Method buildColoringGraph

IO/Infovis/vtkDIMACSGraphReader.cxx:332–400

============================================================================ Builder method for creating coloring problem graphs. These are undirected. nodes and edges have no weights associated with them. edges (u->v) are formatted as: e u v

// * edges (u->v) are formatted as:
//         e u v
int vtkDIMACSGraphReader::buildColoringGraph(vtkGraph* output)
{
  std::string S;
  int iEdgeU, iEdgeV;
  int currentEdgeId = 0;

  VTK_CREATE(vtkMutableUndirectedGraph, builder);
  VTK_CREATE(vtkIntArray, vertexPedigreeIds);
  VTK_CREATE(vtkIntArray, edgePedigreeIds);

  // Set up Pedigree-IDs arrays.
  vertexPedigreeIds->SetName("vertex id");
  vertexPedigreeIds->SetNumberOfTuples(this->numVerts);
  edgePedigreeIds->SetName("edge id");
  edgePedigreeIds->SetNumberOfTuples(this->numEdges);

  // Allocate Vertices in the graph builder
  for (int i = 0; i < this->numVerts; i++)
  {
    builder->AddVertex();
    vertexPedigreeIds->SetValue(i, i + 1);
  }

  // set starting edge id number.
  int baseEdgeId = 1;

  vtksys::ifstream IFP(this->FileName);
  if (IFP.is_open())
  {
    while (vtksys::SystemTools::GetLineFromStream(IFP, S))
    {
      istringstream iss(S);
      char lineType;
      iss >> lineType;
      switch (lineType)
      {
        case 'e': /* edge arc */
        {
          iss >> iEdgeU >> iEdgeV;

          if (iEdgeU == 0 || iEdgeV == 0)
          {
            vtkErrorMacro(<< "DIMACS graph vertices are numbered 1..n; 0 is not allowed");
            return 0;
          }

          builder->AddEdge(iEdgeU - 1, iEdgeV - 1);
          edgePedigreeIds->SetValue(currentEdgeId, currentEdgeId + baseEdgeId);
          currentEdgeId++;
        }
        break;
        default:
          break;
      }
    }
  }

  // Add the pedigree ids to the graph