1 // Ceres Solver - A fast non-linear least squares minimizer 2 // Copyright 2010, 2011, 2012 Google Inc. All rights reserved. 3 // http://code.google.com/p/ceres-solver/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are met: 7 // 8 // * Redistributions of source code must retain the above copyright notice, 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 12 // and/or other materials provided with the distribution. 13 // * Neither the name of Google Inc. nor the names of its contributors may be 14 // used to endorse or promote products derived from this software without 15 // specific prior written permission. 16 // 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 20 // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 21 // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 // POSSIBILITY OF SUCH DAMAGE. 28 // 29 // Author: sameeragarwal (at) google.com (Sameer Agarwal) 30 31 #ifndef CERES_INTERNAL_GRAPH_H_ 32 #define CERES_INTERNAL_GRAPH_H_ 33 34 #include <limits> 35 #include <glog/logging.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 42 namespace ceres { 43 namespace internal { 44 45 // A weighted undirected graph templated over the vertex ids. Vertex 46 // should be hashable and comparable. 47 template <typename Vertex> 48 class Graph { 49 public: 50 Graph() {} 51 52 // Add a weighted vertex. If the vertex already exists in the graph, 53 // its weight is set to the new weight. 54 void AddVertex(const Vertex& vertex, double weight) { 55 if (vertices_.find(vertex) == vertices_.end()) { 56 vertices_.insert(vertex); 57 edges_[vertex] = HashSet<Vertex>(); 58 } 59 vertex_weights_[vertex] = weight; 60 } 61 62 // Uses weight = 1.0. If vertex already exists, its weight is set to 63 // 1.0. 64 void AddVertex(const Vertex& vertex) { 65 AddVertex(vertex, 1.0); 66 } 67 68 bool RemoveVertex(const Vertex& vertex) { 69 if (vertices_.find(vertex) == vertices_.end()) { 70 return false; 71 } 72 73 vertices_.erase(vertex); 74 vertex_weights_.erase(vertex); 75 const HashSet<Vertex>& sinks = edges_[vertex]; 76 for (typename HashSet<Vertex>::const_iterator it = sinks.begin(); 77 it != sinks.end(); ++it) { 78 if (vertex < *it) { 79 edge_weights_.erase(make_pair(vertex, *it)); 80 } else { 81 edge_weights_.erase(make_pair(*it, vertex)); 82 } 83 edges_[*it].erase(vertex); 84 } 85 86 edges_.erase(vertex); 87 return true; 88 } 89 90 // Add a weighted edge between the vertex1 and vertex2. Calling 91 // AddEdge on a pair of vertices which do not exist in the graph yet 92 // will result in undefined behavior. 93 // 94 // It is legal to call this method repeatedly for the same set of 95 // vertices. 96 void AddEdge(const Vertex& vertex1, const Vertex& vertex2, double weight) { 97 DCHECK(vertices_.find(vertex1) != vertices_.end()); 98 DCHECK(vertices_.find(vertex2) != vertices_.end()); 99 100 if (edges_[vertex1].insert(vertex2).second) { 101 edges_[vertex2].insert(vertex1); 102 } 103 104 if (vertex1 < vertex2) { 105 edge_weights_[make_pair(vertex1, vertex2)] = weight; 106 } else { 107 edge_weights_[make_pair(vertex2, vertex1)] = weight; 108 } 109 } 110 111 // Uses weight = 1.0. 112 void AddEdge(const Vertex& vertex1, const Vertex& vertex2) { 113 AddEdge(vertex1, vertex2, 1.0); 114 } 115 116 // Calling VertexWeight on a vertex not in the graph will result in 117 // undefined behavior. 118 double VertexWeight(const Vertex& vertex) const { 119 return FindOrDie(vertex_weights_, vertex); 120 } 121 122 // Calling EdgeWeight on a pair of vertices where either one of the 123 // vertices is not present in the graph will result in undefined 124 // behaviour. If there is no edge connecting vertex1 and vertex2, 125 // the edge weight is zero. 126 double EdgeWeight(const Vertex& vertex1, const Vertex& vertex2) const { 127 if (vertex1 < vertex2) { 128 return FindWithDefault(edge_weights_, make_pair(vertex1, vertex2), 0.0); 129 } else { 130 return FindWithDefault(edge_weights_, make_pair(vertex2, vertex1), 0.0); 131 } 132 } 133 134 // Calling Neighbors on a vertex not in the graph will result in 135 // undefined behaviour. 136 const HashSet<Vertex>& Neighbors(const Vertex& vertex) const { 137 return FindOrDie(edges_, vertex); 138 } 139 140 const HashSet<Vertex>& vertices() const { 141 return vertices_; 142 } 143 144 static double InvalidWeight() { 145 return std::numeric_limits<double>::quiet_NaN(); 146 }; 147 148 private: 149 HashSet<Vertex> vertices_; 150 HashMap<Vertex, double> vertex_weights_; 151 HashMap<Vertex, HashSet<Vertex> > edges_; 152 HashMap<pair<Vertex, Vertex>, double> edge_weights_; 153 154 CERES_DISALLOW_COPY_AND_ASSIGN(Graph); 155 }; 156 157 } // namespace internal 158 } // namespace ceres 159 160 #endif // CERES_INTERNAL_GRAPH_H_ 161
