Re: BGL - how to find end of predecessor chain?

From: Daryle Walker (darylew_at_[hidden])
Date: 2000-10-17 13:50:08

on 10/15/00 1:19 PM, jsiek_at_[hidden] wrote:

> In the case when using an adjacency_list with VertexList=vecS, you could
> initialize the predecessor array to -1.
> 
> In the case when using an adjacency_list with VertexList=listS, you could
> initialize the predecessor array to 0 (null pointer).

I haven't used the graphing library, but I wonder if this
invalid-predecessor tip is documented anywhere?  It could also be a
compile-time traits constant to make generic graph processing easier.

> John Britton writes:
>> After performing a BFS which fills in a vector of Vertex predecessors, how do
>> I determine whether a given Vertex has a valid predecessor? Comparing against
>> a default constructed Vertex doesn't seem to work since the default
>> constructed Vertex apparently has an index of 0, and thus cannot be
>> differentiated from vertex( 0, G ).

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