Re: [Boost-users] newbie - graph library - vertex properties

Subject: Re: [Boost-users] newbie - graph library - vertex properties
From: Suresh Kumar (suresh.amritapuri_at_[hidden])
Date: 2009-12-16 19:09:22

Hi Tobias,

Can you just show, how to access the vertex properties using the get()
 function?. I know that map[vertex_descriptior] gives me the
vertex_properties of that particular vertex. But I am unable to figure
out how to use the get function for single vertex property as well as
for the vertex_bundle,

Thanks
suresh

On Tue, Dec 15, 2009 at 3:18 PM, Tobias Columbus <t.columbus_at_[hidden]> wrote:
> Hi again,
>
> Try the following code, which just compiles fine with g++ 4.4.1 on my
> system:
>
> struct City{...};
> struct Highway{...};
>
> typedef ... Map;
>
> int main(){
> Map map;
> Map::vertex_descriptor v = add_vertex( map );
> Map::vertex_descriptor u = add_vertex( map );
> map[v].name = "Troy";
> map[v].population = 49170;
> map[v].zipcodes.push_back(12180);
> Map::edge_descriptor e = add_edge( u, v, map ).first;
> map[e].name = "I-87";
> map[e].miles = 10;
> map[e].speed_limit = 65;
> map[e].lanes = 4;
> map[e].divided = true;
> return 0;
> }
>
> Generally I would suggest reading
> http://www.boost.org/doc/libs/1_41_0/libs/graph/doc/quick_tour.html
> which gives a quick overview of how to handle graphs in BGL.
>
> If you work through this tutorial, vertex and edge properties will also
> get explained.
>
> Regards
> Tobias
>
> On Tuesday 15 December 2009 05:00:01 pm List User wrote:
>> Hi Tobias Columbus,
>>
>> In fact I had tried that also. But then I got a funny message while
> executing like this: Ubuntu 9.04, g++ 4.3.3
>> //Map::vertex_descriptor v = *vertices(map).first;
>>  Map::vertex_descriptor v = add_vertex(map);
>>
>> suresh_at_suresh-laptop:~/C++$ ./a.out
>> *** glibc detected *** ./a.out: free(): invalid pointer: 0x09f9c064
> ***
>> ======= Backtrace: =========
>> /lib/tls/i686/cmov/libc.so.6[0xb7e6a604]
>> /lib/tls/i686/cmov/libc.so.6(cfree+0x96)[0xb7e6c5b6]
>> /usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0xb804d231]
>> ../a.out[0x8049e7d]
>> ../a.out[0x8049ea7]
>> ..
>> ..
>> ..
>>
>> so what to do next?
>>
>> suresh
>>
>>
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-- 
R. Suresh Kumar
PhD Student, Vislab
#216, Engineering II Bldg
University of California, Riverside,
CA 92521