On Tue, 7 Jul 2009, Sandeep Gupta wrote:
On Tue, Jul 7, 2009 at 4:40 AM, Andrew Sutton <andrew.n.sutton@gmail.com>wrote:
I am using the incremental connected component + component_index to find connected components in an undirected graph. However the program works
fine
on small small dataset but segfaults on large input. I tried to do some debugging and the best I could come up was that it fails on array_push_front cal at the boost/graph/detail/incremental_component.hpp:78.
It doesn't appear as though you have allocated any vertices for the graph. I'm pretty sure that add_edge does not allocate new vertices.
I would guess that every time you call add_vertex, you are referencing data that doesn't actually exist. The successful run may be attributed to a) that the default constructor for the graph (or vector) pre-allocates a small number of elements, or b) pure luck.
Thanks Andrew, I got confused with add_vertex and add_edge allocation properties. I have modified the code create numEdges. However the problem occurs while building component_index which does not access graph data structure but rather only the parent map. Attached is the modified file (also at http://codepad.org/5dZM6YBo).
P.S. The command to run on ManyEdges would now be ./a.out ManyEdges.txt 21174
You appear to be mixing up the vector used as the data for the parent map with the disjoint_set structure. Try using an iterator property map created on the vector (or a shared_array_property_map in newer versions of Boost) as the parent map for the disjoint set structure. -- Jeremiah Willcock