http://www.boost.org/libs/graph/doc/random.html claims that random_vertex and random_edge both have a runtime complexity linear in the number of vertices and edges, respectively. This seems weird. Given a random access iterator and the number of elements, retrieving a random member should be doable in constant time. Is the complexity guarantee here based on the worst case of the lists only being directionally accessible? If yes, does using container class implementing the RandomAccessIterator concept automatically select constant-time versions of these random retrievers? Thanks for your comments. -- martin; (greetings from the heart of the sun.) \____ echo mailto: !#^."<*>"|tr "<*> mailto:" net@madduck invalid/expired pgp subkeys? use subkeys.pgp.net as keyserver! spamtraps: madduck.bogus@madduck.net this product is under strict quality contril with perfect packing and quality when leving the factory.please keep away from damp.high temperature or sun expose.If found any detectives when purchasing. please return the productby airmail to our administration section and inform the time, place.and store of this purchase for our improvement.We shall give you a satisfactory reply.Thanks for your patronage and welcome your comments. -- http://www.engrish.com