在BOOST GRAPH中定义图形后,在构造函数中初始化filtered_graph对象 [英] To initialize a filtered_graph object in constructor after graph is defined in BOOST GRAPH
问题描述
我在boost中初始化filtered_graph中有一个查询。
I have a query in initializing filtered_graph in boost.
这里是我的代码,
// predicate
template <typename TGraph>
struct edge_predicate
{
bool operator()(const typename boost::graph_traits<TGraph>::edge_descriptor& v) const
{
return true //testing purpose
}
};
// class
class A{
typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, Node_Info, Edge_Info > Graph_t;
typedef boost::filtered_graph < Graph_t , edge_predicate > FilteredGraphType_t;
// members
Graph G;
FilteredGraphType_t FG() ; // empty filter graph ???
// constructor for A
template < ..typename list >
A ( ... input iterators list... )
{
fill the graph G with some values passed in constructor argument list.
// predicate
edge_predicate< Graph_t > EPred;
//filtered_graph
FilteredGraphType_t FG( G, EPred); // I am passing on edge predicate.
}
};
// member function:
FilteredGraphType_t& get_filtered_graph()
{
return FG;
}
问题:
FG是A类的成员,G也是A的成员。最初G是空对象,所以是FG我想的,..
FG is a member of class A, and G is also a member of A. Initially G is empty object, so is FG I suppose,..
A,我用我的逻辑(如顶点数,边缘等)填充图G.
现在,我想创建一个过滤器FG (它是A类的成员)在图G(G填充后)。
In constructor of A, I fill Graph G with my logic ( such as number of vertices, edges etc ). Now, I want to create a filter FG (which is member of class A) over graph G (after G is filled).
我想要的原因是,这个过滤的图形作为一个其他类构造函数的引用传递。这迫使我把FG作为类A的成员(我可以在A本身的构造函数中创建过滤器图的新实例,但它不会用于返回对FG的引用。)
The reason I want this is that this filtered graph is passed as a reference to some other class constructor. This forces me to make FG as member of class A. ( I could create new instance of filter graph in constructor of A itself, but it wont serve the purpose of returning the reference to FG. )
我希望很清楚。请建议
推荐答案
您可以让您的代码编译并运行正常。请尝试按如下方式重新组织构造函数:
You can make your code compile and work OK. Try reorganizing the constructor as follows:
// constructor for A
template < ..typename list >
A ( ... input iterators list... )
: G() //calls constructor for G
, EPred(...) //some constructor for predicate
, FG( boost::make_filtered_graph(G, EPred) ) //creates your filtered graph
{
// fill the graph G with some values passed in constructor argument list.
}
其余代码可保持不变。
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