Re: [Boost-users] [PropertyMap, Graph] Question on constructing a property map from a Cartesian product AxB of two sets to the set C of all real numbers

Subject: Re: [Boost-users] [PropertyMap, Graph] Question on constructing a property map from a Cartesian product AxB of two sets to the set C of all real numbers
From: Jeremiah Willcock (jewillco_at_[hidden])
Date: 2012-06-13 14:10:48

On Tue, 12 Jun 2012, Alex Sadovsky wrote:

> Hello,
> 
> I have defined a directed graph type, and a path type (each variable of 
> type "path" is a sequence (vector) of vertices in the graph such that 
> every two consecutive ones are connected by an edge).  Each path is 
> parameterized by arc length.
> 
> What I'd like to do is tabulate the function that, for each pair 
> (vertex, path) tells the arc length coordinate of the vertex.  I don't 
> want to make it a function: a pair (vertex, path) is likely to come up 
> more than once, and I want to avoid repeating the computation of the arc 
> length coordinate.  Just compute it once and store it in a property map.

Where are you storing the paths?  Are they attached to vertices?  They 
don't appear to be from the definitions below.  Are you going to be using 
all of the <vertex, path> pairs' arc length values?  I don't think I fully 
understand what you're asking---why do you want to store your data in a 
property map?  What are you thinking of as the keys of the property map? 
Vertices, or <vertex, path> pairs, or something else?

-- Jeremiah Willcock