Iterator Property Map Adaptor

Boost , ,

iterator_property_map<RandomAccessIterator, OffsetMap, T, R>

This property map is an adaptor that converts any random access iterator into a Lvalue Property Map. The OffsetMap type is responsible for converting key objects to integers that can be used as offsets with the random access iterator.

Example

// print out the capacity and flow for all the edges in the graph
template <class Graph, class CapacityPMap, class FlowPMap>
void print_network(Graph& G, CapacityPMap capacity, FlowPMap flow)
{
  typedef typename boost::graph_traits<Graph>::vertex_iterator    Viter;
  typedef typename boost::graph_traits<Graph>::out_edge_iterator OutEdgeIter;
  typedef typename boost::graph_traits<Graph>::in_edge_iterator InEdgeIter;
  Viter ui, uiend;
  for (boost::tie(ui, uiend) = vertices(G); ui != uiend; ++ui) {
    OutEdgeIter out, out_end;
    std::cout << *ui << "\t";
    for(boost::tie(out, out_end) = out_edges(*ui, G); out != out_end; ++out)
      std::cout << "--(" << get(capacity, *out) << ", " 
	   << get(flow, *out) << ")--> " << target(*out,G) << "\t";
    std::cout << std::endl << "\t";
    InEdgeIter in, in_end;    
    for(boost::tie(in, in_end) = in_edges(*ui, G); in != in_end; ++in)
      std::cout << "<--(" << get(capacity, *in) << "," << get(flow, *in) << ")-- "
           << source(*in,G) << "\t";
    std::cout << std::endl;
  }
}
int main(int, char*[])
{
  typedef boost::adjacency_list<boost::vecS, boost::vecS, 
    boost::bidirectionalS, boost::no_plugin, 
    boost::plugin<boost::id_tag, std::size_t> > Graph;
  const int num_vertices = 9;
  Graph G(num_vertices);
  int capacity[] = { 10, 20, 20, 20, 40, 40, 20, 20, 20, 10 };
  int flow[] = { 8, 12, 12, 12, 12, 12, 16, 16, 16, 8 };
  // add edges to the graph, and assign each edge an ID number
  // to index into the property arrays
  add_edge(G, 0, 1, 0);
  // ...
  typedef boost::graph_traits<Graph>::edge_descriptor Edge;
  typedef boost::property_map<Graph, boost::id_tag>::type EdgeID_PMap;
  EdgeID_PMap edge_id = get(boost::edge_index(), G);
  boost::iterator_property_map<int*, EdgeID_PMap, int, int&>
     capacity_pa(capacity, edge_id),
     flow_pa(flow, edge_id);
  print_network(G, capacity_pa, flow_pa);
          
  return 0;
}

Where Defined

boost/property_map/property_map.hpp

Model Of

Template Parameters

Members

In addition to the methods and functions required by Lvalue Property Map, this class has the following members.

property_traits<iterator_property_map>::value_type

iterator_property_map(Iterator i)

iterator_property_map(Iterator i, OffsetMap m)

reference operator[](const key_type& v) const

Non-Member functions

  template <class RAIter, class OffsetMap>
  iterator_property_map<RAIter, OffsetMap,
    typename std::iterator_traits<RAIter>::value_type,
    typename std::iterator_traits<RAIter>::reference
    >
  make_iterator_property_map(RAIter iter, OffsetMap omap)

  template <class RAIter, class OffsetMap, class ValueType>
  iterator_property_map<RAIter, OffsetMap,
    typename std::iterator_traits<RAIter>::value_type,
    typename std::iterator_traits<RAIter>::reference
    >
  make_iterator_property_map(RAIter iter, OffsetMap omap, ValueType dummy_arg)

Статья Iterator Property Map Adaptor раздела может быть полезна для разработчиков на c++ и boost.

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