Different out edge iterators was the problem for my filtered graph example.

It's spelled "compliment" in filtered_graph.hpp lines 507-516.  I guess that's a bug.

Here's a working subset_compliment_filter example.  I did my own graph printing rather than using print_graph(...) in graph_utility.hpp because it seemed easier than defining an vertex property for an implicit graph.


//          Copyright W.P. McNeill 2010.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)

#include <iostream>
#include <boost/graph/grid_graph.hpp>
#include <boost/graph/filtered_graph.hpp>
#include <set>


using namespace boost;

#define RANK 2
typedef grid_graph<RANK> Grid;
typedef graph_traits<Grid>::vertices_size_type vertices_size_type;
typedef graph_traits<Grid>::vertex_descriptor vertex_descriptor;
typedef graph_traits<Grid>::edge_descriptor edge_descriptor;

typedef std::set<vertex_descriptor> VertexSet;
typedef vertex_subset_compliment_filter<Grid, VertexSet>::type
        VertexFilteredGrid;

// Print vertices as (x, y).
std::ostream& operator<<(std::ostream& output, const vertex_descriptor& u) {
  return output << "(" << u[0] << ", " << u[1] << ")";
}

// Print edges as (x1, y1) -> (x2, y2).
std::ostream& operator<<(std::ostream& output, const edge_descriptor& e) {
  return output << e.first << "->" << e.second;
}

// Print all the graph vertices along with their out edges.
template<typename Graph, typename VertexIter, typename EdgeIter>
void print_graph(const Graph &g) {
  VertexIter vi, vi_end;
  for (tie(vi, vi_end) = vertices(g); vi != vi_end; vi++) {
    vertex_descriptor u = *vi;
    std::cout << u << std::endl;
    EdgeIter ei, ei_end;
    for (tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ei++)
      std::cout << "\t" << *ei << std::endl;
  }
}

int main(int argc, char* argv[]) {
  array<std::size_t, RANK> lengths = { {2, 2} };
  Grid g(lengths);

  std::cout << "Original:" << std::endl;
  print_graph<Grid,
              graph_traits<Grid>::vertex_iterator,
              graph_traits<Grid>::out_edge_iterator>(g);

  // Filter the lower right-hand vertex out of the graph.
  vertex_descriptor u = vertex(num_vertices(g)-1, g);
  VertexSet omit;
  omit.insert(u);
  VertexFilteredGrid fg = make_vertex_subset_compliment_filter(g, omit);

  std::cout  << std::endl << "With vertex " << u << " removed:" << std::endl;
  print_graph<VertexFilteredGrid,
              graph_traits<VertexFilteredGrid>::vertex_iterator,
              graph_traits<VertexFilteredGrid>::out_edge_iterator>(fg);

  return 0;
}



On Tue, Jul 13, 2010 at 8:55 AM, Jeremiah Willcock <jewillco@osl.iu.edu> wrote:
On Mon, 12 Jul 2010, W.P. McNeill wrote:

I would put a warning about not subclassing BGL components on the Boost Graph Concepts page since this is a point in the documentation that gives an
overview of the way all the graph concepts are implemented.  It is also a page that I personally kept referring back to.  I guess the warning should mention
that this prohibition is an STL thing, and not specific to BGL.

OK.


I'll take a look at Boost.Program_options, Boost.Lexical_cast, and Boost.Random.

That's up to you -- I don't mind if you use the C functions for those things.


Putting filtered_graph over a grid_graph does seem like the right way to go.  However, I'm having problems doing this.  I can create a filtered version of a
grid graph, however I get build errors when I try to call graph concept functions on it.  Here's a simple example:


#include <iostream>
#include <boost/graph/grid_graph.hpp>
#include <boost/graph/filtered_graph.hpp>
#include <set>

using namespace boost;

#define RANK 2
typedef grid_graph<RANK> Graph;
typedef graph_traits<Graph>::vertex_descriptor vertex_descriptor;
typedef graph_traits<Graph>::edge_descriptor edge_descriptor;
typedef graph_traits<Graph>::out_edge_iterator out_edge_iterator;

// Print vertices as (x, y).
std::ostream& operator<<(std::ostream& output, const vertex_descriptor& u) {
  return output << "(" << u[0] << ", " << u[1] << ")";
}

// Print edges as (x1, y1) -> (x2, y2).
std::ostream& operator<<(std::ostream& output, const edge_descriptor& e) {
  return output << e.first << "->" << e.second;
}

typedef std::set<vertex_descriptor> VertexSet;
typedef vertex_subset_compliment_filter<Graph, VertexSet>::type
        VertexFilteredGraph;


int main(int argc, char* argv[]) {
  array<std::size_t, RANK> lengths = { {3, 3} };
  Graph g(lengths);

  VertexSet omit;
  omit.insert(vertex(1, g)); // Filter vertex (1, 0) out of the graph.
  VertexFilteredGraph fg = make_vertex_subset_compliment_filter(g, omit);

"complement"?



  // Print the out edges coming from (0, 0) in the unfiltered and filtered
  // graphs.
  vertex_descriptor u = vertex(0, g);

  std::cout << "Unfiltered out edges from " << u << std::endl;
  out_edge_iterator oi, oi_end;
  for (tie(oi, oi_end) = out_edges(u, g); oi != oi_end; oi++)
    std::cout << *oi << std::endl;

  std::cout << "Filtered out edges from " << u << std::endl;
  for (tie(oi, oi_end) = out_edges(u, fg); oi != oi_end; oi++)
    std::cout << *oi << std::endl;

fg will have a different out_edge_iterator type than g does, since fg's iterator will need to do the filtering.  I think that is the cause of the errors you are getting.


  return 0;
}

-- Jeremiah Willcock
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