259 lines
7.7 KiB
C++
259 lines
7.7 KiB
C++
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// Copyright 2017, University of Freiburg,
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// Chair of Algorithms and Data Structures.
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// Authors: Patrick Brosi <brosi@informatik.uni-freiburg.de>
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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C EDijkstra::shortestPathImpl(Node<N, E>* from, const std::set<Node<N, E>*>& to,
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const ShortestPath::CostFunc<N, E, C>& costFunc,
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const ShortestPath::HeurFunc<N, E, C>& heurFunc,
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EList<N, E>* resEdges, NList<N, E>* resNodes) {
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std::set<Edge<N, E>*> frEs;
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std::set<Edge<N, E>*> toEs;
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frEs.insert(from->getAdjListOut().begin(), from->getAdjListOut().end());
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for (auto n : to) {
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toEs.insert(n->getAdjListIn().begin(), n->getAdjListIn().end());
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}
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C cost = shortestPathImpl(frEs, toEs, costFunc, heurFunc, resEdges, resNodes);
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// the beginning node is not included in our edge based dijkstra
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if (resNodes) resNodes->push_back(from);
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return cost;
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}
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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C EDijkstra::shortestPathImpl(Edge<N, E>* from, const std::set<Node<N, E>*>& to,
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const ShortestPath::CostFunc<N, E, C>& costFunc,
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const ShortestPath::HeurFunc<N, E, C>& heurFunc,
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EList<N, E>* resEdges, NList<N, E>* resNodes) {
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std::set<Edge<N, E>*> frEs;
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std::set<Edge<N, E>*> toEs;
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frEs.insert(from);
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for (auto n : to) {
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toEs.insert(n->getAdjListIn().begin(), n->getAdjListIn().end());
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}
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C cost = shortestPathImpl(frEs, toEs, costFunc, heurFunc, resEdges, resNodes);
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return cost;
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}
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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C EDijkstra::shortestPathImpl(const std::set<Edge<N, E>*> from,
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const std::set<Edge<N, E>*>& to,
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const ShortestPath::CostFunc<N, E, C>& costFunc,
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const ShortestPath::HeurFunc<N, E, C>& heurFunc,
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EList<N, E>* resEdges, NList<N, E>* resNodes) {
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if (from.size() == 0 || to.size() == 0) return costFunc.inf();
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Settled<N, E, C> settled;
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PQ<N, E, C> pq;
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bool found = false;
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// at the beginning, put all edges on the priority queue,
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// init them with their own cost
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for (auto e : from) {
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C c = costFunc(0, 0, e);
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C h = heurFunc(e, to);
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pq.emplace(e, (Edge<N, E>*)0, (Node<N, E>*)0, c, c + h);
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}
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RouteEdge<N, E, C> cur;
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while (!pq.empty()) {
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EDijkstra::ITERS++;
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if (settled.find(pq.top().e) != settled.end()) {
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pq.pop();
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continue;
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}
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cur = pq.top();
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pq.pop();
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settled[cur.e] = cur;
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if (to.find(cur.e) != to.end()) {
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found = true;
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break;
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}
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relax(cur, to, costFunc, heurFunc, pq);
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}
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if (!found) return costFunc.inf();
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buildPath(cur.e, settled, resNodes, resEdges);
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return cur.d;
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}
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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std::unordered_map<Edge<N, E>*, C> EDijkstra::shortestPathImpl(
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const std::set<Edge<N, E>*>& from, const ShortestPath::CostFunc<N, E, C>& costFunc,
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bool rev) {
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std::unordered_map<Edge<N, E>*, C> costs;
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Settled<N, E, C> settled;
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PQ<N, E, C> pq;
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std::set<Edge<N, E>*> to;
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for (auto e : from) {
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pq.emplace(e, (Edge<N, E>*)0, (Node<N, E>*)0, costFunc(0, 0, e), C());
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}
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RouteEdge<N, E, C> cur;
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while (!pq.empty()) {
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EDijkstra::ITERS++;
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if (settled.find(pq.top().e) != settled.end()) {
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pq.pop();
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continue;
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}
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cur = pq.top();
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pq.pop();
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settled[cur.e] = cur;
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costs[cur.e] = cur.d;
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buildPath(cur.e, settled, (NList<N, E>*)0, (EList<N, E>*)0);
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if (rev)
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relaxInv(cur, costFunc, pq);
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else
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relax(cur, to, costFunc, ZeroHeurFunc<N, E, C>(), pq);
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}
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return costs;
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}
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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std::unordered_map<Edge<N, E>*, C> EDijkstra::shortestPathImpl(
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Edge<N, E>* from, const std::set<Edge<N, E>*>& to,
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const ShortestPath::CostFunc<N, E, C>& costFunc,
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const ShortestPath::HeurFunc<N, E, C>& heurFunc,
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std::unordered_map<Edge<N, E>*, EList<N, E>*> resEdges,
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std::unordered_map<Edge<N, E>*, NList<N, E>*> resNodes) {
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std::unordered_map<Edge<N, E>*, C> costs;
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if (to.size() == 0) return costs;
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// init costs with inf
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for (auto e : to) costs[e] = costFunc.inf();
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Settled<N, E, C> settled;
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PQ<N, E, C> pq;
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size_t found = 0;
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C c = costFunc(0, 0, from);
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C h = heurFunc(from, to);
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pq.emplace(from, (Edge<N, E>*)0, (Node<N, E>*)0, c, c + h);
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RouteEdge<N, E, C> cur;
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while (!pq.empty()) {
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EDijkstra::ITERS++;
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if (settled.find(pq.top().e) != settled.end()) {
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pq.pop();
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continue;
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}
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cur = pq.top();
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pq.pop();
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settled[cur.e] = cur;
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if (to.find(cur.e) != to.end()) {
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found++;
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costs[cur.e] = cur.d;
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buildPath(cur.e, settled, resNodes[cur.e], resEdges[cur.e]);
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}
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if (found == to.size()) return costs;
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relax(cur, to, costFunc, heurFunc, pq);
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}
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return costs;
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}
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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void EDijkstra::relaxInv(RouteEdge<N, E, C>& cur,
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const ShortestPath::CostFunc<N, E, C>& costFunc,
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PQ<N, E, C>& pq) {
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// handling undirected graph makes no sense here
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for (const auto edge : cur.e->getFrom()->getAdjListIn()) {
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if (edge == cur.e) continue;
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C newC = costFunc(edge, cur.e->getFrom(), cur.e);
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newC = cur.d + newC;
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if (costFunc.inf() <= newC) continue;
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pq.emplace(edge, cur.e, cur.e->getFrom(), newC, C());
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}
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}
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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void EDijkstra::relax(RouteEdge<N, E, C>& cur, const std::set<Edge<N, E>*>& to,
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const ShortestPath::CostFunc<N, E, C>& costFunc,
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const ShortestPath::HeurFunc<N, E, C>& heurFunc,
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PQ<N, E, C>& pq) {
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if (cur.e->getFrom()->hasEdgeIn(cur.e)) {
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// for undirected graphs
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for (const auto edge : cur.e->getFrom()->getAdjListOut()) {
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if (edge == cur.e) continue;
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C newC = costFunc(cur.e, cur.e->getFrom(), edge);
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newC = cur.d + newC;
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if (costFunc.inf() <= newC) continue;
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const C& h = heurFunc(edge, to);
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const C& newH = newC + h;
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pq.emplace(edge, cur.e, cur.e->getFrom(), newC, newH);
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}
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}
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for (const auto edge : cur.e->getTo()->getAdjListOut()) {
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if (edge == cur.e) continue;
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C newC = costFunc(cur.e, cur.e->getTo(), edge);
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newC = cur.d + newC;
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if (costFunc.inf() <= newC) continue;
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const C& h = heurFunc(edge, to);
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const C& newH = newC + h;
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pq.emplace(edge, cur.e, cur.e->getTo(), newC, newH);
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}
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}
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// _____________________________________________________________________________
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template <typename N, typename E, typename C>
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void EDijkstra::buildPath(Edge<N, E>* curE, const Settled<N, E, C>& settled,
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NList<N, E>* resNodes, EList<N, E>* resEdges) {
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const RouteEdge<N, E, C>* curEdge = &settled.find(curE)->second;
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if (resNodes) resNodes->push_back(curEdge->e->getOtherNd(curEdge->n));
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while (true) {
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if (resNodes && curEdge->n) resNodes->push_back(curEdge->n);
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if (resEdges) resEdges->push_back(curEdge->e);
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if (!curEdge->parent) break;
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curEdge = &settled.find(curEdge->parent)->second;
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}
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}
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