CDT C++ library: How to define an edge?

Question

I'm trying for a while to define an edge in CDT. Below is my code. The first function works fine, but the compilation of the second function throws this error: no matching function for call to CDT::Edge::Edge(). I also attempted numerous other trials, with no luck.

typedef CDT::V2d<double> Vertex;
typedef CDT::Edge Edge;
typedef CDT::Triangulation<double> Triangulation;

arma::umat Rcpp_delaunay(const arma::mat & points){
  Triangulation cdt(CDT::VertexInsertionOrder::AsProvided);
  size_t npoints = points.n_rows;
  std::vector<Vertex> vertices(npoints);
  for (size_t i = 0; i < npoints; ++i) {
    const arma::rowvec row_i = points.row(i);
    vertices[i] = Vertex::make(row_i(0), row_i(1));
  }
  cdt.insertVertices(vertices);
  cdt.eraseSuperTriangle();
  const CDT::TriangleVec triangles = cdt.triangles;
  arma::umat out(triangles.size(), 3);
  for(size_t i = 0; i < triangles.size(); ++i){
    const CDT::VerticesArr3 trgl = triangles[i].vertices;
    out(i, 0) = trgl[0];
    out(i, 1) = trgl[1];
    out(i, 2) = trgl[2];
  }
  return out;
}

arma::umat Rcpp_constrained_delaunay(
    const arma::mat & points, const arma::umat & edges
){
  Triangulation cdt(CDT::VertexInsertionOrder::AsProvided);
  size_t npoints = points.n_rows;
  std::vector<Vertex> vertices(npoints);
  for (size_t i = 0; i < npoints; ++i) {
    const arma::rowvec row_i = points.row(i);
    vertices[i] = Vertex::make(row_i(0), row_i(1));
  }
  size_t nedges = edges.n_rows;
  std::vector<Edge> Edges(nedges);
  for (size_t i = 0; i < nedges; ++i) {
    const arma::urowvec row_i = edges.row(i);
    Edge edge = Edge(row_i(0), row_i(1));
    Edges[i] = edge;
  }
  cdt.insertVertices(vertices);
  cdt.insertEdges(Edges);
  cdt.eraseOuterTrianglesAndHoles();
  const CDT::TriangleVec triangles = cdt.triangles;
  arma::umat out(triangles.size(), 3);
  for(size_t i = 0; i < triangles.size(); ++i){
    const CDT::VerticesArr3 trgl = triangles[i].vertices;
    out(i, 0) = trgl[0];
    out(i, 1) = trgl[1];
    out(i, 2) = trgl[2];
  }
  return out;
}

Answer 1

Edge does not have a default constructor, so you can’t give a vector<Edge> an initial size (since that would require each element to be initially default-constructed). Instead, make the vector empty to begin with (you can reserve() capacity for it if you like) and then add edge with push_back()… or, better yet, construct it in-place with emplace_back().