问题
I have a adjacency list of type
boost::adjacency_list<boost::setS, boost::vecS, boost::directedS, GraphData>
Where GraphData is a structure contains name
struct GraphItem
{
std::string Name;
}
I am able to write graph to xml
void WriteGraph() {
boost::dynamic_properties dp;
dp.property("Name", make_transform_value_property_map(&Name,
boost::get(vertex_bundle, graph)));
boost::write_graphml(filename, graph, dp, true);
}
std::string Name(boost::vertex_bundle_type<Graph>::type v) {
std::ostringstream oss;
oss << v.Name;
return oss.str();
}
I get XML as
<graphml>
<key id="key0" for="node" attr.name="Name" attr.type="string" />
<graph id="G" edgedefault="directed" parse.nodeids="canonical"
parse.edgeids="canonical" parse.order="nodesfirst">
<node id="n0">
<data key="key0">A</data>
</node>
<node id="n1">
<data key="key0">D</data>
</node>
<node id="n2">
<data key="key0">B</data>
</node>
<node id="n3">
<data key="key0">C</data>
</node>
<edge id="e0" source="n0" target="n1">
</edge>
<edge id="e1" source="n2" target="n3">
</edge>
</graph>
</graphml>
When I read graph
void ReadGraph() {
boost::dynamic_properties dp;
std::ifstream file(fileName);
boost::read_graphml(file, graph, dp);
}
This is crashing says property Name not found. If I use ignore_other_properties for property,
boost::dynamic_properties dp(ignore_other_properties);
It works but I am not getting any graph item in graph vertices.
回答1:
The graph is not empty, you get:
0 --> 1
1 -->
2 --> 3
3 -->
Or in XML: https://paste.ubuntu.com/p/c4tGmxGssJ/
Of course, you wanted to read the name property. For that you obviously need to register the property with the dynamic-properties map.
Note You can access members of property bundles much simpler:
dp.property("Name", boost::get(&GraphData::Name, graph));
Full Demo
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graphml.hpp>
struct GraphData {
std::string Name;
};
using Graph = boost::adjacency_list<boost::setS, boost::vecS, boost::directedS, GraphData>;
Graph ReadGraph(std::string const& fileName) {
Graph graph;
boost::dynamic_properties dp;
dp.property("Name", boost::get(&GraphData::Name, graph));
std::ifstream file(fileName);
boost::read_graphml(file, graph, dp);
return graph;
}
void WriteGraph(std::ostream& os, Graph& graph) {
boost::dynamic_properties dp;
dp.property("Name", get(&GraphData::Name, graph));
boost::write_graphml(os, graph, dp, true);
}
#include <boost/graph/graph_utility.hpp>
int main() {
Graph g = ReadGraph("input.txt");
print_graph(g, get(&GraphData::Name, g));
// or as XML
WriteGraph(std::cout << "==== XML version: ====\n\n", g);
}
Prints
A --> D
D -->
B --> C
C -->
==== XML version: ====
<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
<key id="key0" for="node" attr.name="Name" attr.type="string" />
<graph id="G" edgedefault="directed" parse.nodeids="canonical" parse.edgeids="canonical" parse.order="nodesfirst">
<node id="n0">
<data key="key0">A</data>
</node>
<node id="n1">
<data key="key0">D</data>
</node>
<node id="n2">
<data key="key0">B</data>
</node>
<node id="n3">
<data key="key0">C</data>
</node>
<edge id="e0" source="n0" target="n1">
</edge>
<edge id="e1" source="n2" target="n3">
</edge>
</graph>
</graphml>
来源:https://stackoverflow.com/questions/49047897/boost-read-graphml-doesnt-read-xml-properly-it-gives-all-the-vertices-but-they