susumu.yata
null+****@clear*****
Tue Dec 16 10:46:40 JST 2014
susumu.yata 2014-11-26 18:39:40 +0900 (Wed, 26 Nov 2014) New Revision: 326a38611f5226b0ab32c9bd64de9ee2bcb23e8b https://github.com/groonga/grnxx/commit/326a38611f5226b0ab32c9bd64de9ee2bcb23e8b Message: Specialize Sorter for Score. (#119) Modified files: lib/grnxx/impl/sorter.cpp Modified: lib/grnxx/impl/sorter.cpp (+235 -2) =================================================================== --- lib/grnxx/impl/sorter.cpp 2014-11-26 17:38:58 +0900 (e4aa32d) +++ lib/grnxx/impl/sorter.cpp 2014-11-26 18:39:40 +0900 (21ab0fe) @@ -29,6 +29,234 @@ class Node { Node *next_; }; +// --- ScoreNode --- + +struct RegularScoreComparer { + bool operator()(const Record &lhs, const Record &rhs) const { + if (lhs.score.is_na()) { + return false; + } else if (rhs.score.is_na()) { + return true; + } + return lhs.score.raw() < rhs.score.raw(); + } +}; + +struct ReverseScoreComparer { + bool operator()(const Record &lhs, const Record &rhs) const { + if (lhs.score.is_na()) { + return false; + } else if (rhs.score.is_na()) { + return true; + } + return lhs.score.raw() > rhs.score.raw(); + } +}; + +template <typename T> +class ScoreNode : public Node { + public: + using Comparer = T; + + explicit ScoreNode(SorterOrder &&order) + : Node(std::move(order)), + comparer_() {} + ~ScoreNode() = default; + + void sort(ArrayRef<Record> records, size_t begin, size_t end) { + return quick_sort(records, begin, end); + } + + private: + Comparer comparer_; + + // Sort records with ternary quick sort. + // + // Switches to insertion sort when the sorting range becomes small enough. + // + // On success, returns true. + // On failure, throws an exception. + void quick_sort(ArrayRef<Record> records, size_t begin, size_t end); + + // Sort records with insertion sort. + // + // Insertion sort should be used when there few records. + // + // On success, returns true. + // On failure, throws an exception. + void insertion_sort(ArrayRef<Record> records); + + // Choose the pivot and move it to the front. + void move_pivot_first(ArrayRef<Record> records); +}; + +template <typename T> +void ScoreNode<T>::quick_sort(ArrayRef<Record> records, + size_t begin, + size_t end) { + // Use ternary quick sort if there are enough records. + // + // TODO: Currently, the threshold is 16. + // This value should be optimized and replaced with a named constant. + while (records.size() >= 16) { + move_pivot_first(records); + const Record pivot = records[0]; + size_t left = 1; + size_t right = records.size(); + size_t pivot_left = 1; + size_t pivot_right = records.size(); + for ( ; ; ) { + // Move entries based on comparison against the pivot. + // Prior entries are moved to left. + // Less prior entries are moved to right. + // Entries which equal to the pivot are moved to the edges. + while (left < right) { + if (comparer_(pivot, records[left])) { + break; + } else if (pivot.score.match(records[left].score)) { + std::swap(records[left], records[pivot_left]); + ++pivot_left; + } + ++left; + } + while (left < right) { + --right; + if (comparer_(records[right], pivot)) { + break; + } else if (records[right].score.match(pivot.score)) { + --pivot_right; + std::swap(records[right], records[pivot_right]); + } + } + if (left >= right) { + break; + } + std::swap(records[left], records[right]); + ++left; + } + + // Move left pivot-equivalent entries to the left side of the boundary. + while (pivot_left > 0) { + --pivot_left; + --left; + std::swap(records[pivot_left], records[left]); + } + // Move right pivot-equivalent entries to the right side of the boundary. + while (pivot_right < records.size()) { + std::swap(records[pivot_right], records[right]); + ++pivot_right; + ++right; + } + + // Apply the next sort condition to the pivot-equivalent records. + if (this->next_) { + if (((right - left) >= 2) && (begin < right) && (end > left)) { + size_t next_begin = (begin < left) ? 0 : (begin - left); + size_t next_end = ((end > right) ? right : end) - left; + this->next_->sort(records.ref(left, right - left), + next_begin, next_end); + } + } + + // There are the left group and the right group. + // A recursive call is used for sorting the smaller group. + // The recursion depth is less than log_2(n) where n is the number of + // records. + // The next loop of the current call is used for sorting the larger group. + if (left < (records.size() - right)) { + if ((begin < left) && (left >= 2)) { + size_t next_end = (end < left) ? end : left; + quick_sort(records.ref(0, left), begin, next_end); + } + if (end <= right) { + return; + } + records = records.ref(right); + begin = (begin < right) ? 0 : (begin - right); + end -= right; + } else { + if ((end > right) && ((records.size() - right) >= 2)) { + size_t next_begin = (begin < right) ? 0 : (begin - right); + size_t next_end = end - right; + quick_sort(records.ref(right), next_begin, next_end); + } + if (begin >= left) { + return; + } + records = records.ref(0, left); + if (end > left) { + end = left; + } + } + } + + if (records.size() >= 2) { + insertion_sort(records); + } +} + +template <typename T> +void ScoreNode<T>::insertion_sort(ArrayRef<Record> records) { + for (size_t i = 1; i < records.size(); ++i) { + for (size_t j = i; j > 0; --j) { + if (comparer_(records[j], records[j - 1])) { + std::swap(records[j], records[j - 1]); + } else { + break; + } + } + } + + // Apply the next sorting if there are records having the same value. + if (this->next_) { + size_t begin = 0; + for (size_t i = 1; i < records.size(); ++i) { + if (records[i].score.unmatch(records[begin].score)) { + if ((i - begin) >= 2) { + this->next_->sort(records.ref(begin, i - begin), 0, i - begin); + } + begin = i; + } + } + if ((records.size() - begin) >= 2) { + this->next_->sort(records.ref(begin), 0, records.size() - begin); + } + } +} + +template <typename T> +void ScoreNode<T>::move_pivot_first(ArrayRef<Record> records) { + // Choose the median from records[1], records[1 / size], and + // records[size - 2]. + // The reason why not using records[0] and records[size - 1] is to avoid the + // worst case which occurs when the records are sorted in reverse order. + size_t first = 1; + size_t middle = records.size() / 2; + size_t last = records.size() - 2; + if (comparer_(records[first], records[middle])) { + // first < middle. + if (comparer_(records[middle], records[last])) { + // first < middle < last. + std::swap(records[0], records[middle]); + } else if (comparer_(records[first], records[last])) { + // first < last < middle. + std::swap(records[0], records[last]); + } else { + // last < first < middle. + std::swap(records[0], records[first]); + } + } else if (comparer_(records[last], records[middle])) { + // last < middle < first. + std::swap(records[0], records[middle]); + } else if (comparer_(records[last], records[first])) { + // middle < last < first. + std::swap(records[0], records[last]); + } else { + // middle < first < last. + std::swap(records[0], records[first]); + } +} + // --- BoolNode --- class BoolNode : public Node { @@ -366,8 +594,6 @@ using IntNode = ConvertNode<Int, T>; // --- FloatNode --- -// TODO: Sorter for Score should be specialized. - // NOTE: This implementation assumes IEEE754. struct RegularFloatConverter { uint64_t operator()(Float value) const { @@ -733,6 +959,13 @@ void Sorter::sort(Array<Record> *records) { } Node *Sorter::create_node(SorterOrder &&order) try { + if (order.expression->is_score()) { + if (order.type == SORTER_REGULAR_ORDER) { + return new ScoreNode<RegularScoreComparer>(std::move(order)); + } else { + return new ScoreNode<ReverseScoreComparer>(std::move(order)); + } + } switch (order.expression->data_type()) { case BOOL_DATA: { return new BoolNode(std::move(order)); -------------- next part -------------- HTML����������������������������...Download
