我正在尝试实现自己的A星算法 . 但是,我只想通过迭代器获得边缘权重值 . 由于迭代器按顺序访问属性映射,我不能优先考虑边缘,需要为每个顶点做一个完整的循环以找到邻居,这会使算法真的变慢 .
有没有办法使用get(),put()...没有迭代器,选择我要检查边缘的顶点?
这是我目前的计划:
struct Point {//struct point with vertex properties
int x, y;
int parentx, parenty;
double g;
double h;
friend std::ostream& operator<<(std::ostream& os, Point p) {
return os << "[" << p.x << "," << p.y << "]";
}
};
int main() {
//declarations
typedef property < edge_weight_t, double >Weight;
using std::vector;//?
using Graph = adjacency_list<setS, vecS, undirectedS, Point, Weight>;//graph includes our created point struct property<edge_weight_t
using vertex_descriptor = Graph::vertex_descriptor;
Graph lattuce;
//lattuce graph is created with weighted edges value 1 or 1,41 if diagonal. The functions used on a loop are:
//add_edge(nodes[p.x][p.y],nodes[neighbour.x][neighbour.y], Weight(1.0), lattuce);
//add_edge(nodes[p.x][p.y],nodes[neighbour.x][neighbour.y], Weight(1.4), lattuce);
typedef Graph::edge_iterator EdgeIterator;
std::pair<EdgeIterator, EdgeIterator> edges = boost::edges(lattuce);
typedef boost::property_map<Graph, boost::edge_weight_t>::type WeightMap;
WeightMap weights = boost::get(boost::edge_weight_t(), lattuce);
//cout<<get(weights,(1,2));
EdgeIterator edge;
for (edge = edges.first; edge != edges.second; ++edge) {
std::cout << boost::get(weights, *edge) <<" "<< *edge<< " ";
if (source(*edge, lattuce) == origin || target(*edge, lattuce)==origin ){
get(weights, *edge);
cout<<"Edge related to the origin ";
}
if (source(*edge, lattuce) == end_vertex || target(*edge, lattuce)==end_vertex ){
cout<<"Edge related to the end_vertex ";
}
if (get(weights, *edge)==1.41){
cout<<" Diagonal"<<endl;
}
else if (get(weights, *edge)==1){
cout<<" Unitary"<<endl;
}
else if (get(weights, *edge)==99999999.0){
cout<<"Infinite"<<endl;
}
}
}
此外,希望能够在Point结构中修改f,h和parent的值 .
任何帮助或指导将不胜感激 .
1 回答
回答你的问题
您可以使用顶点描述符而不是迭代器 .
在您的情况下,因为您使用的是捆绑属性,所以可以在图表上使用
operator[descriptor]
简写 .只要图形不是常量,就可以使用它来更改捆绑的属性 .
代码
实际上我不清楚你的问题中的代码应该说明什么 . 我将简单地回复一段代码,这些代码是从那里构建的,并向您展示了一些可能具有启发性的东西:)
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