Re: [boost] BGL - Adjusting edge weights via a ucs_visitor

From: Jeremy Siek (jsiek_at_[hidden])
Date: 2001-01-26 16:19:13

Before calling uniform_cost_search(), you could run through all the edges
using the edges(g) function and decide at that point which weights to
use.

Cheers,
Jeremy

On Fri, 26 Jan 2001 aalness_at_[hidden] wrote:

aalnes> 
aalnes> Sorry this was an afterthought to my last email, is there a way to visit
aalnes> all the edges before insertion into the priority queue?
aalnes> 
aalnes> -Andy
aalnes> 
aalnes> On Fri, 26 Jan 2001 aalness_at_[hidden] wrote:
aalnes> 
aalnes> >
aalnes> > Yes I wanted the edge weights to be dynamic in the sense that I wanted to
aalnes> > keep the weights given to me by BGP but also have the option of using a
aalnes> > manually given weight from another source. I thought I could do that
aalnes> > durinvg the search, so I guess the only way is to actually modify the edge
aalnes> > weight before doing the search? Thanks.
aalnes> >
aalnes> > -Andy
aalnes> >
aalnes> > On Fri, 26 Jan 2001, Jeremy Siek wrote:
aalnes> >
aalnes> > > Hi Andy,
aalnes> > >
aalnes> > > I'm not sure I completely understand what you are doing, but a first
aalnes> > > glance one thing strikes be as odd. Are you changing the edge weights
aalnes> > > *during* the search. This will invalidate the shortest-distance properties
aalnes> > > of the search because inside of uniform_cost_search(), vertices are placed
aalnes> > > in a priority queue based on distance (and thereby edge weight). If you
aalnes> > > change edge weights, this priority queue will no longer be accurate.
aalnes> > >
aalnes> >
aalnes> >
aalnes> >
aalnes> >
aalnes> >
aalnes> 
aalnes> -- 
aalnes> ----------------------
aalnes> Andrew Alness
aalnes> Software Engineer
aalnes> Sonicity, Inc.
aalnes> aalness_at_[hidden]
aalnes> 
aalnes> "I want my two dollars." -kid on bike
aalnes> 
aalnes> 
aalnes> 
aalnes> 
aalnes> 
aalnes> 

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 Jeremy Siek                        www: http://www.lsc.nd.edu/~jsiek/
 Ph.D. Candidate                  email: jsiek_at_[hidden]
 Univ. of Notre Dame         work phone: [phone]
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