Is it possible to have several edge weight property maps for one graph?

Question

How would I create a graph such that the property map (edge ​​weight) is different in each property map? Is it possible to create such a real estate card? How is an array of property maps?

I have not seen anyone on the Internet using it, can I give an example?

Graph g(10); // graph with 10 nodes cin>>a>>b>>weight1>>weight2>>weight3>>weight4; 

and put each weight on the property map.

Answer 1

You can map properties in various ways. The simplest approach might look something like this:

Using C ++ 11 lambdas with function_property_map

Live on coliru

 #include <boost/property_map/function_property_map.hpp> #include <iostream> struct weights_t { float weight1, weight2, weight3, weight4; }; using namespace boost; int main() { std::vector<weights_t> weight_data { // index is vertex id { 1,2,3,4 }, { 5,6,7,8 }, { 9,10,11,12 }, { 13,14,15,16 }, }; auto wmap1 = make_function_property_map<unsigned, float>([&weight_data](unsigned vertex_id) { return weight_data.at(vertex_id).weight1; }); auto wmap2 = make_function_property_map<unsigned, float>([&weight_data](unsigned vertex_id) { return weight_data.at(vertex_id).weight2; }); auto wmap3 = make_function_property_map<unsigned, float>([&weight_data](unsigned vertex_id) { return weight_data.at(vertex_id).weight3; }); auto wmap4 = make_function_property_map<unsigned, float>([&weight_data](unsigned vertex_id) { return weight_data.at(vertex_id).weight4; }); for (unsigned vertex = 0; vertex < weight_data.size(); ++vertex) std::cout << wmap1[vertex] << "\t" << wmap2[vertex] << "\t" << wmap3[vertex] << "\t"<< wmap4[vertex] << "\n"; } 

Using C ++ 03 with transform_value_property_map

This is basically much more verbose:

Live on coliru

 #include <boost/property_map/transform_value_property_map.hpp> #include <iostream> struct weights_t { float weight1, weight2, weight3, weight4; weights_t(float w1, float w2, float w3, float w4) : weight1(w1), weight2(w2), weight3(w3), weight4(w4) { } template <int which> struct access { typedef float result_type; float operator()(weights_t const& w) const { BOOST_STATIC_ASSERT(which >= 1 && which <= 4); switch (which) { case 1: return w.weight1; case 2: return w.weight2; case 3: return w.weight3; case 4: return w.weight4; } } }; }; using namespace boost; int main() { std::vector<weights_t> weight_data; // index is vertex id weight_data.push_back(weights_t(1,2,3,4)); weight_data.push_back(weights_t(5,6,7,8)); weight_data.push_back(weights_t(9,10,11,12)); weight_data.push_back(weights_t(13,14,15,16)); boost::transform_value_property_map<weights_t::access<1>, weights_t*, float> wmap1 = make_transform_value_property_map(weights_t::access<1>(), &weight_data[0]); boost::transform_value_property_map<weights_t::access<2>, weights_t*, float> wmap2 = make_transform_value_property_map(weights_t::access<2>(), &weight_data[0]); boost::transform_value_property_map<weights_t::access<3>, weights_t*, float> wmap3 = make_transform_value_property_map(weights_t::access<3>(), &weight_data[0]); boost::transform_value_property_map<weights_t::access<4>, weights_t*, float> wmap4 = make_transform_value_property_map(weights_t::access<4>(), &weight_data[0]); for (unsigned vertex = 0; vertex < weight_data.size(); ++vertex) std::cout << wmap1[vertex] << "\t" << wmap2[vertex] << "\t" << wmap3[vertex] << "\t"<< wmap4[vertex] << "\n"; } 

Exit

Both pins are output.

 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16