Re: [Boost-users] [BGL] resize/reserve on graph?

Subject: Re: [Boost-users] [BGL] resize/reserve on graph?
From: Geoff Hilton (geoff.hilton_at_[hidden])
Date: 2011-08-09 18:59:01

> On Tue, Aug 9, 2011 at 3:13 PM, Geoff Hilton
> <geoff.hilton_at_[hidden] <mailto:geoff.hilton_at_[hidden]>> wrote:
>
>     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