Re: [Boost-users] Trouble w/ fruchterman-reingold

5 Oct 2012


      On Fri, 5 Oct 2012, eric wrote:
...
I changed it to:
property_map::vertex_descriptor,
Topology::point_type> positionMap;
  minstd_rand gen;
  Topology rect_top(gen, -25, -25, 25, 25);
  random_graph_layout(graph, positionMap, rect_top);
so that it would conform w/ the description  here
http://www.boost.org/doc/libs/1_51_0/libs/graph/doc/random_layout.html
that says:
IN/OUT: PositionMap position
The property map that stores the position of each vertex. The type
PositionMap must be a model of Lvalue Property Map such that the vertex
descriptor type of Graph is convertible to its key type. Its value type must
be Topology::point_type, representing the coordinates of the vertex.
Now I get the error message:
1>c:\program files (x86)\boost\boost_1_51\boost\graph\properties.hpp(222) :
error C2039: 'type' : is not a member of 'boost::vertex_property_type<G>'
1>        with
1>        [
1>            G=unsigned int
1>        ]
1>        c:\program files
(x86)\boost\boost_1_51\boost\graph\properties.hpp(233) : see reference to
class template instantiation
'boost::detail::vertex_property_map' being compiled
1>        with
1>        [
1>            Graph=unsigned int,
1>            PropertyTag=boost::rectangle_topology<>::point_type
1>        ]
I think what I really need is a comprehensible example.  All that I've found
in the way of an example is  here
http://www.boost.org/doc/libs/1_42_0/libs/graph/test/layout_test.cpp  .
But it contains so much Boost-specific jargony things that it's not really
good for a beginner to look at and get the sense of how things work.
Do you have any such examples up your sleeve?
Here are the two I see off-hand in the source tree:

- libs/graph/example/fr_layout.cpp

- The test_cube() function in libs/graph/test/layout_test.cpp, ignoring 
everything in the function between the typedef for edge_iterator and the 
line containing "minstd_rand gen;" (in the trunk version at 
URL:https://svn.boost.org/svn/boost/trunk/libs/graph/test/layout_test.cpp, 
look at lines 202-219 in particular).  Just that section should be easier 
to understand.

-- Jeremiah Willcock