Subject: Re: [Boost-users] [BGL] resize/reserve on graph?
From: Geoff Hilton (geoff.hilton_at_[hidden])
Date: 2011-08-09 20:19:50
> On Tue, Aug 9, 2011 at 6:59 PM, Geoff Hilton wrote:
>
> On Tue, Aug 9, 2011 at 3:13 PM, Geoff Hilton
>
> If I know that during the execution of the algorithm the graph size
> must be grown by X number of vertices in one go, is there a way this
> can be done to avoid multiple allocations such as when using
> std::vector's reserve(..) or resize(..) member functions without
> subverting the BGL's documented interface? Currently I use a for
> loop which iterates over add_vertex(vertex_property, graph). Can a
> reserve and/or resize equivalent otherwise please be added somewhere?
>
> Thank you,
> Geoff
>
>
> > On 09/08/2011 6:12 PM, Anil Ramapanicker wrote:
> > I think you are asking about implicit graph where vertices and edges are
> > unknown at the begining and they are added during the execution of an
> > algorithm. You can do it in two ways
> > a) If you are using internal properties then
> > add_vertex( vertex_whatever,g) will work
> > b) If you are using exterior property map then use
> vector_property_map
> > since the size is unknown
> >
> http://www.boost.org/doc/libs/__1_47_0/libs/property_map/doc/__vector_property_map.html
> > Anil
>
> That's exactly what I'm already doing. I'm asking because true, at
> first I do invariably have to use add_vertex(..), but later on I
> know exactly how many vertices by which to grow the graph at a time
> due to the algorithm I'm implementing and I wish to add them in as
> few memory allocations as possible (preferably one) to the existing
> graph. Thus, something like std::vector's resize/reserve or an
> equivalent would be useful.
>
>
> Thank you,
> Geoff
>On 09/08/2011 7:54 PM, Anil Ramapanicker wrote:
> Okay, I think I got what you are saying.You may have to content with
> iteratively adding those vertices.
Possibly, which is why I included the last sentence in my original message.