1 // Ceres Solver - A fast non-linear least squares minimizer
2 // Copyright 2015 Google Inc. All rights reserved.
3 // http://ceres-solver.org/
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6 // modification, are permitted provided that the following conditions are met:
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9 // this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above copyright notice,
11 // this list of conditions and the following disclaimer in the documentation
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14 // used to endorse or promote products derived from this software without
15 // specific prior written permission.
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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24 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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29 // Author: sameeragarwal@google.com (Sameer Agarwal)
31 #ifndef CERES_INTERNAL_GRAPH_H_
32 #define CERES_INTERNAL_GRAPH_H_
36 #include "ceres/integral_types.h"
37 #include "ceres/map_util.h"
38 #include "ceres/collections_port.h"
39 #include "ceres/internal/macros.h"
40 #include "ceres/types.h"
41 #include "glog/logging.h"
46 // A unweighted undirected graph templated over the vertex ids. Vertex
47 // should be hashable.
48 template <typename Vertex>
54 void AddVertex(const Vertex& vertex) {
55 if (vertices_.insert(vertex).second) {
56 edges_[vertex] = HashSet<Vertex>();
60 bool RemoveVertex(const Vertex& vertex) {
61 if (vertices_.find(vertex) == vertices_.end()) {
65 vertices_.erase(vertex);
66 const HashSet<Vertex>& sinks = edges_[vertex];
67 for (typename HashSet<Vertex>::const_iterator it = sinks.begin();
68 it != sinks.end(); ++it) {
69 edges_[*it].erase(vertex);
76 // Add an edge between the vertex1 and vertex2. Calling AddEdge on a
77 // pair of vertices which do not exist in the graph yet will result
78 // in undefined behavior.
80 // It is legal to call this method repeatedly for the same set of
82 void AddEdge(const Vertex& vertex1, const Vertex& vertex2) {
83 DCHECK(vertices_.find(vertex1) != vertices_.end());
84 DCHECK(vertices_.find(vertex2) != vertices_.end());
86 if (edges_[vertex1].insert(vertex2).second) {
87 edges_[vertex2].insert(vertex1);
91 // Calling Neighbors on a vertex not in the graph will result in
92 // undefined behaviour.
93 const HashSet<Vertex>& Neighbors(const Vertex& vertex) const {
94 return FindOrDie(edges_, vertex);
97 const HashSet<Vertex>& vertices() const {
102 HashSet<Vertex> vertices_;
103 HashMap<Vertex, HashSet<Vertex> > edges_;
105 CERES_DISALLOW_COPY_AND_ASSIGN(Graph);
108 // A weighted undirected graph templated over the vertex ids. Vertex
109 // should be hashable and comparable.
110 template <typename Vertex>
111 class WeightedGraph {
115 // Add a weighted vertex. If the vertex already exists in the graph,
116 // its weight is set to the new weight.
117 void AddVertex(const Vertex& vertex, double weight) {
118 if (vertices_.find(vertex) == vertices_.end()) {
119 vertices_.insert(vertex);
120 edges_[vertex] = HashSet<Vertex>();
122 vertex_weights_[vertex] = weight;
125 // Uses weight = 1.0. If vertex already exists, its weight is set to
127 void AddVertex(const Vertex& vertex) {
128 AddVertex(vertex, 1.0);
131 bool RemoveVertex(const Vertex& vertex) {
132 if (vertices_.find(vertex) == vertices_.end()) {
136 vertices_.erase(vertex);
137 vertex_weights_.erase(vertex);
138 const HashSet<Vertex>& sinks = edges_[vertex];
139 for (typename HashSet<Vertex>::const_iterator it = sinks.begin();
140 it != sinks.end(); ++it) {
142 edge_weights_.erase(std::make_pair(vertex, *it));
144 edge_weights_.erase(std::make_pair(*it, vertex));
146 edges_[*it].erase(vertex);
149 edges_.erase(vertex);
153 // Add a weighted edge between the vertex1 and vertex2. Calling
154 // AddEdge on a pair of vertices which do not exist in the graph yet
155 // will result in undefined behavior.
157 // It is legal to call this method repeatedly for the same set of
159 void AddEdge(const Vertex& vertex1, const Vertex& vertex2, double weight) {
160 DCHECK(vertices_.find(vertex1) != vertices_.end());
161 DCHECK(vertices_.find(vertex2) != vertices_.end());
163 if (edges_[vertex1].insert(vertex2).second) {
164 edges_[vertex2].insert(vertex1);
167 if (vertex1 < vertex2) {
168 edge_weights_[std::make_pair(vertex1, vertex2)] = weight;
170 edge_weights_[std::make_pair(vertex2, vertex1)] = weight;
174 // Uses weight = 1.0.
175 void AddEdge(const Vertex& vertex1, const Vertex& vertex2) {
176 AddEdge(vertex1, vertex2, 1.0);
179 // Calling VertexWeight on a vertex not in the graph will result in
180 // undefined behavior.
181 double VertexWeight(const Vertex& vertex) const {
182 return FindOrDie(vertex_weights_, vertex);
185 // Calling EdgeWeight on a pair of vertices where either one of the
186 // vertices is not present in the graph will result in undefined
187 // behaviour. If there is no edge connecting vertex1 and vertex2,
188 // the edge weight is zero.
189 double EdgeWeight(const Vertex& vertex1, const Vertex& vertex2) const {
190 if (vertex1 < vertex2) {
191 return FindWithDefault(edge_weights_,
192 std::make_pair(vertex1, vertex2), 0.0);
194 return FindWithDefault(edge_weights_,
195 std::make_pair(vertex2, vertex1), 0.0);
199 // Calling Neighbors on a vertex not in the graph will result in
200 // undefined behaviour.
201 const HashSet<Vertex>& Neighbors(const Vertex& vertex) const {
202 return FindOrDie(edges_, vertex);
205 const HashSet<Vertex>& vertices() const {
209 static double InvalidWeight() {
210 return std::numeric_limits<double>::quiet_NaN();
214 HashSet<Vertex> vertices_;
215 HashMap<Vertex, double> vertex_weights_;
216 HashMap<Vertex, HashSet<Vertex> > edges_;
217 HashMap<std::pair<Vertex, Vertex>, double> edge_weights_;
219 CERES_DISALLOW_COPY_AND_ASSIGN(WeightedGraph);
222 } // namespace internal
225 #endif // CERES_INTERNAL_GRAPH_H_