Ejemplo n.º 1
0
node PivotMDS::getRootedPath(const Graph& G)
{
	node head = nullptr;
	NodeArray<bool> visited(G, false);
	SListPure<node> neighbors;
	// in every path there are two nodes with degree 1 and
	// each node has at most degree 2
	for(node v : G.nodes)
	{
		int degree = 0;
		visited[v] = true;
		neighbors.pushBack(v);

		for(adjEntry adj : v->adjEntries) {
			node w = adj->twinNode();
			if (!visited[w])
			{
				neighbors.pushBack(w);
				visited[w]=true;
				++degree;
			}
		}
		if (degree > 2) {
			neighbors.clear();
			return nullptr;
		}
		if (degree == 1) {
			head = v;
		}
		for(node u : neighbors) {
			visited[u] = false;
		}
		neighbors.clear();
	}
	return head;
}
Ejemplo n.º 2
0
void PlanarSPQRTree::adoptEmbedding()
{
	OGDF_ASSERT_IF(dlExtendedChecking, originalGraph().representsCombEmbedding());

	// ordered list of adjacency entries (for one original node) in all
	// skeletons (where this node occurs)
	NodeArray<SListPure<adjEntry> > adjEdges(tree());
	// copy in skeleton of current original node
	NodeArray<node> currentCopy(tree(),nullptr);
	NodeArray<adjEntry> lastAdj(tree(),nullptr);
	SListPure<node> current; // currently processed nodes

	for (node vOrig : originalGraph().nodes)
	{
		for(adjEntry adjOrig : vOrig->adjEdges)
		{
			edge            eOrig = adjOrig->theEdge();
			const Skeleton &S     = skeletonOfReal(eOrig);
			edge            eCopy = copyOfReal(eOrig);

			adjEntry adjCopy = (S.original(eCopy->source()) == vOrig) ?
				eCopy->adjSource() : eCopy->adjTarget();

			setPosInEmbedding(adjEdges,currentCopy,lastAdj,current,S,adjCopy);
		}

		for(node vT : current) {
			skeleton(vT).getGraph().sort(currentCopy[vT],adjEdges[vT]);

			adjEdges[vT].clear();
			currentCopy[vT] = nullptr;
		}

		current.clear();
	}
}
Ejemplo n.º 3
0
// separate pertinent nodes in the lists of possible different minor-types
void FindKuratowskis::splitInMinorTypes(
			const SListPure<adjEntry>& externalFacePath,
			int marker)
{
	// mark nodes, which are before stopX or behind stopY in CCW-traversal and add
	// all extern nodes strictly between stopX and stopY to list
	// externE for minor E (pertinent nodes are considered because of the
	// position of z left or right of w)
	SListConstIterator<adjEntry> itExtern;
	SListIterator<WInfo> it = k.wNodes.begin();
	node x;
	bool between = false;
	SListPure<WInfo*> infoList;
	SListIterator<WInfo*> itList;
	ExternE externEdummy;
	// compute list of externE nodes
	for (itExtern=externalFacePath.begin(); itExtern.valid(); ++itExtern) {
		x = (*itExtern)->theNode();
		if (x==k.stopX || x==k.stopY) {
			between = (between==false) ? true : false;
		} else {
			if (!between) {
				m_wasHere[x]=marker;
			} else {
				if (pBM->externallyActive(x,k.V_DFI)) {
					externEdummy.theNode = x;

					// check minor type B and save extern linkage
					if (it.valid() && (*it).w==x &&
							!m_pertinentRoots[x].empty() &&
							m_lowPoint[m_nodeFromDFI[-m_dfi[m_pertinentRoots[x].back()]]]
							< k.V_DFI) {
						WInfo& info(*it);

						// checking minor type B
						info.minorType |= WInfo::B;
						// mark extern node for later extraction
						externEdummy.startnodes.pushBack(0);
						// create externE-list
						k.externE.pushBack(externEdummy);
						// save extern linkage
						info.externEStart = k.externE.rbegin();
						info.externEEnd = k.externE.rbegin();
					} else {
						// create externE-list
						externEdummy.startnodes.clear();
						k.externE.pushBack(externEdummy);
					}

					// save for each wNode the first externally active successor
					// on the external face
					for (itList = infoList.begin(); itList.valid(); ++itList)
						(*itList)->firstExternEAfterW = x;
					infoList.clear();


				}

				// get appropriate WInfo
				if (it.valid() && (*it).w==x) {
					infoList.pushBack(&(*it));
					++it;
				}
			}
		}
	}

	// divide wNodes in different minor types
	// avoids multiple computation of the externE range
	itExtern = externalFacePath.begin();
	SListIterator<ExternE> itExternE = k.externE.begin();
	WInfo* oldInfo = NULL;
	for (it=k.wNodes.begin(); it.valid(); ++it) {
		WInfo& info(*it);

		// checking minor type A
		if (k.RReal!=k.V) info.minorType |= WInfo::A;

		// if a XYPath exists
		if (info.highestXYPath!=NULL) {
			if (m_wasHere[info.highestXYPath->front()->theNode()]==marker)
				info.pxAboveStopX = true;
			if (m_wasHere[info.highestXYPath->back()->theNode()]==marker)
				info.pyAboveStopY = true;

			// checking minor type C
			if (info.pxAboveStopX || info.pyAboveStopY)
				info.minorType |= WInfo::C;

			// checking minor type D
			if (info.zPath!=NULL) info.minorType |= WInfo::D;

			// checking minor type E
			if (!k.externE.empty()) {
				node t;

				// compute valid range of externE-nodes in linear time
				if (oldInfo!=NULL && info.highestXYPath==oldInfo->highestXYPath) {
					// found the same highestXYPath as before
					info.externEStart = oldInfo->externEStart;
					info.externEEnd = oldInfo->externEEnd;
					if (oldInfo->minorType & WInfo::E) info.minorType |= WInfo::E;
				} else {
					// compute range of a new highestXYPath
					node px;
					if (info.pxAboveStopX) px = k.stopX;
						else px = info.highestXYPath->front()->theNode();
					node py;
					if (info.pyAboveStopY) py = k.stopY;
						else py = info.highestXYPath->back()->theNode();
					while ((*itExtern)->theNode() != px) ++itExtern;
					t = (*(++itExtern))->theNode();
					node start = NULL;
					node end = NULL;
					while (t != py) {
						if (pBM->externallyActive(t,k.V_DFI)) {
							if (start==NULL) start = t;
							end = t;
						}
						t = (*(++itExtern))->theNode();
					}
					if (start != NULL) {
						while ((*itExternE).theNode != start) ++itExternE;
						info.externEStart = itExternE;
						// mark node to extract external subgraph later
						(*itExternE).startnodes.pushBack(0);
						node temp = start;
						while (temp != end) {
							temp = (*++itExternE).theNode;
							// mark node to extract external subgraph later
							(*itExternE).startnodes.pushBack(0);
						}
						info.externEEnd = itExternE;
						info.minorType |= WInfo::E;
					}
					oldInfo = &info;
				}
			}
		}

		/*
		// use this to find special kuratowski-structures
		if ((info.minorType & (WInfo::A|WInfo::B|WInfo::C|WInfo::D|WInfo::E)) ==
			(WInfo::A|WInfo::B|WInfo::C|WInfo::D|WInfo::E)) {
			char t; cin >> t;
		}
		*/
	}

	// extract the externalSubgraph of all saved externally active nodes
	// exclude the already extracted minor b-types
	#ifdef OGDF_DEBUG
	int visited = m_nodeMarker+1;
	#endif
	for (itExternE=k.externE.begin(); itExternE.valid(); ++itExternE) {
		if ((*itExternE).startnodes.empty()) continue;

		ExternE& externE(*itExternE);
		externE.startnodes.clear();
		if (m_bundles) {
			OGDF_ASSERT(m_wasHere[externE.theNode] < visited);
			extractExternalSubgraphBundles(externE.theNode,k.V_DFI,
										k.externalSubgraph,++m_nodeMarker);
		} else {
			extractExternalSubgraph(externE.theNode,k.V_DFI,externE.startnodes,
															externE.endnodes);
			SListIterator<int> itInt;
			SListPure<edge> dummy;
			for (itInt = externE.startnodes.begin(); itInt.valid(); ++itInt)
				externE.externalPaths.pushBack(dummy);
		}
	}
}
Ejemplo n.º 4
0
// extract external facepath in direction CCW and split the highest facepath
// in highest xy-paths. marker marks the node, highMarker is used to check,
// whether the node was visited before by the highest facepath traversal.
// highMarker+1 identifies the nodes that are zNodes.
void FindKuratowskis::extractExternalFacePath(
				SListPure<adjEntry>& externalFacePath,
				const ListPure<adjEntry>& highestFacePath,
				int marker,
				int highMarker)
{
	int dir = CCW;
	// x traverses the external facepath
	node x = pBM->successorWithoutShortCircuit(k.R,dir);
	externalFacePath.pushBack(pBM->beforeShortCircuitEdge(k.R,CCW));
	m_wasHere[k.R] = marker;
	while (x != k.R) {
		// set visited sign on nodes that are both on the highest and external facepath
		if (m_wasHere[x]>=highMarker) m_wasHere[x] = marker;
		externalFacePath.pushBack(pBM->beforeShortCircuitEdge(x,dir));
		x = pBM->successorWithoutShortCircuit(x,dir);
	}

	dir = CCW;
	x = pBM->successorWithoutShortCircuit(k.R,dir);
	ListConstIterator<adjEntry> highIt = highestFacePath.begin();
	OGDF_ASSERT(x == (*highIt)->theNode());
	SListPure<adjEntry> XYPathList;
	SListPure<adjEntry> zList;
	WInfo info;
	adjEntry adj = pBM->beforeShortCircuitEdge(k.R,CCW);
	adjEntry temp;
	while (x != k.R) {
		// go along the highest face path until next visited sign
		OGDF_ASSERT(adj->theNode()==x);
		if (m_wasHere[x] == marker) {
			XYPathList.clear();
			zList.clear();
			info.w = NULL;
			info.minorType = 0;
			info.highestXYPath = NULL;
			info.zPath = NULL;
			info.pxAboveStopX = false;
			info.pyAboveStopY = false;
			info.externEStart = NULL;
			info.externEEnd = NULL;
			info.firstExternEAfterW = NULL;
		}

		// push in wNodes-list
		if (pBM->pertinent(x)) {
			info.w = x;
			k.wNodes.pushBack(info);
		}

		// compute next highestXYPath
		if (m_wasHere[x] == marker &&
					m_wasHere[pBM->constSuccessorWithoutShortCircuit(x,dir)] != marker) {
			// traverse highFacePath to x
			while ((*highIt)->theNode() != x) ++highIt;
			OGDF_ASSERT(highIt.valid());
			XYPathList.pushBack(adj);
			OGDF_ASSERT((*highIt.succ())->theNode() !=
						pBM->constSuccessorWithoutShortCircuit(x,dir));

			// traverse highFacePath to next marker
			do {
				++highIt;
				if (!highIt.valid()) break;
				temp = *highIt;
				XYPathList.pushBack(temp);
				// check, if node is z-node and push one single z-node
				if (m_wasHere[temp->theNode()]==highMarker+1 && zList.empty())
					zList.pushBack(temp);
			} while (m_wasHere[temp->theNode()] != marker);

			// save highestXY-Path
			OGDF_ASSERT(!XYPathList.empty());
			k.highestXYPaths.pushBack(XYPathList);
			info.highestXYPath = &k.highestXYPaths.back();

			// compute path from zNode to V and save it
			if (!zList.empty()) {
				OGDF_ASSERT(zList.size()==1); // just one zNode for now
				temp = zList.back();
				do {
					do {
						temp = temp->cyclicSucc();
						OGDF_ASSERT(m_dfi[temp->twinNode()]==m_dfi[k.R] ||
									m_dfi[temp->twinNode()]>=m_dfi[k.RReal]);
					} while (m_edgeType[temp->theEdge()]==EDGE_BACK_DELETED);
					temp = temp->twin();
					zList.pushBack(temp);
				} while (temp->theNode() != k.R);
				k.zPaths.pushBack(zList);
				info.zPath = &k.zPaths.back();
			}
		}

		// go on
		adj = pBM->beforeShortCircuitEdge(x,dir);
		x = pBM->successorWithoutShortCircuit(x,dir);
	}
}
Ejemplo n.º 5
0
// start DFS-traversal
void BoyerMyrvoldInit::computeDFS()
{
	// compute random edge costs
	EdgeArray<int> costs;
	EdgeComparer comp;

	if(m_randomness > 0 && m_edgeCosts != nullptr) {
		costs.init(m_g);

		int minCost = std::numeric_limits<int>::max();
		int maxCost = std::numeric_limits<int>::min();

		for(edge e : m_g.edges) {
			minCost = min(minCost, (*m_edgeCosts)[e]);
			maxCost = min(maxCost, (*m_edgeCosts)[e]);
		}

		std::uniform_real_distribution<> urd(-1, 1);
		for(edge e : m_g.edges) {
			costs[e] = minCost + (int)((1 - m_randomness) * ((*m_edgeCosts)[e] - minCost) + m_randomness * (maxCost - minCost) * urd(m_rand));
		}

		comp.setCosts(&costs);
	} else if(m_edgeCosts != nullptr) {
		comp.setCosts(m_edgeCosts);
	}

	StackPure<adjEntry> stack;
	int nextDFI = 1;
	const int numberOfNodes = m_g.numberOfNodes();

	SListPure<adjEntry> adjList;
	SListPure<node> list;
	m_g.allNodes(list);

	// get random dfs-tree, if wanted
	if (m_randomness > 0) {
		list.permute();
	}

	for (node v : list) {
		if (v->degree() == 0) {
			m_dfi[v] = nextDFI;
			m_leastAncestor[v] = nextDFI;
			m_nodeFromDFI[nextDFI] = v;
			++nextDFI;
		} else {
			adjList.clear();
			m_g.adjEntries(v, adjList);
			adjList.quicksort(comp);
			m_g.sort(v, adjList);
			stack.push(v->firstAdj());
		}
	}

	while (nextDFI <= numberOfNodes) {
		OGDF_ASSERT(!stack.empty());
		adjEntry prnt = stack.pop();
		node v = prnt->theNode();
		// check, if node v was visited before.
		if (m_dfi[v] != 0) continue;
		// parentNode=nullptr on first node on connected component
		node parentNode = prnt->twinNode();
		if (m_dfi[parentNode] == 0) parentNode = nullptr;

		// if not, mark node as visited and initialize NodeArrays
		m_dfi[v] = nextDFI;
		m_leastAncestor[v] = nextDFI;
		m_nodeFromDFI[nextDFI] = v;
		++nextDFI;

		// push all adjacent nodes onto stack
		for(adjEntry adj : v->adjEdges) {
			edge e = adj->theEdge();
			if (adj == prnt && parentNode != nullptr) continue;

			// check for self-loops and dfs- and dfs-parallel edges
			node w = adj->twinNode();
			if (m_dfi[w] == 0) {
				m_edgeType[e] = EDGE_DFS;
				m_adjParent[w] = adj;
				m_link[CW][w] = adj;
				m_link[CCW][w] = adj;

				// found new dfs-edge: preorder
				stack.push(adj->twin());
			} else if (w == v) {
				// found self-loop
				m_edgeType[e] = EDGE_SELFLOOP;
			} else {
				// node w already has been visited and is an dfs-ancestor of v
				OGDF_ASSERT(m_dfi[w] < m_dfi[v]);
				if (w == parentNode) {
					// found parallel edge of dfs-parent-edge
					m_edgeType[e] = EDGE_DFS_PARALLEL;
				} else {
					// found backedge
					m_edgeType[e] = EDGE_BACK;
					// set least Ancestor
					if (m_dfi[w] < m_leastAncestor[v])
						m_leastAncestor[v] = m_dfi[w];
				}
			}
		}
	}
}