On Wed, Jul 14, 2010 at 5:04 PM, Jeremiah Willcock
<jewillco@osl.iu.edu> wrote:
On Wed, 14 Jul 2010, W.P. McNeill wrote:
On Wed, Jul 14, 2010 at 3:16 PM, Jeremiah Willcock <jewillco@osl.iu.edu> wrote:
On Wed, 14 Jul 2010, W.P. McNeill wrote:
I verified the documentation changes for grid graph indexing calls and A* visitors. Looks good. Now doing edge weights with
a static_property_map<>.
OK.
I've duplicated relevant information from the README at the top of maze.cpp, so README doesn't need to be included in the Boost examples.
I found that I have to implement my own vertex index map, though I'm not sure exactly why. If I remove all my vertex index map code and
call A* with the
default map like so:
astar_search(m_barrier_grid,
source(),
heuristic,
boost::weight_map(weight).
predecessor_map(pred_pmap).
distance_map(dist_pmap).
visitor(visitor) );
I get the following error:
(snip)
That is a bug in astar_search(). Please try with the latest Boost trunk and see if it works. I also added named parameters to
astar_search_no_init().
I tried building with the default index map again against the Boost tree at version 64026 and got the same error as before:
All of this is true when building against revision 64030 of Boost.
graph_traits.hpp:226: error: no type named ‘vertex_property_type’ in ‘class grid’ I noticed that the documentation for the the vertex_index_map parameter says that the graph must have an internal vertex_index property. Could this be the problem? If I try to add the following line to a working build:
typedef grid::vertex_index grid_vertex_index;
I get this error:
g++ -g -I/src/boost-trunk -Wall -Werror -O3 -c -o astar_maze.o astar_maze.cpp
astar_maze.cpp:62: error: ‘vertex_index’ in class ‘grid’ does not name a type
What is supposed to work is:
boost::property_map<grid, boost::vertex_index>::const_type pm
= get(boost::vertex_index, grid());
If that succeeds, it's an algorithm bug most likely.
First, I can't get grid_graph's argumentless constructor to work. The following program does not build.
#include <boost/graph/grid_graph.hpp>
int main (int argc, char const *argv[]) {
boost::grid_graph<2> g = boost::grid_graph<2>();
return 0;
}
g++ -g -I/src/boost-trunk -Wall -Werror -O3 -c -o grid.o grid.cpp
grid.cpp: In function ‘int main(int, const char**)’:
/src/boost-trunk/boost/graph/grid_graph.hpp:232: error: ‘boost::grid_graph<DimensionsT, VertexIndexT, EdgeIndexT>::grid_graph() [with long unsigned int Dimensions = 2ul, VertexIndex = size_t, EdgeIndex = size_t]’ is private
grid.cpp:4: error: within this context
/src/boost-trunk/boost/graph/grid_graph.hpp: In constructor ‘boost::grid_graph<DimensionsT, VertexIndexT, EdgeIndexT>::grid_graph() [with long unsigned int Dimensions = 2ul, VertexIndex = size_t, EdgeIndex = size_t]’:
grid.cpp:4: instantiated from here
/src/boost-trunk/boost/graph/grid_graph.hpp:232: error: uninitialized member ‘boost::grid_graph<2ul, size_t, size_t>::m_dimension_lengths’ with ‘const’ type ‘const boost::array<size_t, 2ul>’
It looks like the grid_graph() constructor at line grid_graph.hpp 232 needs to initialize m_dimension_lengths. (Tricky because you need to use curly braces and assignment.)
The program does build if you change the line to:
boost::grid_graph<2> g();
But that's an aside. In my code can use the m_grid grid graph, which has already been created. If I remove all the vertex index code and the call to astar_search from my program, and add the following line to the maze::solve() function:
boost::property_map<grid, boost::vertex_index_t>::const_type pm = get(boost::vertex_index, m_grid);
The program builds. Does that indicate that it's a problem with astar_search then?
-- Jeremiah Willcock
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