132 lines
4.2 KiB
C++
132 lines
4.2 KiB
C++
/*
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* Copyright 2016 The Cartographer Authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "cartographer/mapping/connected_components.h"
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#include <algorithm>
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#include <unordered_set>
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#include "cartographer/mapping/proto/connected_components.pb.h"
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#include "glog/logging.h"
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namespace cartographer {
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namespace mapping {
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ConnectedComponents::ConnectedComponents()
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: lock_(), forest_(), connection_map_() {}
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void ConnectedComponents::Add(const int trajectory_id) {
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common::MutexLocker locker(&lock_);
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forest_.emplace(trajectory_id, trajectory_id);
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}
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void ConnectedComponents::Connect(const int trajectory_id_a,
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const int trajectory_id_b) {
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common::MutexLocker locker(&lock_);
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Union(trajectory_id_a, trajectory_id_b);
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auto sorted_pair = std::minmax(trajectory_id_a, trajectory_id_b);
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++connection_map_[sorted_pair];
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}
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void ConnectedComponents::Union(const int trajectory_id_a,
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const int trajectory_id_b) {
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forest_.emplace(trajectory_id_a, trajectory_id_a);
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forest_.emplace(trajectory_id_b, trajectory_id_b);
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const int representative_a = FindSet(trajectory_id_a);
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const int representative_b = FindSet(trajectory_id_b);
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forest_[representative_a] = representative_b;
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}
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int ConnectedComponents::FindSet(const int trajectory_id) {
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auto it = forest_.find(trajectory_id);
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CHECK(it != forest_.end());
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if (it->first != it->second) {
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it->second = FindSet(it->second);
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}
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return it->second;
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}
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bool ConnectedComponents::TransitivelyConnected(const int trajectory_id_a,
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const int trajectory_id_b) {
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if (trajectory_id_a == trajectory_id_b) {
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return true;
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}
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common::MutexLocker locker(&lock_);
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if (forest_.count(trajectory_id_a) == 0 ||
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forest_.count(trajectory_id_b) == 0) {
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return false;
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}
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return FindSet(trajectory_id_a) == FindSet(trajectory_id_b);
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}
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std::vector<std::vector<int>> ConnectedComponents::Components() {
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// Map from cluster exemplar -> growing cluster.
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std::unordered_map<int, std::vector<int>> map;
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common::MutexLocker locker(&lock_);
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for (const auto& trajectory_id_entry : forest_) {
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map[FindSet(trajectory_id_entry.first)].push_back(
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trajectory_id_entry.first);
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}
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std::vector<std::vector<int>> result;
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result.reserve(map.size());
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for (auto& pair : map) {
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result.emplace_back(std::move(pair.second));
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}
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return result;
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}
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std::vector<int> ConnectedComponents::GetComponent(const int trajectory_id) {
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common::MutexLocker locker(&lock_);
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const int set_id = FindSet(trajectory_id);
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std::vector<int> trajectory_ids;
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for (const auto& entry : forest_) {
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if (FindSet(entry.first) == set_id) {
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trajectory_ids.push_back(entry.first);
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}
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}
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return trajectory_ids;
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}
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int ConnectedComponents::ConnectionCount(const int trajectory_id_a,
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const int trajectory_id_b) {
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common::MutexLocker locker(&lock_);
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const auto it =
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connection_map_.find(std::minmax(trajectory_id_a, trajectory_id_b));
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return it != connection_map_.end() ? it->second : 0;
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}
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proto::ConnectedComponents ToProto(
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std::vector<std::vector<int>> connected_components) {
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proto::ConnectedComponents proto;
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for (auto& connected_component : connected_components) {
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std::sort(connected_component.begin(), connected_component.end());
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}
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std::sort(connected_components.begin(), connected_components.end());
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for (const auto& connected_component : connected_components) {
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auto* proto_connected_component = proto.add_connected_component();
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for (const int trajectory_id : connected_component) {
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proto_connected_component->add_trajectory_id(trajectory_id);
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}
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}
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return proto;
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}
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} // namespace mapping
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} // namespace cartographer
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