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Fix: mutate starting node also 

Perf: use reserve for containers, use const reference
This commit is contained in:
Richard Wong 2024-03-04 16:44:05 +09:00
parent 476c221cc2
commit c58f2de199
Signed by: richard
GPG Key ID: 5BD36BA2E9EE33D0
5 changed files with 97 additions and 59 deletions
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17
deferred_planarity_test/include/mps.h
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@ -63,12 +63,13 @@ public:
const vector<node *> &node_list,
int &return_index,
const unordered_map<int, int> &node_id_to_pos);
void mutated_DFS_visit(vector<node*> &dfsList,
vector<node*> &node_list,
void mutated_DFS_visit(vector<node *> &dfsList,
vector<node *> &node_list,
int &index,
int &traversal_index,
vector<int> rev_post_order,
int mutate_point);
const unordered_map<int, int> &node_id_to_pos,
int mutate_point,
mt19937 rng);
// custom comparator function to sort nodes according to order in given vector
bool sortByOrder(const unordered_map<int, int>& node_id_to_pos, node* a, node* b);
@ -164,11 +165,11 @@ public:
// 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);
vector<int> generate_mutated_post_order(const ogdf::Graph &G, const vector<int> &post_order, int mutate_point);
vector<int> generate_guided_post_order(const ogdf::Graph &G, const vector<int> &post_order);
void postOrderTraversal();
void guidedPostOrderTraversal(vector<int> post_order);
void mutatedPostOrderTraversal(vector<int> post_order, int mutate_point);
void guidedPostOrderTraversal(const vector<int> &post_order);
void mutatedPostOrderTraversal(const vector<int> &post_order, int mutate_point);
// compute_mps combines functionality to reduce repeating object initialization
// the results are returned by modifying mutable reference

3
deferred_planarity_test/src/main.cpp
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@ -52,12 +52,11 @@ vector<int> repeated_mutation(const ogdf::Graph &G, int k_max) {
// 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) {
// 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);
compute_mps(G, dist(gen), 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

51
deferred_planarity_test/src/mps.cpp
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@ -24,6 +24,8 @@ maximal_planar_subgraph_finder::get_new_node(node_type t) {
vector<int>
maximal_planar_subgraph_finder::return_post_order() {
vector<int> post_order;
// we have arg number of elements
post_order.reserve(_post_order_list.size()); // reserve for decreased reallocation
for (size_t i = 0; i < _post_order_list.size(); ++i) {
post_order.push_back(_post_order_list[i]->node_id());
}
@ -48,7 +50,7 @@ maximal_planar_subgraph_finder::postOrderTraversal() {
// take in a post-order argument then traces the graph in the same order
// return is by reference via _post_order_list
void
maximal_planar_subgraph_finder::guidedPostOrderTraversal(vector<int> post_order) {
maximal_planar_subgraph_finder::guidedPostOrderTraversal(const vector<int> &post_order) {
node::init_mark();
// // implementation 1: pass reversed vector
@ -61,6 +63,7 @@ maximal_planar_subgraph_finder::guidedPostOrderTraversal(vector<int> post_order)
// implementation 2: use unordered_map to map node_id to position in reversed post_order
unordered_map<int, int> node_id_to_pos;
node_id_to_pos.reserve(post_order.size());
int j = 0;
// we flip the post_order vector around
for (size_t i = post_order.size() - 1; i != std::numeric_limits<size_t>::max(); --i) {
@ -73,6 +76,10 @@ maximal_planar_subgraph_finder::guidedPostOrderTraversal(vector<int> post_order)
int start = post_order[post_order.size() - 1];
int i = start;
// reserve for _post_order_list to decrease reallocation
_post_order_list.reserve(_node_list.size());
while (true)
{
if (((start > 0) && (i == (start - 1))) || ((start == 0 ) && (i == end_condition - 1)))
@ -95,24 +102,50 @@ maximal_planar_subgraph_finder::guidedPostOrderTraversal(vector<int> post_order)
// take in a post-order argument then traces the graph in the same order
// return is by reference via _post_order_list
void
maximal_planar_subgraph_finder::mutatedPostOrderTraversal(vector<int> post_order, int mutate_point) {
maximal_planar_subgraph_finder::mutatedPostOrderTraversal(const vector<int> &post_order, int mutate_point) {
node::init_mark();
vector<int> rev_post_order;
// // implementation 1: use vector
// vector<int> rev_post_order;
// for (size_t i = post_order.size() - 1; i != std::numeric_limits<size_t>::max(); --i) {
// rev_post_order.push_back(post_order[i]);
// }
// implementation 2: use unordered_map to map node_id to position in reversed post_order
unordered_map<int, int> node_id_to_pos;
node_id_to_pos.reserve(post_order.size());
int j = 0;
// we flip the post_order vector around
for (size_t i = post_order.size() - 1; i != std::numeric_limits<size_t>::max(); --i) {
rev_post_order.push_back(post_order[i]);
node_id_to_pos[post_order[i]] = j++;
}
int postOrderID = 0;
int traversal_index = 0;
// Define the range [0, n]
// int n = _node_list.size() - 1; // Change 'n' to your desired upper bound
// setup random rng function
std::random_device rd;
std::mt19937 rng{rd()};
int start = 0;
// if we mutate first node, we will select a random starting node
if (mutate_point == 0) {
int first_value = 0;
int last_value = post_order.size() - 1;
std::uniform_int_distribution<> dist{first_value, last_value};
start = post_order[dist(rng)];
// if we don't mutate first, we just use the root node of the post_order
} else {
start = post_order[post_order.size() - 1];
}
// set loop variables
int start = rev_post_order[0];
int i = start;
// reserve for _post_order_list to decrease reallocation
_post_order_list.reserve(_node_list.size());
int end_condition = _node_list.size();
// this loop assumes start is not from 0
@ -123,13 +156,13 @@ 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, traversal_index, rev_post_order, mutate_point);
_node_list[i]->mutated_DFS_visit(_post_order_list, _node_list, postOrderID, traversal_index, node_id_to_pos, mutate_point, rng);
}
break;
}
if (!_node_list[i]->is_marked())
{
_node_list[i]->mutated_DFS_visit(_post_order_list, _node_list, postOrderID, traversal_index, rev_post_order, mutate_point);
_node_list[i]->mutated_DFS_visit(_post_order_list, _node_list, postOrderID, traversal_index, node_id_to_pos, mutate_point, rng);
}
i = (i + 1) % end_condition;
}

7
deferred_planarity_test/src/mps_test.cpp
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@ -8,7 +8,7 @@
#include <ogdf/fileformats/GraphIO.h>
// #define DEBUG
#define DEBUG_2
// #define DEBUG_2
// #define TIME
//-----------------------------------------------------------------------------------
@ -90,7 +90,7 @@ 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) {
vector<int> maximal_planar_subgraph_finder::generate_mutated_post_order(const ogdf::Graph &G, const vector<int> &post_order, int mutate_point) {
init_from_graph(G);
mutatedPostOrderTraversal(post_order, mutate_point);
@ -104,7 +104,7 @@ vector<int> maximal_planar_subgraph_finder::generate_mutated_post_order(const og
}
// result of this will be used as input to "compute_removed_edge_size"
vector<int> maximal_planar_subgraph_finder::generate_guided_post_order(const ogdf::Graph &G, vector<int> post_order) {
vector<int> maximal_planar_subgraph_finder::generate_guided_post_order(const ogdf::Graph &G, const vector<int> &post_order) {
init_from_graph(G);
guidedPostOrderTraversal(post_order);
@ -208,6 +208,7 @@ void maximal_planar_subgraph_finder::compute_mps(const ogdf::Graph &G, int mutat
void maximal_planar_subgraph_finder::init_from_graph(const ogdf::Graph &G) {
// create nodes
_node_list.reserve(G.numberOfNodes());
for (int i = 0; i < G.numberOfNodes(); ++i) {
_node_list.push_back(new node(P_NODE));
_node_list[i]->set_id(i);

66
deferred_planarity_test/src/node.cpp
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@ -139,13 +139,13 @@ void node::guided_DFS_visit(vector<node *> &dfsList,
++return_index;
}
void node::mutated_DFS_visit(vector<node*> &dfsList,
vector<node*> &node_list,
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)
const unordered_map<int, int> &node_id_to_pos,
int mutate_point,
mt19937 rng)
{
// mark current node
@ -154,22 +154,37 @@ void node::mutated_DFS_visit(vector<node*> &dfsList,
// 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
// create an unordered set to efficiently check for presence of an element
std::unordered_set<int> neighbor_set;
for (size_t i = 0; i < _adj_list.size(); ++i) {
neighbor_set.insert(_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 (size_t 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]]);
}
// // implementation 1: naively check by running through all elements of rev_post_order
// // create an unordered set to efficiently check for presence of an element
// std::unordered_set<int> neighbor_set;
// for (size_t i = 0; i < _adj_list.size(); ++i) {
// neighbor_set.insert(_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 (size_t 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]]);
// }
// }
vector<node*> neighbor_list = _adj_list;
// if the current index matches the mutate_point, then we know this is the cycle to mutate
if (traversal_index == mutate_point) {
// we shuffle the neighbor list
std::shuffle(neighbor_list.begin(), neighbor_list.end(), rng);
// otherwise just sort based on the order set by node_id_to_pos, which is
// set by the reversed post_order
} else {
std::sort(neighbor_list.begin(), neighbor_list.end(), [this, &node_id_to_pos](node *a, node *b)
{ return sortByOrder(node_id_to_pos, a, b); });
}
#ifdef DEBUG_MUTATION
std::cout << "current node:" << this->node_id() << std::endl;
for (size_t i = 0; i < neighbor_list.size(); ++i) {
@ -179,17 +194,6 @@ void node::mutated_DFS_visit(vector<node*> &dfsList,
#endif
// 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 (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;
std::mt19937 rng(rd());
// Use std::shuffle to shuffle the elements in the vector
std::shuffle(neighbor_list.begin(), neighbor_list.end(), rng);
}
// increment traversal index after checking
// next node will receive incremented index
@ -200,7 +204,7 @@ void node::mutated_DFS_visit(vector<node*> &dfsList,
if (!neighbor_list[i]->is_marked())
{
neighbor_list[i]->_parent = this;
neighbor_list[i]->mutated_DFS_visit(dfsList, node_list, return_index, traversal_index, rev_post_order, mutate_point);
neighbor_list[i]->mutated_DFS_visit(dfsList, node_list, return_index, traversal_index, node_id_to_pos, mutate_point, rng);
}
}