这是我提出的关于提升图的另一个问题的延续。(GraphML in Boost)。成功阅读图表后,我正在尝试在一些随机开始和目标节点上应用 boost A*,但它的抛出分割错误。
以下是我的图表的细节。
using Graph = boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS, VertexProperties, EdgeProperties>;
struct VertexProperties {
std::vector<double> joint_angles;
VertexProperties() : joint_angles(3){}
};
struct EdgeProperties {
double weight;
};
我使用 Boost 中的 A* 城市文件作为参考(A* 城市)来编码我的距离启发式和astar_goal_visitor。
struct found_goal {}; // exception for termination
// visitor that terminates when we find the goal
template <typename Vertex>
class astar_goal_visitor : public boost::default_astar_visitor
{
public:
astar_goal_visitor(Vertex goal) : m_goal(goal) {}
template <class Graph>
void examine_vertex(Vertex u, Graph& g) {
if(u == m_goal)
throw found_goal();
}
private:
Vertex m_goal;
};
// euclidean distance heuristic
template <class Graph>
class distance_heuristic : public boost::astar_heuristic<typename Graph::Graph, double>
{
public:
typedef typename boost::graph_traits<typename Graph::Graph>::vertex_descriptor Vertex;
distance_heuristic(Vertex goal, Graph &graph)
: m_goal(goal), m_graph(graph) {}
double operator()(Vertex u)
{
double dx = m_graph.getGraph()[m_goal].joint_angles[0] - m_graph.getGraph()[u].joint_angles[0];
double dy = m_graph.getGraph()[m_goal].joint_angles[1] - m_graph.getGraph()[u].joint_angles[1];
double dz = m_graph.getGraph()[m_goal].joint_angles[2] - m_graph.getGraph()[u].joint_angles[2];
return ::sqrt(dx * dx + dy * dy + dz * dz);
}
private:
Graph m_graph;
Vertex m_goal;
};
至于astar_search参数,前身映射定义如下。
typedef boost::property_map < Graph, boost::vertex_index_t >::type IndexMap;
typedef boost::iterator_property_map < Vertex*, IndexMap, Vertex, Vertex& > PredecessorMap;
BoostGraph::PredecessorMap BoostGraph::getPredecessorMap(){
IndexMap indexMap = boost::get(boost::vertex_index, graph);
std::vector<Vertex> p(boost::num_vertices(graph));
PredecessorMap predecessorMap(&p[0], indexMap);
return predecessorMap;
}
搜索的最终代码是
std::vector<double> d(boost::num_vertices(graph.getGraph()));
std::mt19937 gen(time(0));
BoostGraph::Vertex start = boost::random_vertex(graph.getGraph(), gen);
BoostGraph::Vertex goal = boost::random_vertex(graph.getGraph(), gen);
auto weightmap = boost::get(&EdgeProperties::weight, graph.getGraph());
try {
// call astar named parameter interface
boost::astar_search
(graph.getGraph(), start,
distance_heuristic<BoostGraph>
(goal, graph),
boost::predecessor_map(graph.getPredecessorMap()).distance_map(boost::make_iterator_property_map(d.begin(), boost::get(boost::vertex_index, graph.getGraph()))).
weight_map(weightmap).
visitor(astar_goal_visitor<BoostGraph::Vertex>(goal)));
} catch(found_goal fg) { // found a path to the goal
std::list<BoostGraph::Vertex> shortest_path;
for(BoostGraph::Vertex v = goal;; v = p[v]) {
shortest_path.push_front(v);
if(p[v] == v)
break;
}
}
在下面定义了类BoostG想像的getG想像函数,其中FIG是类BoostG想像的受保护成员。
protected:
Graph graph;
const BoostGraph::Graph& BoostGraph::getGraph() const{
return graph;
}
分段错误出现在stl_tree.h中,我不知道哪里出错了。任何帮助都将不胜感激。谢谢
>
您的启发式方法包含图形的副本。您正在使用属于不同图形的顶点描述符进行索引。
您的前任映射是一个局部变量(vector),在< code>getPredecessorMap返回后,该映射是对它的悬空引用。只要让vector成为成员,然后< code>getPredecessorMap就可以消除了,因为它并没有真正增加多少。
此外,您正在索引到< code>joint_angles中,而没有边界检查。首选<代码>。如果您想更安全,请在< code>[n]上方的(n)处。事实上,可以考虑使用< code>std::array
总而言之,我的印象是你一直在试图隐藏类和成员函数中的复杂性,但它会导致代码变得碎片化并引发许多不必要的生命周期问题。
还有一些代码没有显示。它们可能存在更多问题(例如,getGraph()
至关重要)。
以下是我的简化观点:
科里鲁
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/astar_search.hpp>
#include <boost/graph/random.hpp>
using JointAngles = std::vector<double>;
struct VertexProperties {
JointAngles joint_angles{0, 0, 0};
};
struct EdgeProperties {
double weight = 0;
};
using Graph = boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS,
VertexProperties, EdgeProperties>;
using Vertex = Graph::vertex_descriptor;
// visitor that terminates when we find the goal
struct goal_visitor : boost::default_astar_visitor {
struct found {}; // exception for termination
Vertex m_goal;
goal_visitor(Vertex g) : m_goal(g) {}
template <class Graph> void examine_vertex(Vertex u, Graph&) {
if (u == m_goal)
throw found{};
}
};
// euclidean distance heuristic
struct distance_heuristic : boost::astar_heuristic<Graph, double> {
distance_heuristic(Vertex goal, Graph& graph)
: m_graph(graph)
, m_goal(graph[goal].joint_angles) {}
double operator()(Vertex u) const {
auto& c = m_graph[u].joint_angles;
auto //
dx = m_goal.at(0) - c.at(0), //
dy = m_goal.at(1) - c.at(1), //
dz = m_goal.at(2) - c.at(2);
using std::sqrt; // allow ADL, good practice
return sqrt(dx * dx + dy * dy + dz * dz);
}
private:
Graph& m_graph; // reference!
JointAngles m_goal;
};
#include <random>
#include <fmt/ranges.h>
int main() {
Graph graph(4);
graph[0] = VertexProperties{{0, 0, 0}};
graph[1] = VertexProperties{{1, 1, 1}};
graph[2] = VertexProperties{{2, 2, 2}};
add_edge(0, 1, graph);
add_edge(1, 2, graph);
std::vector<Vertex> predecessors(num_vertices(graph));
std::vector<double> distances(num_vertices(graph));
auto index = get(boost::vertex_index, graph);
auto pmap = make_safe_iterator_property_map(predecessors.begin(), predecessors.size(), index);
auto dmap = make_safe_iterator_property_map(distances.begin(), distances.size(), index);
auto weightmap = get(&EdgeProperties::weight, graph);
std::mt19937 gen(std::random_device{}());
Vertex start = random_vertex(graph, gen);
Vertex goal = random_vertex(graph, gen);
try {
// call astar named parameter interface
astar_search( //
graph, start, distance_heuristic{goal, graph},
boost::predecessor_map(pmap) //
.distance_map(dmap)
.weight_map(weightmap)
.visitor(goal_visitor{goal}));
fmt::print("{} -> {}: No path\n", start, goal);
} catch (goal_visitor::found) {
std::list<Vertex> path;
for (auto cursor = goal;;) {
path.push_front(cursor);
auto previous = std::exchange(cursor, predecessors.at(cursor));
if (cursor == previous)
break;
}
fmt::print("{} -> {}: {}\n", start, goal, path);
}
}
哪些印刷品例如。
2 -> 1: [2, 1]
如果您想封装,请沿着功能边界进行,而不是人为的边界,因为它会让您一生都头疼,而不是您不需要的。如果性能无关紧要,您可以使用vector_property_map
之类的工具来减少代码。例如:
住在科里鲁
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/astar_search.hpp>
#include <boost/graph/graph_utility.hpp>
#include <boost/graph/random.hpp>
#include <boost/property_map/transform_value_property_map.hpp>
#include <boost/property_map/vector_property_map.hpp>
#include <fmt/ranges.h>
#include <random>
class BoostGraph {
private:
using JointAngles = std::vector<double>;
struct VertexProperties {
JointAngles joint_angles{0, 0, 0};
};
struct EdgeProperties {
double weight = 0;
};
using Graph = boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS,
VertexProperties, EdgeProperties>;
using Vertex = Graph::vertex_descriptor;
public:
BoostGraph() : m_graph(4) {
// TODO read graph
m_graph[0] = VertexProperties{{0, 0, 0}};
m_graph[1] = VertexProperties{{1, 1, 1}};
m_graph[2] = VertexProperties{{2, 2, 2}};
add_edge(0, 1, m_graph);
add_edge(1, 2, m_graph);
}
friend std::ostream& operator<<(std::ostream& os, BoostGraph const& bg) {
auto name = boost::make_transform_value_property_map(
[ja = get(&VertexProperties::joint_angles, bg.m_graph)](Vertex v) {
return fmt::format("Vertex #{} ({})", v, ja[v]);
},
get(boost::vertex_index, bg.m_graph));
print_graph(bg.m_graph, name, os);
return os;
}
Vertex random_vertex() { return boost::random_vertex(m_graph, m_prng); }
std::list<Vertex> find_path(Vertex start, Vertex goal) const {
std::list<Vertex> path;
auto pmap = make_vector_property_map<Vertex>(get(boost::vertex_index, m_graph));
try {
astar_search( //
m_graph, start, distance_heuristic{goal, m_graph},
boost::predecessor_map(pmap) //
.weight_map(get(&EdgeProperties::weight, m_graph))
.visitor(finder{goal}));
} catch (finder::found) {
for (auto cursor = goal;;) {
path.push_front(cursor);
auto previous = std::exchange(cursor, pmap[cursor]);
if (cursor == previous)
break;
}
}
return path;
}
private:
// visitor that terminates when we find the goal
struct finder : boost::default_astar_visitor {
struct found {}; // exception for termination
Vertex m_goal;
finder(Vertex g) : m_goal(g) {}
void examine_vertex(Vertex u, Graph const&) const {
if (u == m_goal)
throw found{};
}
};
// euclidean distance heuristic
struct distance_heuristic : boost::astar_heuristic<Graph, double> {
distance_heuristic(Vertex goal, Graph const& graph)
: m_graph(graph)
, m_goal(graph[goal].joint_angles) {}
double operator()(Vertex u) const {
auto& c = m_graph[u].joint_angles;
auto //
dx = m_goal.at(0) - c.at(0), //
dy = m_goal.at(1) - c.at(1), //
dz = m_goal.at(2) - c.at(2);
using std::sqrt; // allow ADL, good practice
return sqrt(dx * dx + dy * dy + dz * dz);
}
private:
Graph const& m_graph; // reference!
JointAngles m_goal;
};
Graph m_graph;
std::mt19937 m_prng{std::random_device{}()};
};
int main() {
BoostGraph bg;
std::cout << "Graph: " << bg << "\n";
for (auto i = 0; i < 10; ++i) {
auto start = bg.random_vertex(), goal = bg.random_vertex();
auto path = bg.find_path(start, goal);
fmt::print("{} -> {}: {}\n", start, goal, path);
}
}
打印,例如
Graph: Vertex #0 ([0, 0, 0]) <--> Vertex #1 ([1, 1, 1])
Vertex #1 ([1, 1, 1]) <--> Vertex #0 ([0, 0, 0]) Vertex #2 ([2, 2, 2])
Vertex #2 ([2, 2, 2]) <--> Vertex #1 ([1, 1, 1])
Vertex #3 ([0, 0, 0]) <-->
2 -> 2: [2]
1 -> 0: [1, 0]
0 -> 1: [0, 1]
2 -> 0: [2, 1, 0]
3 -> 0: []
0 -> 3: []
0 -> 3: []
1 -> 0: [1, 0]
1 -> 0: [1, 0]
3 -> 1: []