Bug: fixed broken guided traversal. Discovered that guided traversal

rotates the dfs tree.

deferred_planarity_test/include/mps.h

@@ -56,8 +56,17 @@ public:
 	node* adj(int i);
 	void set_adj_list(vector<node*> vec);
 	void DFS_visit(vector<node*> &dfsList, int &index);
-	void guided_DFS_visit(vector<node*> &dfsList, vector<node*> &node_list, int &index, vector<int> rev_post_order);
+    void guided_DFS_visit(vector<node *> &dfsList,
-	void mutated_DFS_visit(vector<node*> &dfsList, vector<node*> &node_list, int &index, vector<int> rev_post_order, int &mutate_point);
+                          vector<node *> &node_list,
+                          int &return_index,
+                          vector<int> rev_post_order,
+                          int prev_node);
+    void mutated_DFS_visit(vector<node*> &dfsList, 
+                           vector<node*> &node_list, 
+                           int &index, 
+                           int &traversal_index, 
+                           vector<int> rev_post_order, 
+                           int mutate_point);
 
 	//PARENT-CHILDREN
 	void set_parent(node* n) ;
@@ -150,6 +159,7 @@ public:
 	int compute_removed_edge_size(string input_file, vector<int> post_order);
 	vector<int> generate_post_order(string input_file);
 	vector<int> generate_mutated_post_order(string input_file, vector<int> post_order);
+	vector<int> generate_guided_post_order(string input_file, vector<int> post_order);
 	node* get_new_node(node_type t);
     void read_from_gml(string input_file);
 	int output_removed_edge_size();

deferred_planarity_test/src/main.cpp

@@ -21,15 +21,31 @@ int compute_removed_edge_size(string input_file, vector<int> post_order);
 
 vector<int> generate_post_order(string input_file);
 vector<int> generate_mutated_post_order(string input_file, vector<int> post_order);
+vector<int> generate_guided_post_order(string input_file, vector<int> post_order);
 
 
 vector<int> repeated_mutation(string input_file, int k_max) {
+    // generate first post order
+    std::cout << "generate first post order" << std::endl;
     vector<int> state_old = generate_post_order(input_file);
     vector<int> state_new;
     int num_removed_edges;
     for (int k = 0; k < k_max; ++k) {
-        state_new = generate_mutated_post_order(input_file, state_old);
+        // rotate it first
-        num_removed_edges = compute_removed_edge_size(input_file, state_new);
+        std::cout << "cycle:" << k << std::endl;
+        std::cout << "rotate the dfs tree" << std::endl;
+        state_new = generate_guided_post_order(input_file, state_old);
+        // then the next traversal will rotate it back
+        std::cout << "mutate the dfs tree" << std::endl;
+        state_new = generate_mutated_post_order(input_file, state_new);
+        // num_removed_edges = compute_removed_edge_size(input_file, state_new);
+        // first time will rotate the tree
+        std::cout << "rotate the dfs tree" << std::endl;
+        state_new = generate_guided_post_order(input_file, state_new);
+        // second time will rotate back the rotated tree
+        std::cout << "print the mutated tree again" << std::endl;
+        state_new = generate_guided_post_order(input_file, state_new);
+        std::cout << std::endl;
     }
     return state_new;
 }
@@ -62,8 +78,8 @@ int main(int argc, char* argv[]) {
     int k_max = std::stoi(argv[2]);
 
     // generate order here
-    // vector<int> post_order = repeated_mutation(input_file, k_max);
+    vector<int> post_order = repeated_mutation(input_file, k_max);
-    test_correctness(input_file);
+    // test_correctness(input_file);
 
     // // print final order and number of edges
     // // print post_order

deferred_planarity_test/src/mps.cpp

@@ -61,19 +61,21 @@ maximal_planar_subgraph_finder::guidedPostOrderTraversal(vector<int> post_order)
     int end_condition = _node_list.size();
     int start = rev_post_order[0];
     int i = start;
+    
+    int prev_node = INT_MAX;
     while (true)
     {
         if (((start > 0) && (i == (start - 1))) || ((start == 0 ) && (i == end_condition - 1)))
         {
             if (!_node_list[i]->is_marked())
             {
-                _node_list[i]->guided_DFS_visit(_post_order_list, _node_list, postOrderID, rev_post_order);
+                _node_list[i]->guided_DFS_visit(_post_order_list, _node_list, postOrderID, rev_post_order, prev_node);
             }
             break;
         }
         if (!_node_list[i]->is_marked())
         {
-            _node_list[i]->guided_DFS_visit(_post_order_list, _node_list, postOrderID, rev_post_order);
+            _node_list[i]->guided_DFS_visit(_post_order_list, _node_list, postOrderID, rev_post_order, prev_node);
         }
         i = (i + 1) % end_condition;
     }
@@ -91,6 +93,7 @@ maximal_planar_subgraph_finder::mutatedPostOrderTraversal(vector<int> post_order
         rev_post_order.push_back(post_order[i]);
     }
 	int postOrderID = 0;
+    int traversal_index = 0;
 
     // introduce random selection
     std::random_device rd;
@@ -123,13 +126,13 @@ maximal_planar_subgraph_finder::mutatedPostOrderTraversal(vector<int> post_order
         {
             if (!_node_list[i]->is_marked())
             {
-                _node_list[i]->mutated_DFS_visit(_post_order_list, _node_list, postOrderID, rev_post_order, mutate_point);
+                _node_list[i]->mutated_DFS_visit(_post_order_list, _node_list, postOrderID, traversal_index, rev_post_order, mutate_point);
             }
             break;
         }
         if (!_node_list[i]->is_marked())
         {
-            _node_list[i]->mutated_DFS_visit(_post_order_list, _node_list, postOrderID, rev_post_order, mutate_point);
+            _node_list[i]->mutated_DFS_visit(_post_order_list, _node_list, postOrderID, traversal_index, rev_post_order, mutate_point);
         }
         i = (i + 1) % end_condition;
     }

deferred_planarity_test/src/mps_test.cpp

@@ -33,6 +33,11 @@ vector<int> generate_mutated_post_order(string input_file, vector<int> post_orde
     return m.generate_mutated_post_order(input_file, post_order);
 }
 
+vector<int> generate_guided_post_order(string input_file, vector<int> post_order) {
+    maximal_planar_subgraph_finder m;
+    return m.generate_guided_post_order(input_file, post_order);
+}
+
 
 // ---------
 
@@ -55,6 +60,7 @@ vector<int> maximal_planar_subgraph_finder::generate_post_order(string input_fil
     postOrderTraversal();
 
     #ifdef DEBUG
+    std::cout << "standard post order traversal" << std::endl;
     print_post_order();
     #endif
 
@@ -67,6 +73,20 @@ vector<int> maximal_planar_subgraph_finder::generate_mutated_post_order(string i
     mutatedPostOrderTraversal(post_order);
 
     #ifdef DEBUG
+    std::cout << "mutated post order traversal" << std::endl;
+    print_post_order();
+    #endif
+
+    return return_post_order();
+}
+
+// result of this will be used as input to "compute_removed_edge_size"
+vector<int> maximal_planar_subgraph_finder::generate_guided_post_order(string input_file, vector<int> post_order) {
+    read_from_gml(input_file);
+    guidedPostOrderTraversal(post_order);
+
+    #ifdef DEBUG
+    std::cout << "guided post order traversal" << std::endl;
     print_post_order();
     #endif
 
@@ -74,16 +94,13 @@ vector<int> maximal_planar_subgraph_finder::generate_mutated_post_order(string i
 }
 
 
+
 int maximal_planar_subgraph_finder::compute_removed_edge_size(string input_file, vector<int> post_order) {
 	read_from_gml(input_file);
     guidedPostOrderTraversal(post_order);
     
-    // set post_order_index
-    for (int i = 0; i < _post_order_list.size(); ++i) {
-        _node_list[_post_order_list[i]->node_id()]->set_post_order_index(i);
-    }
-    
     #ifdef DEBUG
+    std::cout << "guided post order traversal" << std::endl;
     print_post_order();
     #endif
 

deferred_planarity_test/src/node.cpp

@@ -69,50 +69,96 @@ void node::DFS_visit(vector<node*> &dfsList, int &index) {
 }
 
 
-void node::guided_DFS_visit(vector<node*> &dfsList, vector<node*> &node_list, int &index, vector<int> rev_post_order) {
+void node::guided_DFS_visit(vector<node *> &dfsList, 
+                            vector<node *> &node_list, 
+                            int &return_index, 
+                            vector<int> rev_post_order,
+                            int prev_node)
+{
+
 	mark();
 
+    // purpose of this block: create list of neighbors ordered in the order they appear in rev_post_order
+    // we want to select neighbors that match the rev_post_order at the specific traversal_index
 
-    // purpose of this block: create list of neighbors
+    // create an unordered set to efficiently check for presence of an element
-    vector<node *> neighbor_list;
+    std::unordered_set<int> neighbor_set; 
     for (int i = 0; i < _adj_list.size(); ++i) {
-        // we get the neighbors via _adj_list
+        neighbor_set.insert(_adj_list[i]->node_id());
-        // we get the id's of the neighbor nodes, then we use the id's to get the actual nodes via node_list
-        // node_list maps id to the actual node
-        neighbor_list.push_back(node_list[_adj_list[i]->node_id()]);
     }
+    // when an element in rev_post_order is found in neighbor_set, we add that to neighbor_list
+    // this produces a neighbor_list that follows the order by which they occur in the rev_post_order
+    // it is ok if the neighbor was already visited before, 
+    // it would've been marked and will be subsequently ignored
+    vector<node *> neighbor_list;
+    for (int i = 0; i < rev_post_order.size(); ++i) {
+        if (neighbor_set.find(rev_post_order[i]) != neighbor_set.end()) {
+            // only add if newly encountered
+            if (!node_list[rev_post_order[i]]->is_marked()) {
+                neighbor_list.push_back(node_list[rev_post_order[i]]);
+            }
+        }
+    }
+
+    #ifdef DEBUG
+    std::cout << "current node:" << this->node_id() << std::endl;
+    std::cout << "prev node:" << prev_node << std::endl;
+    for (int i = 0; i < neighbor_list.size(); ++i) {
+        std::cout << neighbor_list[i]->node_id() << "(" << neighbor_list[i]->is_marked() << ")" << ",";
+    }
+    std::cout << std::endl;
+    #endif
+
 
 	
 	for (int i = 0; i < neighbor_list.size(); ++i) {
 		if (!neighbor_list[i]->is_marked()) {
 			neighbor_list[i]->_parent = this;
-			neighbor_list[i]->guided_DFS_visit(dfsList, node_list, index, rev_post_order);
+			neighbor_list[i]->guided_DFS_visit(dfsList, node_list, return_index, rev_post_order, this->node_id());
 		}
 	}
 
-    set_post_order_index(index);
+    set_post_order_index(return_index);
 	dfsList.push_back(this);
-	++index;
+	++return_index;
 }
 
 
-void node::mutated_DFS_visit(vector<node*> &dfsList, vector<node*> &node_list, int &index, vector<int> rev_post_order, int &mutate_point) {
+void node::mutated_DFS_visit(vector<node*> &dfsList, 
+                             vector<node*> &node_list, 
+                             int &return_index, 
+                             int &traversal_index, 
+                             vector<int> rev_post_order, 
+                             int mutate_point)
+{
+
     // mark current node
 	mark();
     
-    // purpose of this block: create list of neighbors
+    // purpose of this block: create list of neighbors ordered in the order they appear in rev_post_order
-    vector<node *> neighbor_list;
+    // we want to select neighbors that match the rev_post_order at the specific traversal_index
+
+    // create an unordered set to efficiently check for presence of an element
+    std::unordered_set<int> neighbor_set; 
     for (int i = 0; i < _adj_list.size(); ++i) {
-        // we get the neighbors via _adj_list
+        neighbor_set.insert(_adj_list[i]->node_id());
-        // we get the id's of the neighbor nodes, then we use the id's to get the actual nodes via node_list
-        // node_list maps id to the actual node
-        neighbor_list.push_back(node_list[_adj_list[i]->node_id()]);
     }
+    // when an element in rev_post_order is found in neighbor_set, we add that to neighbor_list
+    // this produces a neighbor_list that follows the order by which they occur in the rev_post_order
+    // it is ok if the neighbor was already visited before, 
+    // it would've been marked and will be subsequently ignored
+    vector<node *> neighbor_list;
+    for (int i = 0; i < rev_post_order.size(); ++i) {
+        if (neighbor_set.find(rev_post_order[i]) != neighbor_set.end()) {
+            neighbor_list.push_back(node_list[rev_post_order[i]]);
+        }
+    }
+
     
 
     // since we increment the index before this line, the current index is "index - 1"
     // if the current index matches the mutate_point, then we know this is the cycle to mutate
-    if (index - 1 == mutate_point) {
+    if (traversal_index == mutate_point) {
         // Create a random number generator and seed it
         // std::cout << "mutated at index: " << index - 1<< "and at mutate point: " << mutate_point << std::endl;
         std::random_device rd;
@@ -121,22 +167,24 @@ void node::mutated_DFS_visit(vector<node*> &dfsList, vector<node*> &node_list, i
         std::shuffle(neighbor_list.begin(), neighbor_list.end(), rng);
     } 
 
+    // increment traversal index after checking
+    // next node will receive incremented index
+    traversal_index++;
+    
     for (int i = 0; i < neighbor_list.size(); ++i)
     {
         if (!neighbor_list[i]->is_marked())
         {
             neighbor_list[i]->_parent = this;
-            neighbor_list[i]->mutated_DFS_visit(dfsList, node_list, index, rev_post_order, mutate_point);
+            neighbor_list[i]->mutated_DFS_visit(dfsList, node_list, return_index, traversal_index, rev_post_order, mutate_point);
         }
     }
 
-	set_post_order_index(index);
+	set_post_order_index(return_index);
 	dfsList.push_back(this);
-	++index;
+	++return_index;
 }
 
-
-
 //-----------------------------------------------------------------------------------
 // PARENT-CHILDREN
 //-----------------------------------------------------------------------------------