RE: [boost] Graph: transitive closure interface

From: Fernando Cacciola (fcacciola_at_[hidden])
Date: 2001-09-14 14:09:12

----- Original Message -----
From: Jeremy Siek <jsiek_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Friday, September 14, 2001 1:19 PM
Subject: [boost] Graph: transitive closure interface

>
> For those of you interesting in using the BGL transitive_closure
> function...
>
> Vladimir and I have been discussing two options for the interface
> of transitive_closure:
>
> (1) The 2-graph parameter version
> transitive_closure(G,                      // IN
>                    Gclose,                 // OUT
>                    G_to_Gclose_vertex_map) // UTIL/OUT
>
> or, using a default map:
> transitive_closure(G, Gclose)
>
> (2) The 1-graph parameter version
> transitive_closure(G) // IN-OUT
>
>
>
> Version (1) fills in the initially empty Gclose with the transitive
> closure of G.
>
> Version (2) deletes all the edges in G and then fills it back up again
> with the transitive closure.
>
>
>
> I like version (1) because it is a close match to the mathematical
> abstraction, it uses to graphs, G and Gclose to model the two
> mathematical objects G and G*.
>
> Vladimir likes version (2) because he feels it is easier to use.
>
>
> In terms of space/time efficiency, both versions are similar, though
> version (2) may have a small advantage in terms of space.
>
>
Can I use version 1 as in:
  transitive_closure(G, G)?

If so, I think version 1 is the right one since I can model the behaviour of
version 2 (but not the other way around)

Fernando Cacciola
Sierra s.r.l.
fcacciola_at_[hidden]
www.gosierra.com

> Cheers,
> Jeremy
>
> ----------------------------------------------------------------------
>  Jeremy Siek                          http://php.indiana.edu/~jsiek/
>  Ph.D. Student, Indiana Univ. B'ton   email: jsiek_at_[hidden]
>  C++ Booster (http://www.boost.org)   office phone: [phone]
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