Re: [Boost-users] Default weight map doesn't work for weighted grid graph in A-star search

On Tue, 6 Jul 2010, W.P. McNeill wrote:

I checked out the Boost trunk from http://svn.boost.org/svn/boost/trunk and rebuilt the program below using those headers.  It builds and runs.  From now on unless I say otherwise, everything I do uses this version of Boost. Next I tried to add distance and predecessor maps for the output.  Following the astar-cities.cpp example, I implemented these as vectors.  The program now looks like this:

#include #include #include <iostream> #include <vector>

using namespace boost;

typedef grid_graph<2> grid; typedef graph_traits<grid> traits; typedef traits::vertex_descriptor vertex_descriptor; typedef traits::edge_descriptor edge_descriptor;

typedef double edge_weight_type;

struct zero_heuristic:public   boost::astar_heuristic {

  edge_weight_type operator()(vertex_descriptor v) {     return 0;   } };

int main (int argc, char const *argv[]) {   array sizes = {{ 3, 2 }};   grid g(sizes);   shared_array_property_map::const_type>                             weight(num_edges(g), get(edge_index, g));   std::vector p(num_vertices(g));   std::vector d(num_vertices(g));

  vertex_descriptor start = vertex(0, g);

  astar_search(g,                start,                zero_heuristic(),                weight_map(weight).                predecessor_map(&p[0]).distance_map(&d[0]) );

  return 0; }

It now fails to compile because of what looks like a missing put() functions for the distance and predecessor maps.  The top of the error spew looks contains a distance map error that looks like this:

You need to use iterator_property_map, not just a raw pointer, as your property map (for distance and predecessor maps). You can also use more shared_array_property_maps instead. -- Jeremiah Willcock