max matching seems to work

include/rxmesh/matrix/nd_permute.cuh

@@ -26,7 +26,7 @@ struct Graph
  // vertex should not contain the vertex itself.
  std::vector<T> adjncy;
 
- void print()
+ void print() const
  {
  std::cout << "\n*** graph ***\n";
  for (int i = 0; i < n; ++i) {
@@ -117,8 +117,8 @@ void construct_a_simple_chordal_graph(Graph<T>& graph)
  * @brief construct patch neighbor graph which is the same as what we store in
  * PatchStash but in format acceptable by metis
  */
-void construct_patches_neighbor_graph(RXMeshStatic& rx,
- Graph<idx_t>& patches_graph)
+template <typename T>
+void construct_patches_neighbor_graph(RXMeshStatic& rx, Graph<T>& patches_graph)
 {
  uint32_t num_patches = rx.get_num_patches();
 
@@ -281,6 +281,9 @@ void random_max_matching(const Graph<integer_t>& graph,
  if (graph.n <= 1) {
  return;
  }
+
+ // graph.print();
+
  std::vector<bool> matched(graph.n, false);
 
  Level<integer_t> l;
@@ -293,24 +296,27 @@ void random_max_matching(const Graph<integer_t>& graph,
 
  // TODO traverse the graph in a random order
  for (int v = 0; v < graph.n; ++v) {
- // the neighbor with which we will match v
- integer_t matched_neighbour = integer_t(-1);
-
- for (int i = graph.xadj[v]; i < graph.xadj[v + 1]; ++i) {
- integer_t n = graph.adjncy[i];
- if (!matched[n]) {
- matched_neighbour = n;
- break;
- }
- }
- if (matched_neighbour != integer_t(-1)) {
- int pa = l.nodes.size();
+ if (!matched[v]) {
+
+ // the neighbor with which we will match v
+ integer_t matched_neighbour = integer_t(-1);
 
- l.nodes.push_back(Node(pa, v, matched_neighbour));
- matched[v] = true;
- matched[matched_neighbour] = true;
- parents[v] = pa;
- parents[matched_neighbour] = pa;
+ for (int i = graph.xadj[v]; i < graph.xadj[v + 1]; ++i) {
+ integer_t n = graph.adjncy[i];
+ if (!matched[n]) {
+ matched_neighbour = n;
+ break;
+ }
+ }
+ if (matched_neighbour != integer_t(-1)) {
+ int pa = l.nodes.size();
+
+ l.nodes.push_back(Node(pa, v, matched_neighbour));
+ matched[v] = true;
+ matched[matched_neighbour] = true;
+ parents[v] = pa;
+ parents[matched_neighbour] = pa;
+ }
  }
  }
 
@@ -337,24 +343,27 @@ void random_max_matching(const Graph<integer_t>& graph,
  for (int i = 0; i < l.nodes.size(); ++i) {
  const auto& node = l.nodes[i];
  // the neighbors to this node is the union of neighbors of node.lch and
- // node.rch
+ // node.rch. We don't store node.lcu/node.rch, but instead we store
+ // their parent (because this is the coarse graph)
  std::unordered_set<integer_t> u_neighbour;
 
  auto get_neighbour = [&](integer_t x, integer_t y) {
  for (integer_t n = graph.xadj[x]; n < graph.xadj[x + 1]; ++n) {
  if (graph.adjncy[n] != y) {
- u_neighbour.insert(graph.adjncy[n]);
+ assert(parents[graph.adjncy[n]] != integer_t(-1));
+ u_neighbour.insert(parents[graph.adjncy[n]]);
  }
  }
  };
 
  get_neighbour(node.lch, node.rch);
  get_neighbour(node.rch, node.lch);
 
+ c_graph.xadj[i + 1] = c_graph.xadj[i];
  for (const auto& u : u_neighbour) {
  // actually what we insert in the coarse graph is the parents
- c_graph.adjncy.push_back(parents[u]);
- c_graph.xadj[i + 1] = c_graph.xadj[i] + 1;
+ c_graph.adjncy.push_back(u);
+ c_graph.xadj[i + 1]++;
  }
  }
 
@@ -372,8 +381,14 @@ void nd_permute(RXMeshStatic& rx, std::vector<int>& h_permute)
  // a graph representing the patch connectivity
  Graph<int> p_graph;
 
- // construct_patches_neighbor_graph(rx, p_graph);
- construct_a_simple_chordal_graph(p_graph);
+ construct_patches_neighbor_graph(rx, p_graph);
+ // construct_a_simple_chordal_graph(p_graph);
+
+ rx.render_vertex_patch();
+ rx.render_edge_patch();
+ rx.render_face_patch();
+
+ polyscope::show();
 
  // create max match tree
  random_max_matching(p_graph, max_match_tree);