add a routine to update both the number of edges and invalid edges fo…

…r the next iteration

cpp/src/community/k_truss_impl.cuh

@@ -1115,7 +1115,34 @@ void k_truss(raft::handle_t const& handle,
 
       num_edges = edgelist_srcs.size();
 
-      //num_invalid_edges = 0; //****************** debugging purposes
+      // FIXME: Rename the variable below. Can't reuse 'invalid_edge_last'
+      // because the call below returns a type different than 'edges_to_num_triangles'
+      auto invalid_edge_last_1 =
+      thrust::stable_partition(handle.get_thrust_policy(),
+                               edges_to_num_triangles,
+                               edges_to_num_triangles + num_triangles.size(),
+                               [k] __device__(auto e) {
+                                 auto num_triangles = thrust::get<1>(e);
+                                 return num_triangles < k - 2;
+                               });
+
+      num_invalid_edges = static_cast<size_t>(
+        thrust::distance(edges_to_num_triangles, invalid_edge_last_1));
+
+
+      // copy invalid edges
+      resize_dataframe_buffer(invalid_edges_buffer, num_invalid_edges, handle.get_stream());
+
+      thrust::copy(handle.get_thrust_policy(),
+                  edges,
+                  edges + num_invalid_edges,
+                  get_dataframe_buffer_begin(invalid_edges_buffer));
+
+      // sort back the edges as those are needed later when running a binary tree
+      thrust::sort_by_key(handle.get_thrust_policy(),
+                          edges,
+                          edges + num_edges,
+                          num_triangles.begin());
     }
 
     if (num_invalid_edges == num_edges) {