On Feb 28, 2006, at 4:28 AM, Gavin Band wrote:

Dear boosters, I am trying to compile a program which is identical to the example

http://www.boost.org/libs/graph/example/connected_components.cpp

given in the docs, except that in the graph typedef I changed undirectedS to directedS. However, I get a compilation error:

g++ -o test_c++.o -I/usr/include/boost -c test_c++.cpp /usr/include/boost/graph/connected_components.hpp: In function `typename boost::property_traits<IndexMap>::value_type boost::connected_components(const Graph&, ComponentMap) [with Graph = main(int, char**)::Graph, ComponentMap = int*]': test_c++.cpp:45: instantiated from here /usr/include/boost/graph/connected_components.hpp:87: error: incomplete type `boost::STATIC_ASSERTION_FAILURE< false>' used in nested name specifier /usr/include/boost/graph/connected_components.hpp:87: error: size of array has non-integral type `<type error>'

Presumably this is some meta-program's way of telling me that my graph isn't undirected.

Yes, that's what it's doing. connected_components() only works on undirected graphs.

Is there any way to make this work for an directed graph?

You can use the facilities for incremental connected components. Those will work on an undirected graph. In truth, our connected_components() should be modified to decide between the DFS-based algorithm for undirected graphs and the incremental algorithm for directed graphs. Doug