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FullWorldDijkstra.hpp
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FullWorldDijkstra.hpp
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#pragma once
#include <WGraph.hpp>
#include <set>
#include <vector>
#include <string>
#include <iostream>
#include <Dijkstra.hpp>
class FullWorldDijkstra {
public:
using WGraph = graph_tools::WGraph;
FullWorldDijkstra(const WGraph &wg, int root, int goal) :
_wg(wg),
_root(root),
_goal(goal),
_traversed_edges(0),
_fp_compares(0),
_fp_adds(0) {}
std::pair<std::vector<int>, std::vector<float>>
run() {
_distance.clear();
_path.clear();
_teps_to_find.clear();
_distance.resize(_wg.num_nodes(), INFINITY);
_path.resize(_wg.num_nodes(),-1);
_teps_to_find.resize(_wg.num_nodes(),-1);
_distance[_root] = 0.0;
_path[_root] = _root;
_teps_to_find[_root] = 0;
std::set<int> unvisited;
for (int v = 0; v < _wg.num_nodes(); v++)
unvisited.insert(v);
while (!unvisited.empty()) {
// approx. deletion with O(logN)
int minsrc = -1;
float mindst = INFINITY;
for (int src : unvisited) {
if (_distance[src] < mindst) {
minsrc = src;
mindst = _distance[src];
}
_fp_compares += 1;
}
int src = minsrc;
if (src == _goal)
break;
auto wneib = _wg.wneighbors(src);
for (auto &pair : wneib) {
int dst = pair.first;
float w = pair.second;
if (_distance[src]+w < _distance[dst]) {
_path[dst] = src;
_distance[dst] = _distance[src]+w;
}
if (_teps_to_find[dst] == -1) {
_teps_to_find[dst] = _traversed_edges;
}
_fp_adds += 1;
_fp_compares += 1;
_traversed_edges += 1;
}
unvisited.erase(src);
}
return {_path, _distance};
}
int goal() const { return _goal; }
std::vector<float> & distance() { return _distance; }
std::vector<int> & path() { return _path; }
std::vector<float> distance() const { return _distance; }
std::vector<int> path() const { return _path; }
void stats(const std::string &fname) const {
std::ofstream of(fname);
of << stats_str();
}
std::string stats_str() const {
std::stringstream ss;
ss << "nodes: " << _wg.num_nodes() << "\n";
ss << "edges: " << _wg.num_edges() << "\n";
ss << "root: " << _root << "\n";
ss << "goal: " << _goal << "\n";
ss << "traversed edges: " << _traversed_edges << "\n";
ss << "fp compares: " << _fp_compares << "\n";
ss << "fp adds: " << _fp_adds << "\n";
ss << "fp total: " << _fp_compares+_fp_adds << "\n";
ss << "fp total analytical: " << 2 * (_wg.num_nodes()-1) * _wg.num_edges() << "\n";
ss << "distance (root->goal): " << _distance[_goal] << "\n";
return ss.str();
}
static int Test(int argc, char *argv[]) {
std::pair<int,int> graph =
{10*1000, 32*1000}
//{10*1000, 320*1000}
//{20*1000, 500*1000}
;
int goal =
//8504
//2921
//3091
//1190
4604
//7550
//9199
//7550
//1504
//861
;
auto wg = WGraph::Uniform(graph.first, graph.second);
FullWorldDijkstra fdijkstra(wg, 0, goal);
fdijkstra.run();
std::cout << "stats:" << std::endl;
std::cout << fdijkstra.stats_str() << std::endl;
return 0;
}
private:
WGraph _wg;
int _root;
int _goal;
int _traversed_edges;
int _fp_compares;
int _fp_adds;
std::vector<float> _distance;
std::vector<int> _path;
std::vector<int> _teps_to_find;
};