C++ GiSTpath::Page方法代码示例

void
MTnode::InvalidateEntry (BOOL bNew)
{
	GiSTpath path = Path ();
	if (path.Level() > 1) {  // len>=3
		MTnode *parentNode = ((MT *)Tree())->ParentNode((MTnode *)this);
		for (int i=0; i<parentNode->NumEntries(); i++) {  // search the entry in the parent's node
			MTentry *entry = (MTentry *) (*parentNode)[i].Ptr();
			if (entry->Ptr() == path.Page()) {
				if (bNew) {
					entry->Key()->distance = -MaxDist();
				}
				entry->Key()->splitted = TRUE;
				break;
			}
		}
		path.MakeParent ();
		MTnode *grandNode = ((MT *)Tree())->ParentNode(parentNode);
		for (int i=0; i<grandNode->NumEntries(); i++) {  // search the entry in the grandparent's node
			MTentry *entry = (MTentry *) (*grandNode)[i].Ptr();
			if (entry->Ptr() == path.Page()) {
				entry->SetMaxRadius(-1);
				break;
			}
		}
		((MT *)Tree())->WriteNode(parentNode);  // write parent node (in inconsistent state)
		((MT *)Tree())->WriteNode(grandNode);  // write grandparent node (to invalidate the parent's entry)
		delete parentNode;
		delete grandNode;
	}
}

void
GiST::ShortenTree()
{
	GiSTpath path;
	// Shorten the tree if necessary (This should only be done if root actually changed!)
	path.MakeRoot();
	GiSTnode *root=ReadNode(path);

	if(!root->IsLeaf()&&root->NumEntries()==1) {
		path.MakeChild((*root)[0]->Ptr());
		GiSTnode *child=ReadNode(path);

		store->Deallocate(path.Page());
		child->SetSibling(0);
		child->Path().MakeRoot();
		WriteNode(child);
		delete child;
	}
	delete root;
}

void MXTree::Split(GiSTnode **node, const GiSTentry& entry)
{
	double radii[2], dist, *dists = new double[(*node)->NumEntries()*2];
	int pageNums[2], cands[2];
	vector<vector<int>> vec(2);
	((MXTnode *)(*node))->TestPromotion(radii, &dist, pageNums, cands, dists, vec);
	if (Trade((*node)->Path().IsRoot(), radii, dist, pageNums, ((MXTnode *)(*node))->GetPageNum()+1, (*node)->NumEntries())) {
		// don't split now
		delete[] dists;
		GiSTpath oldPath = (*node)->Path();

		int startPage = ((*node)->Path().IsRoot() ? rootPage : (*node)->Path().Page());
		int pageNum = ((MXTnode *)(*node))->GetPageNum();
		((MXTfile *)store)->Deallocate(startPage, pageNum);
		startPage = ((MXTfile *)store)->Allocate(++pageNum);
		(*node)->Path().MakeSibling(startPage);
		rootPage = ((*node)->Path().IsRoot() ? startPage : rootPage);
		((MXTnode *)(*node))->SetPageNum(pageNum);
		WriteNode(*node);

		if (!(*node)->Path().IsRoot() && startPage != oldPath.Page()) {
			GiSTpath parentPath = oldPath;
			parentPath.MakeParent();
			GiSTnode *parentNode = ReadNode(parentPath);
			GiSTentry *e = parentNode->SearchPtr(oldPath.Page());
			assert(e != NULL);
			int pos = e->Position();
			e->SetPtr(startPage);
			parentNode->DeleteEntry(pos);
			parentNode->InsertBefore(*e, pos);
			WriteNode(parentNode);
			delete parentNode;
			delete e;
		}
	} else {
		// split now
		bool bLeft = false, bNewRoot = false;

		if ((*node)->Path().IsRoot()) {
			bNewRoot = true;
			(*node)->Path().MakeChild(rootPage);
			rootPage = store->Allocate();
		}

		int oldPageNum = ((MXTnode *)(*node))->GetPageNum();
		GiSTnode *node2 = ((MXTnode *)(*node))->PickSplit(cands, dists, vec);
		delete[] dists;
		int curPageNum = ((MXTnode *)(*node))->GetPageNum();
		assert(oldPageNum >= curPageNum);
		if (oldPageNum > curPageNum) {
			((MXTfile *)store)->Deallocate((*node)->Path().Page()+curPageNum, oldPageNum-curPageNum);
		}
		node2->Path().MakeSibling(((MXTfile *)store)->Allocate(((MXTnode *)node2)->GetPageNum()));

		WriteNode(*node);
		WriteNode(node2);
	
		GiSTentry *e = (*node)->SearchPtr(entry.Ptr());
		if (e != NULL) {
			bLeft = true;
			delete e;
		}
	
		GiSTentry *e1 = (*node)->Union();
		GiSTentry *e2 = node2->Union();
	
		e1->SetPtr((*node)->Path().Page());
		e2->SetPtr(node2->Path().Page());
		// Create new root if root is being split
		if (bNewRoot) {
			GiSTnode *root = NewNode(this);
			root->SetLevel((*node)->Level() + 1);
			root->InsertBefore(*e1, 0);
			root->InsertBefore(*e2, 1);
			root->Path().MakeRoot();
			WriteNode(root);
			delete root;
		} else {
			// Insert entry for N' in parent
			GiSTpath parentPath = (*node)->Path();
			parentPath.MakeParent();
			GiSTnode *parent = ReadNode(parentPath);
			// Find the entry for N in parent
			GiSTentry *e = parent->SearchPtr((*node)->Path().Page());
			assert(e != NULL);
			// Insert the new entry right after it
			int pos = e->Position();
			parent->DeleteEntry(pos);
			parent->InsertBefore(*e1, pos);
			parent->InsertBefore(*e2, pos+1);
			delete e;
			if (!parent->IsOverFull(*store)) {
				WriteNode(parent);
			} else {
				Split(&parent, bLeft? *e1: *e2);  // parent is the node which contains the entry inserted
				GiSTpage page = (*node)->Path().Page();
				(*node)->Path() = parent->Path();  // parent's path may change
				(*node)->Path().MakeChild(page);
				page = node2->Path().Page();
				node2->Path() = (*node)->Path();
//.........这里部分代码省略.........

// load this M-tree with n data using the BulkLoad algorithm [CP98]
// data is an array of n entries
// padFactor is the maximum node utilization (use 1)
// name is the name of the tree
void
MT::BulkLoad (MTentry **data, int n, double padFactor, const char *name)
{
	int size = 0;
	if (EntrySize()) {
		size = n * (sizeof(GiSTpage) + EntrySize());  // (only valid if we've fixed size entries)
	} else {
		for (int i=0; i<n; i++) {
			size += sizeof(GiSTlte) + sizeof(GiSTpage) + data[i]->CompressedLength();
		}
	}
	int totSize = size + GIST_PAGE_HEADER_SIZE + sizeof(GiSTlte);

	if (totSize > Store()->PageSize()) {  // we need to split the entries into several sub-trees
		int numEntries = (int)(Store()->PageSize()*padFactor*n) / totSize;
		int s = (int) MAX (MIN (numEntries, ceil(((float)n)/numEntries)), numEntries*MIN_UTIL);  // initial number of samples
		int nSamples, *samples = new int[s], *sizes = NULL, *ns = NULL, iter = 0, MAXITER = s * s;
		GiSTlist<double *> *distm = (GiSTlist<double *> *) calloc (s, sizeof(GiSTlist<double *>));  // relative distances between samples
		int MINSIZE = (int) (Store()->PageSize()*MIN_UTIL), addEntrySize = EntrySize() ? sizeof(GiSTpage) : sizeof(GiSTlte)+sizeof(GiSTpage);
		GiSTlist<int> *lists = NULL;  // set for each sample set
		GiSTlist<double> *dists = NULL;  // set for distance between each sample and its members
		BOOL *bSampled = new BOOL[n];  // is this entry in the samples set?

		// sampling phase
		do {
			iter++;
			if (iter > 1) {  // this is a new sampling phase
				while (!lists[0].IsEmpty()) {
					lists[0].RemoveFront ();
					dists[0].RemoveFront ();
				}
				delete []lists;
				delete []dists;
				delete []sizes;
				delete []ns;
				while (!distm[0].IsEmpty()) {
					delete []distm[0].RemoveFront();  // empty the distance list
				}
				for (int i=1; i<s; i++) {
					distm[i].front = distm[i].rear = NULL;
				}
			}
			if (iter >= MAXITER) {
				cout << "Too many loops in BulkLoad!"<<endl<<"Please select a lower minimum node utilization or a bigger node size."<<endl;
				exit(1);
			}

			for (int i=0; i<n; i++) {
				bSampled[i] = FALSE;
			}
			nSamples = 0;
			// pick s samples to create parents
			while (nSamples < s) {
				int i;
				do {
					i = PickRandom (0, n);
				} while (bSampled[i]);
				bSampled[i] = TRUE;
				samples[nSamples++] = i;
			}

			lists = new GiSTlist<int>[s];
			dists = new GiSTlist<double>[s];
			sizes = new int[s];
			ns = new int[s];
			for (int i=0; i<s; i++) {
				sizes[i] = GIST_PAGE_HEADER_SIZE + sizeof(GiSTlte);
				ns[i] = 1;
				distm[i].Prepend (new double[s]);
			}

			// compute the relative distances between samples
			for (int i=0; i<s; i++) {
				for (int j=0; j<i; j++) {
					distm[j].front->entry[i] = distm[i].front->entry[j] = data[samples[j]]->object().distance(data[samples[i]]->object());
				}
				distm[i].front->entry[i] = 0;
			}

			// assign each entry to its nearest parent
			for (int i=0; i<n; i++) {
				if (bSampled[i]) {
					int j = 0;
					for (; samples[j]!=i; j++);  // find this entry in the samples set and return position in it
					lists[j].Prepend (i);  // insert the entry in the right sample
					dists[j].Prepend (0);  // distance between sample and data[i]
					sizes[j] += addEntrySize + data[i]->CompressedLength();
				} else {  // here we optimize the distance computations (like we do in the insert algorithm)
					double *dist = new double[s];  // distance between this non-sample and samples
					dist[0] = data[samples[0]]->object().distance(data[i]->object());
					int minIndex = 0;
					for (int j=1; j<s; j++) {  // seek the nearest sample
						dist[j] = -MaxDist();
						if (fabs (data[samples[j]]->Key()->distance - data[i]->Key()->distance) >= dist[minIndex]) {  // pruning
							continue;
						}
//.........这里部分代码省略.........