Feat: combined mutation and flipping into a single procedure in

"compute_mps"

deferred_planarity_test/include/mps.h

@@ -71,7 +71,7 @@ public:
                            int mutate_point);
     
     // custom comparator function to sort nodes according to order in given vector
-    bool sortByOrder(const std::unordered_map<int, int>& node_id_to_pos, node* a, node* b); 
+    bool sortByOrder(const unordered_map<int, int>& node_id_to_pos, node* a, node* b); 
 
 	//PARENT-CHILDREN
 	void set_parent(node* n) ;
@@ -160,18 +160,26 @@ class maximal_planar_subgraph_finder
 public:
 	maximal_planar_subgraph_finder();
 	~maximal_planar_subgraph_finder();
-	int find_mps(const ogdf::Graph &G);
-	int compute_removed_edge_size(const ogdf::Graph &G, vector<int> post_order);
+
+    // functions that prepare state
+    void init_from_graph(const ogdf::Graph &G);
 	vector<int> generate_post_order(const ogdf::Graph &G);
 	vector<int> generate_mutated_post_order(const ogdf::Graph &G, vector<int> post_order, int mutate_point);
 	vector<int> generate_guided_post_order(const ogdf::Graph &G, vector<int> post_order);
-	node* get_new_node(node_type t);
-    void init_from_graph(const ogdf::Graph &G);
-	int output_removed_edge_size();
-    vector<int> return_post_order();
 	void postOrderTraversal();
 	void guidedPostOrderTraversal(vector<int> post_order);
 	void mutatedPostOrderTraversal(vector<int> post_order, int mutate_point);
+
+    // compute_mps combines functionality to reduce repeating object initialization
+    // the results are returned by modifying mutable reference
+    void compute_mps(const ogdf::Graph &G, int mutate_point, vector<int> &post_order, int &return_edge_size);
+
+	int find_mps(const ogdf::Graph &G);
+	int compute_removed_edge_size(const ogdf::Graph &G, vector<int> post_order);
+	node* get_new_node(node_type t);
+    void reset_state();
+	int output_removed_edge_size();
+    vector<int> return_post_order();
     // void set_post_order(vector<int> post_order);
     void print_post_order();
 	void sort_adj_list();

deferred_planarity_test/src/main.cpp

@@ -25,6 +25,7 @@ ogdf::Graph read_from_gml(string input_file);
 vector<int> generate_post_order(const ogdf::Graph &G);
 vector<int> generate_mutated_post_order(const ogdf::Graph &G, vector<int> post_order, int mutate_point);
 vector<int> generate_guided_post_order(const ogdf::Graph &G, vector<int> post_order);
+void compute_mps(const ogdf::Graph &G, int mutate_point, vector<int> &post_order, int &return_edge_size);
 
 void vector_printer(const vector<int>& state) {
     for (size_t i = 0; i < state.size(); ++i) {
@@ -34,53 +35,43 @@ void vector_printer(const vector<int>& state) {
 }
 
 
-vector<int> repeated_mutation(const ogdf::Graph &G, int k_max, int mutate_point) {
+vector<int> repeated_mutation(const ogdf::Graph &G, int k_max) {
     // generate first post order
     // std::cout << "generate first post order" << std::endl;
-    vector<int> state_old = generate_post_order(G);
-    vector_printer(state_old);
-    vector<int> state_new;
+    vector<int> old_order = generate_post_order(G);
+    vector_printer(old_order);
+    vector<int> temp_order = old_order;
+    int new_removed_size;
+    int old_removed_size = INT_MAX;
 
-    int old_edge_size = compute_removed_edge_size(G, state_old);
-
-    int new_edge_size = old_edge_size;
+    // prepare random selection
+    std::random_device rd;
+    std::mt19937 gen{rd()}; // seed the generator
+    int first_value = 0;
+    // we want the index of the third last value
+    // at a given traversal index, only the next iteration has the mutated value
+    int last_value = (old_order.size() - 1) - 2;
+    std::uniform_int_distribution<> dist{first_value, last_value}; // set min and max
+    int mutate_point = dist(gen); // generate number
 
     for (int k = 0; k < k_max; ++k) {
-        // mutation produces rotated view
-        // state_new = generate_mutated_post_order(G, state_old, mutate_point);
-        // simulate a mutation
-        // state_new = generate_guided_post_order(G, state_old);
-
-        // another round of guided post order gives canonical representation
-        // state_new = generate_guided_post_order(G, state_new);
-        new_edge_size = compute_removed_edge_size(G, state_old);
-
-        // if (new_edge_size < old_edge_size) {
-        //     state_old = state_new;
-        // }
-
-
+        // function compute new post_order and new_removed_size
+        // temp_order and new_removed_size will be updated with new values
+        compute_mps(G, mutate_point, temp_order, new_removed_size);
+        // if there is an improvement
+        // 1. update the removed size to use the new smaller size
+        // 2. update the old_order to be the new_order
+        if (new_removed_size < old_removed_size) {
+            old_removed_size = new_removed_size;
+            old_order = temp_order;
+        // if there is no improvement, we revert the temp_order to the old_order
+        } else {
+            temp_order = old_order;
         }
-    // vector_printer(state_new);
-    return state_old;
+    }
+    return old_order;
 }
 
-void test_correctness(const ogdf::Graph &G) {
-    vector<int> state_old = generate_post_order(G);
-    compute_removed_edge_size(G, state_old);
-}
-
-
-int get_graph_size(string input_file) {
-    ogdf::Graph G;
-
-    // utilize OGDF readGML
-    if (!ogdf::GraphIO::read(G, input_file, ogdf::GraphIO::readGML)) {
-        std::cerr << "Could not read " << input_file << ".gml" << std::endl;
-    }
-
-    return G.numberOfNodes();
-}
 
 //-----------------------------------------------------------------------------------
 // Main function.
@@ -90,20 +81,20 @@ int get_graph_size(string input_file) {
 int main(int argc, char* argv[]) {
     string input_file = argv[1];
     int k_max = std::stoi(argv[2]);
-    int mutate_point = std::stoi(argv[3]);
 
     const ogdf::Graph G = read_from_gml(input_file);
 
     // generate order here
-    vector<int> post_order = repeated_mutation(G, k_max, mutate_point);
+    vector<int> post_order = repeated_mutation(G, k_max);
 
     // test timing of function
     // test_correctness(G);   
 
     // // print final order and number of edges
-    // // print post_order
-    // std::copy(post_order.begin(), post_order.end(), std::ostream_iterator<int>(std::cout, ","));
-    // std::cout << std::endl;
+    std::cout << "---" << std::endl;
+    std::cout << "final report" << std::endl;
+    std::copy(post_order.begin(), post_order.end(), std::ostream_iterator<int>(std::cout, ","));
+    std::cout << std::endl;
     int removed_edges = compute_removed_edge_size(G, post_order);
     std::cout << "Number of removed edges: " << removed_edges << std::endl;
 

deferred_planarity_test/src/mps.cpp

@@ -99,7 +99,8 @@ maximal_planar_subgraph_finder::mutatedPostOrderTraversal(vector<int> post_order
 	node::init_mark();
 
     vector<int> rev_post_order;
-    for (size_t i = post_order.size() - 1; i >= 0; --i) {
+
+    for (size_t i = post_order.size() - 1; i != std::numeric_limits<size_t>::max(); --i) {
         rev_post_order.push_back(post_order[i]);
     }
 	int postOrderID = 0;

deferred_planarity_test/src/mps_test.cpp

@@ -8,6 +8,7 @@
 #include <ogdf/fileformats/GraphIO.h>
 
 // #define DEBUG
+#define DEBUG_2
 // #define TIME
 
 //-----------------------------------------------------------------------------------
@@ -54,6 +55,12 @@ vector<int> generate_guided_post_order(const ogdf::Graph &G, vector<int> post_or
 }
 
 
+void compute_mps(const ogdf::Graph &G, int mutate_point, vector<int> &post_order, int &return_edge_size) {
+    maximal_planar_subgraph_finder m;
+    m.compute_mps(G, mutate_point, post_order, return_edge_size);
+}
+
+
 // ---------
 
 int maximal_planar_subgraph_finder::find_mps(const ogdf::Graph &G) {
@@ -85,6 +92,7 @@ vector<int> maximal_planar_subgraph_finder::generate_post_order(const ogdf::Grap
 // result of this will be used as input to "compute_removed_edge_size"
 vector<int> maximal_planar_subgraph_finder::generate_mutated_post_order(const ogdf::Graph &G, vector<int> post_order, int mutate_point) {
 	init_from_graph(G);
+
     mutatedPostOrderTraversal(post_order, mutate_point);
 
     #ifdef DEBUG
@@ -164,6 +172,36 @@ int maximal_planar_subgraph_finder::compute_removed_edge_size(const ogdf::Graph
 	return output_removed_edge_size();
 }
 
+void maximal_planar_subgraph_finder::reset_state() {
+    _post_order_list.clear();
+}
+
+void maximal_planar_subgraph_finder::compute_mps(const ogdf::Graph &G, int mutate_point, vector<int> &post_order, int &return_edge_size) {
+    init_from_graph(G);
+    mutatedPostOrderTraversal(post_order, mutate_point);
+	sort_adj_list();
+	determine_edges();
+    back_edge_traversal();
+    return_edge_size = output_removed_edge_size();
+
+    // now we get the canonical representation of the post order
+    vector<int> temp_post_order = return_post_order(); 
+    #ifdef DEBUG_2
+    std::cout << "post_order pre-flip" << std::endl;
+    print_post_order();
+    #endif
+
+    reset_state(); // clear the _post_order_list
+    // perform guided Post Order Traversal to flip the tree
+    guidedPostOrderTraversal(temp_post_order);
+    #ifdef DEBUG_2
+    std::cout << "post order post_flip" << std::endl;
+    print_post_order();
+    #endif
+
+    post_order = return_post_order();
+}
+
 //-----------------------------------------------------------------------------------
 // Input, output
 //-----------------------------------------------------------------------------------

deferred_planarity_test/src/node.cpp

@@ -119,7 +119,6 @@ void node::guided_DFS_visit(vector<node *> &dfsList,
 
     #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() << ")" << ",";
     }
@@ -171,6 +170,13 @@ void node::mutated_DFS_visit(vector<node*> &dfsList,
         }
     }
 
+    #ifdef DEBUG_MUTATION
+    std::cout << "current node:" << this->node_id() << std::endl;
+    for (size_t i = 0; i < neighbor_list.size(); ++i) {
+        std::cout << neighbor_list[i]->node_id() << "(" << neighbor_list[i]->is_marked() << ")" << ",";
+    }
+    std::cout << std::endl;
+    #endif
 
 
     // since we increment the index before this line, the current index is "index - 1"
@@ -183,13 +189,6 @@ void node::mutated_DFS_visit(vector<node*> &dfsList,
         // Use std::shuffle to shuffle the elements in the vector
         std::shuffle(neighbor_list.begin(), neighbor_list.end(), rng);
 
-        #ifdef DEBUG_MUTATION
-        std::cout << "current node:" << this->node_id() << std::endl;
-        for (size_t i = 0; i < neighbor_list.size(); ++i) {
-            std::cout << neighbor_list[i]->node_id() << "(" << neighbor_list[i]->is_marked() << ")" << ",";
-        }
-        std::cout << std::endl;
-        #endif
     } 
 
     // increment traversal index after checking