void TForestFire::InfectRnd(const int& NInfect) {
IAssert(NInfect < Graph->GetNodes());
TIntV NIdV(Graph->GetNodes(), 0);
for (TNGraph::TNodeI NI = Graph->BegNI(); NI < Graph->EndNI(); NI++) {
NIdV.Add(NI.GetId()); }
NIdV.Shuffle(Rnd);
InfectNIdV.Gen(NInfect, 0);
for (int i = 0; i < NInfect; i++) {
InfectNIdV.Add(NIdV[i]); }
}
/// Barabasi-Albert model of scale-free graphs.
/// The graph has power-law degree distribution.
/// See: Emergence of scaling in random networks by Barabasi and Albert.
/// URL: http://arxiv.org/abs/cond-mat/9910332
PUNGraph GenPrefAttach(const int& Nodes, const int& NodeOutDeg, TRnd& Rnd) {
PUNGraph GraphPt = PUNGraph::New();
TUNGraph& Graph = *GraphPt;
Graph.Reserve(Nodes, NodeOutDeg*Nodes);
TIntV NIdV(NodeOutDeg*Nodes, 0);
// first edge
Graph.AddNode(0); Graph.AddNode(1);
NIdV.Add(0); NIdV.Add(1);
Graph.AddEdge(0, 1);
TIntSet NodeSet;
for (int node = 2; node < Nodes; node++) {
NodeSet.Clr(false);
while (NodeSet.Len() < NodeOutDeg && NodeSet.Len() < node) {
NodeSet.AddKey(NIdV[TInt::Rnd.GetUniDevInt(NIdV.Len())]);
}
const int N = Graph.AddNode();
for (int i = 0; i < NodeSet.Len(); i++) {
Graph.AddEdge(N, NodeSet[i]);
NIdV.Add(N);
NIdV.Add(NodeSet[i]);
}
}
return GraphPt;
}
