ensure all outer vertices are scanned
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1 changed files with 89 additions and 77 deletions
166
src/edmonds.cpp
166
src/edmonds.cpp
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@ -30,101 +30,113 @@ std::vector<NodeId> path_to_forest_root(Graph const & graph, NodeId id)
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return retval;
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return retval;
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}
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}
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NodeId find_outer_vertex(Graph const & graph)
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{
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for(NodeId id = 0; id < graph.num_nodes(); ++id)
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{
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if (not graph.node(id).scanned and graph.is_outer(id))
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{
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return id;
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}
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}
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return invalid_node_id;
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}
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Graph maximum_matching_from_initial_matching(Graph & graph)
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Graph maximum_matching_from_initial_matching(Graph & graph)
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{
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{
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graph.reset_forest();
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graph.reset_forest();
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for(NodeId id = 0; id < graph.num_nodes(); ++id) {
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NodeId id;
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if (graph.is_outer(id))
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while((id = find_outer_vertex(graph)) != invalid_node_id)
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{
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for(NodeId neighbor_id : graph.node(id).neighbors())
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{
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{
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for(NodeId neighbor_id : graph.node(id).neighbors())
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if (graph.is_out_of_forest(neighbor_id))
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{
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{
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if (graph.is_out_of_forest(neighbor_id))
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// Grow Forest
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{
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graph.node(neighbor_id).ear_or_root_neighbor = id;
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// Grow Forest
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}
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graph.node(neighbor_id).ear_or_root_neighbor = id;
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else if (graph.is_outer(neighbor_id) and \
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}
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graph.root_of_ear_component(id) != graph.root_of_ear_component(neighbor_id))
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else if (graph.is_outer(neighbor_id) and \
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{
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graph.root_of_ear_component(id) != graph.root_of_ear_component(neighbor_id))
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std::vector<NodeId> x_path = path_to_forest_root(graph, id);
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{
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std::vector<NodeId> y_path = path_to_forest_root(graph, neighbor_id);
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std::vector<NodeId> x_path = path_to_forest_root(graph, id);
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std::vector<NodeId> y_path = path_to_forest_root(graph, neighbor_id);
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if (x_path.back() != y_path.back())
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if (x_path.back() != y_path.back())
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{
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// Paths are disjoint -> augment
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graph.node(x_path.front()).matched_neighbor = y_path.front();
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graph.node(y_path.front()).matched_neighbor = x_path.front();
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// TODO: put this into own method?
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for(size_t i = 1; i < x_path.size(); i += 2)
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{
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{
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// Paths are disjoint -> augment
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graph.node(x_path[i]).matched_neighbor = x_path[i+1];
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graph.node(x_path.front()).matched_neighbor = y_path.front();
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graph.node(x_path[i+1]).matched_neighbor = x_path[i];
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graph.node(y_path.front()).matched_neighbor = x_path.front();
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// TODO: put this into own method?
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for(size_t i = 1; i < x_path.size(); i += 2)
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{
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graph.node(x_path[i]).matched_neighbor = x_path[i+1];
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graph.node(x_path[i+1]).matched_neighbor = x_path[i];
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}
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for(size_t i = 1; i < y_path.size(); i += 2)
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{
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graph.node(y_path[i]).matched_neighbor = y_path[i+1];
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graph.node(y_path[i+1]).matched_neighbor = y_path[i];
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}
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// Note that since this is tail-recursion, this will not generate
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// new stack frames in OPT mode
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return maximum_matching(graph);
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}
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}
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else
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for(size_t i = 1; i < y_path.size(); i += 2)
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{
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{
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// Paths are not disjoint -> shrink blossom
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graph.node(y_path[i]).matched_neighbor = y_path[i+1];
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size_t distance_from_x = x_path.size() - 1;
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graph.node(y_path[i+1]).matched_neighbor = y_path[i];
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size_t distance_from_y = y_path.size() - 1;
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}
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while (distance_from_x > 0 and distance_from_y > 0 and \
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// Note that since this is tail-recursion, this will not generate
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x_path[distance_from_x - 1] == y_path[distance_from_y - 1])
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// new stack frames in OPT mode
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return maximum_matching(graph);
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}
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else
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{
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// Paths are not disjoint -> shrink blossom
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size_t distance_from_x = x_path.size() - 1;
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size_t distance_from_y = y_path.size() - 1;
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while (distance_from_x > 0 and distance_from_y > 0 and \
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x_path[distance_from_x - 1] == y_path[distance_from_y - 1])
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{
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--distance_from_x;
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--distance_from_y;
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}
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// found first vertex of x_path \cap y_path
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while (graph.root_of_ear_component(x_path[distance_from_x]) != x_path[distance_from_x])
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{
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++distance_from_x;
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++distance_from_y;
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};
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// found first vertex fixed by root_of_ear_component
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NodeId blossom_root_id = x_path[distance_from_x];
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for(size_t i = 1; i <= distance_from_x; i += 2)
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{
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if (graph.root_of_ear_component(graph.ear_or_root_neighbor(x_path[i])) != blossom_root_id)
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{
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{
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--distance_from_x;
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graph.node(graph.ear_or_root_neighbor(x_path[i])).ear_or_root_neighbor = x_path[i];
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--distance_from_y;
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}
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}
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// found first vertex of x_path \cap y_path
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}
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while (graph.root_of_ear_component(x_path[distance_from_x]) != x_path[distance_from_x])
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for(size_t i = 1; i <= distance_from_y; i += 2)
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{
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if (graph.root_of_ear_component(graph.ear_or_root_neighbor(y_path[i])) != blossom_root_id)
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{
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{
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++distance_from_x;
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graph.node(graph.ear_or_root_neighbor(y_path[i])).ear_or_root_neighbor = y_path[i];
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++distance_from_y;
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};
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// found first vertex fixed by root_of_ear_component
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NodeId blossom_root_id = x_path[distance_from_x];
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for(size_t i = 1; i <= distance_from_x; i += 2)
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{
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if (graph.root_of_ear_component(graph.ear_or_root_neighbor(x_path[i])) != blossom_root_id)
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{
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graph.node(graph.ear_or_root_neighbor(x_path[i])).ear_or_root_neighbor = x_path[i];
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}
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}
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for(size_t i = 1; i <= distance_from_y; i += 2)
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{
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if (graph.root_of_ear_component(graph.ear_or_root_neighbor(y_path[i])) != blossom_root_id)
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{
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graph.node(graph.ear_or_root_neighbor(y_path[i])).ear_or_root_neighbor = y_path[i];
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}
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}
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if (graph.root_of_ear_component(x_path.front()) != blossom_root_id)
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{
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graph.node(x_path.front()).ear_or_root_neighbor = y_path.front();
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}
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if (graph.root_of_ear_component(y_path.front()) != blossom_root_id)
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{
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graph.node(x_path.front()).ear_or_root_neighbor = x_path.front();
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}
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}
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}
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if (graph.root_of_ear_component(x_path.front()) != blossom_root_id)
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{
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graph.node(x_path.front()).ear_or_root_neighbor = y_path.front();
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}
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if (graph.root_of_ear_component(y_path.front()) != blossom_root_id)
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{
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graph.node(x_path.front()).ear_or_root_neighbor = x_path.front();
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}
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// Update root indices
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// Update root indices
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for(size_t i = 0; i <= distance_from_x; ++i)
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for(size_t i = 0; i <= distance_from_x; ++i)
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{
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{
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graph.node(x_path[i]).root_of_ear_component = blossom_root_id;
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graph.node(x_path[i]).root_of_ear_component = blossom_root_id;
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}
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}
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for(size_t i = 0; i <= distance_from_y; ++i)
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for(size_t i = 0; i <= distance_from_y; ++i)
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{
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{
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graph.node(y_path[i]).root_of_ear_component = blossom_root_id;
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graph.node(y_path[i]).root_of_ear_component = blossom_root_id;
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}
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}
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}
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}
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}
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}
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}
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}
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}
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graph.node(id).scanned = true;
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}
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}
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return graph;
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return graph;
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};
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};
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