// Loads a (directed, undirected or multi) graph from a text file InFNm with 1 node and all its edges in a single line.
void IOConnList() {
const int NNodes = 500;
const int NEdges = 2000;
const char *FName = "demo.graph.dat";
PNEGraph GOut, GIn;
GOut = GenRndGnm<PNEGraph>(NNodes, NEdges);
// Create graph file
FILE *F = fopen(FName, "w");
for (TNEGraph::TNodeI NI = GOut->BegNI(); NI < GOut->EndNI(); NI++) {
fprintf(F, "%d", NI.GetId());
for (int i = 0; i < NI.GetOutDeg(); i++) {
fprintf(F, " %d", NI.GetOutNId(i));
}
fprintf(F, "\n");
}
fclose(F);
// Load edge list
GIn = LoadConnList<PNEGraph>(FName);
PrintGStats("ConnList - Out", GOut);
PrintGStats("ConnList - In", GIn);
}
// Save and load directed, undirected and multi-graphs, where node names are strings
void IOEdgeListStr() {
const int NNodes = 1000;
const int NEdges = 5000;
const char *FName = "demo.graph.dat";
PNEGraph GOut, GIn; // Can also be PUNGraph or PNGraph
GOut = GenRndGnm<PNEGraph>(NNodes, NEdges);
// Output nodes as random strings
TIntStrH OutNIdStrH;
TStrHash<TInt> OutStrNIdH;
// Generate unique random strings for graph
TStr RandStr;
for (TNEGraph::TNodeI NI = GOut->BegNI(); NI < GOut->EndNI(); NI++) {
do {
RandStr.Clr();
TInt RandLen = TInt::Rnd.GetUniDevInt(5, 30);
for (int i = 0; i < RandLen; i++) {
TStr RandChar(TInt::Rnd.GetUniDevInt(33, 126));
RandStr += RandChar;
}
}
while (OutStrNIdH.IsKey(RandStr) || RandStr[0] == '#'); // Not unique or starts with comment
OutNIdStrH.AddDat(NI.GetId(), RandStr);
OutStrNIdH.AddDat(RandStr, NI.GetId());
}
// Create graph file
FILE *F = fopen(FName, "w");
for (TNEGraph::TEdgeI EI = GOut->BegEI(); EI < GOut->EndEI(); EI++) {
TInt Src = EI.GetSrcNId();
TInt Dst = EI.GetDstNId();
fprintf(F, "%s %s\n", OutNIdStrH[Src].CStr(), OutNIdStrH[Dst].CStr());
}
fclose(F);
// Load edge list of strings
TStrHash<TInt> InStrToNIdH;
GIn = LoadEdgeListStr<PNEGraph>(FName, 0, 1, InStrToNIdH);
PrintGStats<PNEGraph>("EdgeListStr - Out", GOut);
PrintGStats<PNEGraph>("EdgeListStr - In", GIn);
}