Dear Group, when computing the connected components of a BGL graph one has to create a vector that holds the component integer assigned to each vertex (See http://www.boost.org/libs/graph/example/connected_components.cpp and http://www.boost.org/libs/graph/doc/connected_components.html). OK, that works very well. But how can I get the component number of each vertex? If my graph has internal properties, I can not simply access the vector with an iterator on the graph vertices: component[*vi]; //doesn't work! This doesn't work, because the vertices (to be specific: the vertex desriptors) of the graph aren't integers if the graph has internal properties. Any idea how to get the component of each vertex? all the best Martin -- ----------------------------------------------------------------------------- Martin Okrslar MPI for Molecular Genetics phone: ++ 49 + 30 / 8413-1166 Computational Molecular Biology Fax: ++ 49 + 30 / 8413-1152 Ihnestrasse 73 email: okrslar@molgen.mpg.de D-14195 Berlin URL: http://cmb.molgen.mpg.de -----------------------------------------------------------------------------