在boost图库中 remove_edge
的函数调用有一个非常奇怪的问题 .
当我在main函数中调用它时,编译和运行时都可以;但是当我在模板函数 test_remove_edge
中调用它时,我得到编译错误 .
代码示例和编译错误消息在这里 .
#include <iostream>
#include <vector>
#include <string>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/max_cardinality_matching.hpp>
#include <boost/graph/maximum_weighted_matching.hpp>
using namespace boost;
template <typename Graph>
void test_remove_edge(const Graph& g)
{
typedef typename graph_traits<Graph>::edge_iterator edge_iterator_t;
edge_iterator_t ei, ei_end;
for (boost::tie(ei,ei_end) = edges(g); ei != ei_end; ++ei)
{
std::cout << typeid(*ei).name() << ", " << typeid(g).name() << std::endl; // exactly same with the one in main
remove_edge(*ei, g); // compile error, see message pasted below
}
}
int main(int argc, const char * argv[])
{
typedef property<edge_weight_t, float, property<edge_index_t, int>> EdgeProperty;
typedef adjacency_list<vecS, vecS, undirectedS, no_property, EdgeProperty> my_graph;
const int n_vertices = 8;
my_graph g(n_vertices);
add_edge(1,2,EdgeProperty(5),g);
add_edge(0,4,EdgeProperty(1),g);
add_edge(1,5,EdgeProperty(4),g);
add_edge(2,6,EdgeProperty(1),g);
add_edge(3,7,EdgeProperty(4),g);
typedef typename graph_traits<my_graph>::edge_iterator edge_iterator_t;
edge_iterator_t ei, ei_end;
for (boost::tie(ei,ei_end) = edges(g); ei != ei_end; ++ei)
{
std::cout << typeid(*ei).name() << ", " << typeid(g).name() << std::endl; // exactly same with the one in test_remove_edge
remove_edge(*ei, g); // compile ok, runtime ok
}
test_remove_edge(g);
return 0;
}
编译错误消息:
忽略候选模板:推断类型'undirected_graph_helper>,boost :: no_property,boost :: listS>,boost :: vecS,boost :: vecS,boost :: undirectedS,boost :: no_property,boost :: property>,boost: :no_property,boost :: listS> :: config>&'的第二个参数与调整后的类型'const boost :: adjacency_list>,boost :: no_property,boost :: listS>'的参数不匹配[with EdgeOrIter = boost :: detail :: edge_desc_impl,Config = boost :: detail :: adj_list_gen>,boost :: no_property,boost :: listS>,boost :: vecS,boost :: vecS,boost :: undirectedS,boost :: no_property,boost :: property>,boost :: no_property,boost :: listS> :: config]
我确信编译器会为两种情况选择相同的重载函数 remove_edge
(Xcode告诉我) . 另外我知道通过检查typeid(T).name()的输出,在调用 remove_edge
时参数类型是相同的 .
感到绝望,非常感谢任何帮助!
1 回答
remove_edge
修改图形,因此无法在const-reference上调用它 . 最简单的修复: