守者排序)
- [2 置换表启发](#2 置换表启发)
- [3 杀手表启发](#3 杀手表启发)
- [4 历史表启发](#4 历史表启发)
- 历史表以及杀手表的维护
启发式搜索的姿势千奇百怪，本文只讨论一下几种
cpp
//搜索空间
#define Search_Space_MVA 0 //最优价值攻击者[分数最大]
#define Search_Space_MCP 1 //最优棋型
#define Search_Space_MHT 2 //历史表排序
#define Search_Space_MKT 3 //杀手表排序
#define Search_Space_MT 4 //综合技术[MVA + MHT + MKT + 置换表]
#define Search_Space_FS 5 //第一手生成策略1 最大化攻击者/最小化防守者排序
这里就是最简单对于当前节点棋盘分数/分数的增长量进行排序。得分越高，出现越靠前。
cpp
//视角为 evalPlayer
void GameBoard::getSearchSpaceAroundStonesMaxValuableAttacter(QList<MPoint> &searchVectors,
QList<MPoint> &seachSpace,
MPlayerType evalPlayer, MPlayerType searchPlayer,
quint8 searchType /* = MINIMAX_SEARCH*/) {
bool maximizingPlayer = evalPlayer == searchPlayer;
int cutLength = getSearchCutLength(seachSpace, maximizingPlayer, searchType);
QList<int> searchVectorsScores;
searchVectors.reserve(cutLength);
searchVectorsScores.reserve(cutLength);
quint16 savedSearchBoardPatternDirection[boardSize][boardSize];
int minScore = INT_MAX; // 记录最小分数
for (const auto& s : seachSpace) {
quint64 key = zobristSearchHash.generateHash(s, PLAYER_NONE, searchPlayer);
int scoreCur;
if (!zobristSearchHash.getLeafTable(searchPlayer, scoreCur, key)) {
setSearchBoard(s, searchPlayer, savedSearchBoardPatternDirection); // 模拟落子
scoreCur = evaluateBoard(searchPlayer);
setSearchBoard(s, PLAYER_NONE, savedSearchBoardPatternDirection); // 撤销模拟落子
}
if (scoreCur <= minScore && searchVectors.size() >= cutLength) {
continue; // 如果当前分数不够高且列表已满，跳过
}
// 插入排序
int insertPos = 0;
for (; insertPos < qMin(searchVectors.size(), cutLength); ++insertPos) {
if (scoreCur > searchVectorsScores[insertPos]) {
break;
}
}
if (insertPos < cutLength) {
searchVectors.insert(insertPos, s);
searchVectorsScores.insert(insertPos, scoreCur);
if (searchVectors.size() > cutLength) {
searchVectors.removeLast(); // 移除最小分数的元素
searchVectorsScores.removeLast();
}
minScore = searchVectorsScores.last(); // 更新最小分数
}
}
// sortSearchResultByCoference(searchVectors, searchHash, maximizingPlayer, searchType);
}2 置换表启发
置换表保存了搜索过程中最优价值的节点信息，如果发现当前搜索状态在置换表，那么这一状态应该率先被搜索。
cpp
//返回的值:[0,id-1]是使用历史表启发后的结果
int GameBoard::sortMoveBySearchHistoryTable(QVector<MPoint> &searchVector,quint8 startPosition/*=0*/, quint8 searchType/*=minimax_search*/)
{
Q_UNUSED(searchType);
if(!globalParam::utilGameSetting.IsOpenSearchHistoryTable) return startPosition;
QReadLocker locker(&globalParam::historyTableLock);
std::sort(searchVector.begin() + startPosition, searchVector.end(), [](const MPoint &a, const MPoint &b) {
return globalParam::historyTable[a.x()][a.y()] > globalParam::historyTable[b.x()][b.y()];
});
//只保留有值点
for(;startPosition < searchVector.size(); startPosition ++){
if(globalParam::historyTable[searchVector.at(startPosition).x()][searchVector.at(startPosition).y()] == 0) break;
}
return startPosition;
}3 杀手表启发
杀手表保存了搜索过程中某一指定搜索深度下各个节点的剪枝信息。搜索过程中，在因为某节点产生的剪枝次数越多，这个值也就越大。
cpp
//返回的值:[0,id-1]是使用杀手表启发后的结果
int GameBoard::sortMoveBySearchKillerTable(QVector<MPoint> &searchVector, quint8 startPosition/*=0*/, quint8 searchType/*=minimax_search*/)
{
Q_UNUSED(searchType);
if(!globalParam::utilGameSetting.IsOpenKillerTable) return startPosition;
QReadLocker locker(&globalParam::killerTableLock);
int depth = searchSpacePlayers.size();
std::sort(searchVector.begin() + startPosition, searchVector.end(), [depth](const MPoint &a, const MPoint &b) {
return globalParam::killerTable[depth][UtilGetMPointPosID(a)] > globalParam::killerTable[depth][UtilGetMPointPosID(b)];
});
//只保留有值点
for(;startPosition < searchVector.size(); startPosition ++){
if(globalParam::killerTable[depth][UtilGetMPointPosID(searchVector.at(startPosition))] == 0) break;
}
return startPosition;
}4 历史表启发
类似于杀手表，但是历史表忽略了搜索深度信息。只要在搜索过程中因为某一节点产生了剪枝，这个节点的价值就会变大。
cpp
//返回的值:[0,id-1]是使用历史表启发后的结果
int GameBoard::sortMoveBySearchHistoryTable(QVector<MPoint> &searchVector,quint8 startPosition/*=0*/, quint8 searchType/*=minimax_search*/)
{
Q_UNUSED(searchType);
if(!globalParam::utilGameSetting.IsOpenSearchHistoryTable) return startPosition;
QReadLocker locker(&globalParam::historyTableLock);
std::sort(searchVector.begin() + startPosition, searchVector.end(), [](const MPoint &a, const MPoint &b) {
return globalParam::historyTable[a.x()][a.y()] > globalParam::historyTable[b.x()][b.y()];
});
//只保留有值点
for(;startPosition < searchVector.size(); startPosition ++){
if(globalParam::historyTable[searchVector.at(startPosition).x()][searchVector.at(startPosition).y()] == 0) break;
}
return startPosition;
}历史表以及杀手表的维护
杀手表和历史表的方法类似，这里仅提供杀手表的维护过程。
初始化
cpp
QReadWriteLock globalParam::killerTableLock;
int globalParam::killerTable[GameSetting::BoardSize * GameSetting::BoardSize + 1][GameSetting::BoardSize * GameSetting::BoardSize] = {{0}};追加杀手表项
cpp
//追加杀手表表项
//depth:表示距离叶子的深度
void GameBoard::appendSearchKillerTable(const MPoint &position, int depth, quint8 NABSearchHashFlag)
{
if(!globalParam::utilGameSetting.IsOpenKillerTable) return;
QWriteLocker locker(&globalParam::killerTableLock);
//随着搜索的加深，逐渐靠近叶子节点，depth的值逐步变小，对于历史表的贡献也在变小
if(NABSearchHashFlag == hashfLowerBound){
globalParam::killerTable[searchSpacePlayers.size()][UtilGetMPointPosID(position)] += depth * depth;
}
}清空杀手表
cpp
//清楚所有的杀手表
void GameBoard::clearSearchKillerTable()
{
if(!globalParam::utilGameSetting.IsOpenKillerTable) return;
QWriteLocker locker(&globalParam::killerTableLock);
//全部置零清除杀手表
for(int row = 0;row < boardSizeSquare + 1; ++row){
for(int col = 0; col < boardSizeSquare; ++col){
globalParam::killerTable[row][col] = 0;
}
}
// //使用累积影响的方式清除杀手表
// for(int row = 0;row < boardSizeSquare + 1; ++row){
// for(int col = 0; col < boardSizeSquare; ++col){
// globalParam::killerTable[row][col] = globalParam::historyTable[row][col] >> 2;
// }
// }
}