bool GraphUtils::isGraphConnected(GraphIF* const graph,
EdgeSetIF* const notHiddenEdges) {
graph->hideAllEdges();
notHiddenEdges->begin();
while (notHiddenEdges->hasNext()) {
notHiddenEdges->next()->show();
}
INFO(logger, LogBundleKey::GU_CHECK_GRAPH_CONNECTIVITY_WITH_EDGE_SET,
LogStringUtils::graphBasicDescription(graph, "\t").c_str(),
LogStringUtils::edgeSetVisualization(notHiddenEdges, "\t").c_str());
return isGraphConnected(graph);
}
void Graph<T>::generateRandomGraph(int numVertices,double density)
{
int numEdges = ceil((density *(numVertices*numVertices - numVertices))/200);
if(numEdges < (numVertices-1) || density >100)
{
cout<<"Error: Density not enough for Graph to be connected"<<endl;
return;
}
srand(time(NULL));
do
{
graph = new std::map<T,VertexNode<T>*>();
for(int i=0;i<numVertices;i++)
addVertex(i);
while(numEdges > 0)
{
addRandomEdge(numVertices);
numEdges--;
}
}while(!isGraphConnected());
}
EdgeSetIF* GraphUtils::getRandomSpanningTree(GraphIF* const graph)
throw (GraphExceptions::DisconnectedGraphException) {
EdgeSetIF * spanningTreeEdges { };
VertexCount numberOfVertices { };
EdgeCount numberOfEdgesInMST { };
std::vector<bool> discoveryArray { };
std::list<VertexIF*> vertexStack { };
VertexIF* vertex { };
VertexIdx idx { };
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_INIT,
LogStringUtils::graphBasicDescription(graph, "\t").c_str());
if (isGraphConnected(graph)) {
spanningTreeEdges = new EdgeSetImpl { };
numberOfVertices = graph->getNumberOfVertices();
numberOfEdgesInMST = numberOfVertices - 1;
discoveryArray = std::vector<bool>(numberOfVertices, false);
idx = std::rand() % numberOfVertices;
discoveryArray[idx] = true; //root
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_ROOT, idx);
for (idx = 0; idx < numberOfVertices; idx += 1) {
if (spanningTreeEdges->size() == numberOfEdgesInMST) {
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_BREAK, idx);
break;
}
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_CONSTRUCT_PATH, idx);
vertexStack.clear();
vertex = graph->getVertexByIdx(idx);
if (discoveryArray.at(vertex->getVertexIdx()) == false) {
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_NOT_DISCOVERED,
idx);
vertexStack.push_back(vertex);
do {
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_BUILD_PATH,
vertex->getVertexIdx(),
LogStringUtils::vertexOutputEdges(vertex, "\t").c_str());
vertex = vertex->getRandomSuccessor();
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_ADD_TO_PATH,
vertex->getVertexIdx());
vertexStack.push_back(vertex);
} while (discoveryArray.at(vertex->getVertexIdx()) == false);
INFO(logger,
LogBundleKey::GU_RND_MST_SEARCH_ADD_EDGES_FROM_PATH,
vertexStack.back()->getVertexIdx(), idx,
vertexStack.size() - 1);
vertex = vertexStack.back();
vertexStack.pop_back();
while (!vertexStack.empty()) {
if (spanningTreeEdges->size() == numberOfEdgesInMST) {
vertexStack.clear();
break;
}
if (discoveryArray[vertexStack.back()->getVertexIdx()]
== false) {
discoveryArray[vertexStack.back()->getVertexIdx()] =
true;
INFO(logger,
LogBundleKey::GU_RND_MST_SEARCH_ADD_EDGE_FROM_PATH,
vertexStack.back()->getVertexIdx(),
vertex->getVertexIdx(),
LogStringUtils::edgeVisualization(
vertexStack.back()->findOutputEdge(
vertex), "\t").c_str());
spanningTreeEdges->push_back(
vertex->findOutputEdge(vertexStack.back()));
}
vertex = vertexStack.back();
vertexStack.pop_back();
}
}
INFO(logger, LogBundleKey::GU_RND_MST_SEARCH_CONSTRUCT_PATH_END,
idx);
}
INFO(logger, LogBundleKey::GU_RND_MST_FOUND,
LogStringUtils::edgeSetVisualization(spanningTreeEdges, "\t").c_str());
return spanningTreeEdges;
} else {
WARN_NOARG(logger, LogBundleKey::GU_RND_MST_GRAPH_DISCONNECTED);
throw GraphExceptions::DisconnectedGraphException();
}
}
