Re: [boost] [Graph] component_index crash on big graph

Subject: Re: [boost] [Graph] component_index crash on big graph
From: Sandeep Gupta (gupta.sandeep_at_[hidden])
Date: 2009-07-07 10:18:16

On Tue, Jul 7, 2009 at 4:40 AM, Andrew Sutton <andrew.n.sutton_at_[hidden]>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
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