//in ClusterGraph??
//is not yet recursive!!!
node collapseCluster(ClusterGraph& CG, cluster c, Graph& G)
{
OGDF_ASSERT(c->cCount() == 0)
ListIterator<node> its;
SListPure<node> collaps;
//we should check here if not empty
node robinson = (*(c->nBegin()));
for (its = c->nBegin(); its.valid(); its++)
collaps.pushBack(*its);
CG.collaps(collaps, G);
if (c != CG.rootCluster())
CG.delCluster(c);
return robinson;
}
//todo: is called only once, but could be sped up the same way as the co-conn check
void MaxCPlanarMaster::clusterConnection(cluster c, GraphCopy &gc, double &upperBoundC) {
// For better performance, a node array is used to indicate which nodes are contained
// in the currently considered cluster.
NodeArray<bool> vInC(gc,false);
// First check, if the current cluster \a c is a leaf cluster.
// If so, compute the number of edges that have at least to be added
// to make the cluster induced graph connected.
if (c->cCount()==0) { //cluster \a c is a leaf cluster
GraphCopy *inducedC = new GraphCopy((const Graph&)gc);
List<node> clusterNodes;
c->getClusterNodes(clusterNodes); // \a clusterNodes now contains all (original) nodes of cluster \a c.
for (node w : clusterNodes) {
vInC[gc.copy(w)] = true;
}
// Delete all nodes from \a inducedC that do not belong to the cluster,
// in order to obtain the cluster induced graph.
node v = inducedC->firstNode();
while (v!=nullptr) {
node w = v->succ();
if (!vInC[inducedC->original(v)]) inducedC->delNode(v);
v = w;
}
// Determine number of connected components of cluster induced graph.
//Todo: check could be skipped
if (!isConnected(*inducedC)) {
NodeArray<int> conC(*inducedC);
int nCC = connectedComponents(*inducedC,conC);
//at least #connected components - 1 edges have to be added.
upperBoundC -= (nCC-1)*m_largestConnectionCoeff;
}
delete inducedC;
// Cluster \a c is an "inner" cluster. Process all child clusters first.
} else { //c->cCount is != 0, process all child clusters first
for (cluster ci : c->children) {
clusterConnection(ci, gc, upperBoundC);
}
// Create cluster induced graph.
GraphCopy *inducedC = new GraphCopy((const Graph&)gc);
List<node> clusterNodes;
c->getClusterNodes(clusterNodes); //\a clusterNodes now contains all (original) nodes of cluster \a c.
for (node w : clusterNodes) {
vInC[gc.copy(w)] = true;
}
node v = inducedC->firstNode();
while (v!=nullptr) {
node w = v->succ();
if (!vInC[inducedC->original(v)]) inducedC->delNode(v);
v = w;
}
// Now collapse each child cluster to one node and determine #connected components of \a inducedC.
List<node> oChildClusterNodes;
List<node> cChildClusterNodes;
for (cluster ci : c->children) {
ci->getClusterNodes(oChildClusterNodes);
// Compute corresponding nodes of graph \a inducedC.
for (node u : oChildClusterNodes) {
node copy = inducedC->copy(gc.copy(u));
cChildClusterNodes.pushBack(copy);
}
inducedC->collapse(cChildClusterNodes);
oChildClusterNodes.clear();
cChildClusterNodes.clear();
}
// Now, check \a inducedC for connectivity.
if (!isConnected(*inducedC)) {
NodeArray<int> conC(*inducedC);
int nCC = connectedComponents(*inducedC,conC);
//at least #connected components - 1 edges have to added.
upperBoundC -= (nCC-1)*m_largestConnectionCoeff;
}
delete inducedC;
}
}//clusterConnection
//compute bag affiliation for all vertices
//store result in m_bagindex
void ClusterAnalysis::computeBags() {
const Graph &G = m_C->constGraph();
// Storage structure for results
m_bagindex.init(G);
// We use Union-Find for chunks and bags
DisjointSets<> uf;
NodeArray<int> setid(G); // Index mapping for union-find
#if 0
node* nn = new node[G.numberOfNodes()]; // dito
#endif
// Every cluster gets its index
ClusterArray<int> cind(*m_C);
// We store the lists of cluster vertices
List<node>* clists = new List<node>[m_C->numberOfClusters()];
int i = 0;
// Store index and detect the current leaf clusters
List<cluster> ccleafs;
ClusterArray<int> unprocessedChildren(*m_C); //processing below: compute bags
for(cluster c : m_C->clusters)
{
cind[c] = i++;
if (c->cCount() == 0) ccleafs.pushBack(c);
unprocessedChildren[c] = c->cCount();
}
// Now we run through all vertices, storing them in the parent lists,
// at the same time, we initialize m_bagindex
for(node v : G.nodes)
{
// setid is constant in the following
setid[v] = uf.makeSet();
// Each vertex v gets its own ClusterArray that stores v's bag index per cluster.
// See comment on use of ClusterArrays above
m_bagindex[v] = new ClusterArray<int>(*m_C,DefaultIndex, m_C->maxClusterIndex()+1);//m_C->numberOfClusters());
cluster c = m_C->clusterOf(v);
// Push vertices in parent list
clists[cind[c]].pushBack(v);
}
// Now each clist contains the direct vertex descendants
// We process the clusters bottom-up, compute the chunks
// of the leafs first. At each level, for a cluster the
// vertex lists of all children are concatenated
// (could improve this by having an array of size(#leafs)
// and concatenating only at child1), then the bags are
// updated as follows: chunks may be linked by exactly
// the edges with lca(c) ie the ones in m_lcaEdges[c],
// and bags may be built by direct child clusters that join chunks.
// While concatenating the vertex lists, we can check
// for the vertices in each child if the uf number is the same
// as the one of a first initial vertex, otherwise we join.
// First, lowest level clusters are processed: All chunks are bags
OGDF_ASSERT(!ccleafs.empty());
while (!ccleafs.empty()){
const cluster c = ccleafs.popFrontRet();
Skiplist<int*> cbags; //Stores bag indexes ocurring in c
auto storeResult = [&] {
for (node v : clists[cind[c]]) {
int theid = uf.find(setid[v]);
(*m_bagindex[v])[c] = theid;
if (!cbags.isElement(&theid)) {
cbags.add(new int(theid));
}
// push into list of outer active vertices
if (m_storeoalists && isOuterActive(v, c)) {
(*m_oalists)[c].pushBack(v);
}
}
(*m_bags)[c] = cbags.size(); // store number of bags of c
};
if (m_storeoalists){
//no outeractive vertices detected so far
(*m_oalists)[c].clear();
}
//process leafs separately
if (c->cCount() == 0) {
//Todo could use lcaEdges list here too, see below
for (node u : c->nodes)
{
for(adjEntry adj : u->adjEntries) {
node w = adj->twinNode();
if (m_C->clusterOf(w) == c)
{
uf.link(uf.find(setid[u]),uf.find(setid[w]));
}
}
}
// Now all chunks in the leaf cluster are computed
// update for parent is done in the else case
storeResult();
}
else {
// ?We construct the vertex list by concatenating
// ?the lists of the children to the current list.
// We need the lists for storing the results efficiently.
// (Should be slightly faster than to call clusterNodes each time)
// Bags are either links of chunks by edges with lca==c
// or links of chunk by child clusters.
// Edge links
for(edge e : (*m_lcaEdges)[c]) {
uf.link(uf.find(setid[e->source()]),uf.find(setid[e->target()]));
}
// Cluster links
for(cluster cc : c->children)
{
//Initial id per child cluster cc: Use value of first
//vertex, each time we encounter a different value in cc,
//we link the chunks
//add (*itcc)'s vertices to c's list
ListConstIterator<node> itvc = clists[cind[cc]].begin();
int inid;
if (itvc.valid()) inid = uf.find(setid[*itvc]);
while (itvc.valid())
{
int theid = uf.find(setid[*itvc]);
if (theid != inid)
uf.link(inid,theid);
clists[cind[c]].pushBack(*itvc);
++itvc;
}
}
storeResult();
}
// Now we update the status of the parent cluster and,
// in case all its children are processed, add it to
// the process queue.
if (c != m_C->rootCluster())
{
OGDF_ASSERT(unprocessedChildren[c->parent()] > 0);
unprocessedChildren[c->parent()]--;
if (unprocessedChildren[c->parent()] == 0) ccleafs.pushBack(c->parent());
}
}
// clean up
delete[] clists;
}
