94 lines
2.6 KiB
C++
94 lines
2.6 KiB
C++
//-----------------------------------------------------------------------------------
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// A simple code that test the MPS algorighm.
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//-----------------------------------------------------------------------------------
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#include "mps.h"
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#include <iostream>
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#include <cstdlib>
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#include <climits>
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#include <string>
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#include <algorithm>
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#include <iterator>
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#include <random>
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#include <vector>
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#include <ogdf/fileformats/GraphIO.h>
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using namespace std;
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int compute_removed_edge_size(string input_file, vector<int> post_order);
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vector<int> generate_post_order(string input_file);
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vector<int> generate_mutated_post_order(string input_file, vector<int> post_order);
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double temp_decay(int k, int k_max) {
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return 1.0 - ((k + 1.0) / (k_max));
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}
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vector<int> sa_solve(string input_file, int k_max) {
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// create sampling function
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std::random_device rd;
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std::mt19937 rng(rd());
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std::uniform_real_distribution<> distribution(0.0, 1.0);
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// generate first state
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vector<int> state_old = generate_post_order(input_file);
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vector<int> state_new;
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int e_old = compute_removed_edge_size(input_file, state_old);
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int e_new = 0;
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int delta = 0;
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// initialize terms
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double temp = 100;
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for (int k = 0; k < k_max; ++k) {
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temp = temp_decay(k, k_max);
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state_new = generate_mutated_post_order(input_file, state_old);
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e_new = compute_removed_edge_size(input_file, state_new);
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delta = e_new - e_old;
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if (std::exp( -(delta) / temp) > distribution(rng)) {
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state_old = state_new;
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e_old = e_new;
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}
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// std::cout << "temp: " << temp << ", score: " << e_old << std::endl;
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}
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return state_old;
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}
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int get_graph_size(string input_file) {
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ogdf::Graph G;
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// utilize OGDF readGML
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if (!ogdf::GraphIO::read(G, input_file, ogdf::GraphIO::readGML)) {
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std::cerr << "Could not read " << input_file << ".gml" << std::endl;
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}
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return G.numberOfNodes();
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}
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//-----------------------------------------------------------------------------------
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// Main function.
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//-----------------------------------------------------------------------------------
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int main(int argc, char* argv[]) {
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string input_file = argv[1];
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int k_max = std::stoi(argv[2]);
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// generate order here
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vector<int> post_order = sa_solve(input_file, k_max);
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// std::copy(post_order.begin(), post_order.end(), std::ostream_iterator<int>(std::cout, " "));
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// std::cout << std::endl;
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// print order
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int removed_edges = compute_removed_edge_size(input_file, post_order);
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std::cout << "Number of removed edges: " << removed_edges << std::endl;
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return 0;
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}
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