a vector of subgraphs

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Re: [Boost-users] [serialization]...

fabricio

7 Apr 2009 7 Apr '09

10:59 p.m.

Hello, I'm creating a program that will require a vector, of dynamic size, of subgraphs. so let's suppose I have something like this: typedef subgraph< adjacency_list > Graph; Graph G; what I want is to create a: vector< Graph& > subG; but the usage of & here is illegal. Do you guys have any suggestion on how to do it? regards,

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James C. Sutherland

8 Apr 8 Apr

12:04 a.m.

On Apr 7, 2009, at 4:59 PM, fabricio wrote:

...

typedef subgraph< adjacency_list > Graph;

Graph G;

what I want is to create a:

vector< Graph& > subG;

but the usage of & here is illegal.

Why not use pointers? vector subG; or vector< boost::shared_ptr<Graph> > subG;

fabricio

2:53 a.m.

oh sorry, forgot to mention, after vector< Graph& > subG; I should have something like: subG.resize(2); subG(0) = G.subgraph(); and subgraph() returns a Graph& On 7 abr, 21:04, "James C. Sutherland" wrote:

...

On Apr 7, 2009, at 4:59 PM, fabricio wrote:

...
typedef subgraph< adjacency_list > Graph;

...
Graph G;

...
what I want is to create a:

...
vector< Graph& > subG;

...
but the usage of & here is illegal.

Why not use pointers? vector subG; or vector< boost::shared_ptr<Graph> > subG; _______________________________________________ Boost-users mailing list Boost-us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost-users

Damian Coventry

3:57 a.m.

Agree with James, shared_ptr can help here...

typedef subgraph Graph;
typedef shared_ptr GraphPtr;
typedef vector Graphs;

Graphs graphs;
graphs.push_back(GraphPtr(new Graph));

or perhaps

Graphs graphs;
graphs.resize(2);

graphs[1].reset(new Graph);
graphs[1]->DoStuff();

graphs[0] = GraphPtr(new Graph);
graphs[0]->DoStuff();


~Damian();


> -----Original Message-----
> From: boost-users-bounces@lists.boost.org [mailto:boost-users-
> bounces@lists.boost.org] On Behalf Of fabricio
> Sent: Wednesday, 8 April 2009 2:54 p.m.
> To: boost-users@lists.boost.org
> Subject: Re: [Boost-users] a vector of subgraphs
> 
> oh sorry, forgot to mention, after
> 
> vector< Graph& > subG;
> 
> I should have something like:
> 
> subG.resize(2);
> subG(0) = G.subgraph();
> 
> and subgraph() returns a Graph&
> 
> On 7 abr, 21:04, "James C. Sutherland" 
> wrote:
> > On Apr 7, 2009, at 4:59 PM, fabricio wrote:
> >
> >
> >
> > > typedef subgraph< adjacency_list > Graph;
> >
> > > Graph G;
> >
> > > what I want is to create a:
> >
> > > vector< Graph& > subG;
> >
> > > but the usage of & here is illegal.
> >
> > Why not use pointers?
> >         vector subG;
> > or
> >         vector< boost::shared_ptr > subG;
> > _______________________________________________
> > Boost-users mailing list
> > Boost-
> us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost-
> users
> _______________________________________________
> Boost-users mailing list
> Boost-users@lists.boost.org
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
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fabricio

2:53 p.m.

Ok, but it still won't work for me. Let me rephrase my problem: I have a certain Graph g and I must create several subgraphs from it. In order to create a subgraph I must declare: typedef subgraph Graph; Graph g; and to create the proper subgraphs from g it must be done: Graph& g1 = g.subgraph(); where the subgraph method returns a Graph&. The problem is that I must have "n" different subgraphs and I must have a way to iterate through them. So ideally I should have: vector< Graph& > subg; subg.resize(n); for (i=0;i wrote:

...

Agree with James, shared_ptr can help here...

typedef subgraph Graph; typedef shared_ptr<Graph> GraphPtr; typedef vector<GraphPtr> Graphs;

Graphs graphs; graphs.push_back(GraphPtr(new Graph));

or perhaps

Graphs graphs; graphs.resize(2);

graphs[1].reset(new Graph); graphs[1]->DoStuff();

graphs[0] = GraphPtr(new Graph); graphs[0]->DoStuff();

~Damian();

...
-----Original Message----- From: boost-users-boun...@lists.boost.org [mailto:boost-users- boun...@lists.boost.org] On Behalf Of fabricio Sent: Wednesday, 8 April 2009 2:54 p.m. To: boost-us...@lists.boost.org Subject: Re: [Boost-users] a vector of subgraphs

...
oh sorry, forgot to mention, after

...
vector< Graph& > subG;

...
I should have something like:

...
subG.resize(2); subG(0) = G.subgraph();

...
and subgraph() returns a Graph&

...
On 7 abr, 21:04, "James C. Sutherland" wrote:

...
On Apr 7, 2009, at 4:59 PM, fabricio wrote:

...
...
...
typedef subgraph< adjacency_list > Graph;

...
...
...
Graph G;

...
...
...
what I want is to create a:

...
...
...
vector< Graph& > subG;

...
...
...
but the usage of & here is illegal.

...
...
Why not use pointers? vector subG; or vector< boost::shared_ptr<Graph> > subG; _______________________________________________ Boost-users mailing list Boost- us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost- users

Boost-users mailing list Boost-us...@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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James C. Sutherland

5:19 p.m.

Pointers should still work. See below. You cannot (currently) hold references in containers. I think that this is slated to change in the new c++ standard, but don't know much about that... On Apr 8, 2009, at 8:53 AM, fabricio wrote:

...

Ok, but it still won't work for me.

Let me rephrase my problem:

I have a certain Graph g and I must create several subgraphs from it. In order to create a subgraph I must declare:

typedef subgraph Graph; Graph g;

and to create the proper subgraphs from g it must be done:

Graph& g1 = g.subgraph();

Graph* g1 = g.subgraph();

...

where the subgraph method returns a Graph&.

The problem is that I must have "n" different subgraphs and I must have a way to iterate through them. So ideally I should have:

vector< Graph& > subg;

vector< Graph* > subg;

...

subg.resize(n); for (i=0;i
I guess the use of the reference is necessary so when I insert an edge on one of the graphs it reflects on every subgraph.

best regards, Fabricio

On 8 abr, 00:57, "Damian Coventry" wrote:

...
Agree with James, shared_ptr can help here...

typedef subgraph Graph; typedef shared_ptr<Graph> GraphPtr; typedef vector<GraphPtr> Graphs;

Graphs graphs; graphs.push_back(GraphPtr(new Graph));

or perhaps

Graphs graphs; graphs.resize(2);

graphs[1].reset(new Graph); graphs[1]->DoStuff();

graphs[0] = GraphPtr(new Graph); graphs[0]->DoStuff();

~Damian();

...
-----Original Message----- From: boost-users-boun...@lists.boost.org [mailto:boost-users- boun...@lists.boost.org] On Behalf Of fabricio Sent: Wednesday, 8 April 2009 2:54 p.m. To: boost-us...@lists.boost.org Subject: Re: [Boost-users] a vector of subgraphs

...
oh sorry, forgot to mention, after

...
vector< Graph& > subG;

...
I should have something like:

...
subG.resize(2); subG(0) = G.subgraph();

...
and subgraph() returns a Graph&

...
On 7 abr, 21:04, "James C. Sutherland" wrote:

...
On Apr 7, 2009, at 4:59 PM, fabricio wrote:

...
...
...
typedef subgraph< adjacency_list > Graph;

...
...
...
Graph G;

...
...
...
what I want is to create a:

...
...
...
vector< Graph& > subG;

...
...
...
but the usage of & here is illegal.

...
...
Why not use pointers? vector subG; or vector< boost::shared_ptr<Graph> > subG; _______________________________________________ Boost-users mailing list Boost- us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost- users

Boost-users mailing list Boost-us...@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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fabricio

5:43 p.m.

Hi, thanks for the answers, but using Graph* does not work, it is an invalid cast from Graph& to Graph* the Visual C++ gives me a C2440 error (type cast error) when I try to make Graph* g1 = g.subgraph(); even doing Graph* g1 = (Graph*) g.subgraph(); On 8 abr, 14:19, "James C. Sutherland" wrote:

...

Pointers should still work. See below. You cannot (currently) hold references in containers. I think that this is slated to change in the new c++ standard, but don't know much about that...

On Apr 8, 2009, at 8:53 AM, fabricio wrote:

...
Ok, but it still won't work for me.

...
Let me rephrase my problem:

...
I have a certain Graph g and I must create several subgraphs from it. In order to create a subgraph I must declare:

...
typedef subgraph Graph; Graph g;

...
and to create the proper subgraphs from g it must be done:

...
Graph& g1 = g.subgraph();

Graph* g1 = g.subgraph();

...
where the subgraph method returns a Graph&.

...
The problem is that I must have "n" different subgraphs and I must have a way to iterate through them. So ideally I should have:

...
vector< Graph& > subg;

vector< Graph* > subg;

...
subg.resize(n); for (i=0;i
...
I guess the use of the reference is necessary so when I insert an edge on one of the graphs it reflects on every subgraph.

...
best regards, Fabricio

...
On 8 abr, 00:57, "Damian Coventry" wrote:

...
Agree with James, shared_ptr can help here...

...
...
typedef subgraph Graph; typedef shared_ptr<Graph> GraphPtr; typedef vector<GraphPtr> Graphs;

...
...
Graphs graphs; graphs.push_back(GraphPtr(new Graph));

...
...
or perhaps

...
...
Graphs graphs; graphs.resize(2);

...
...
graphs[1].reset(new Graph); graphs[1]->DoStuff();

...
...
graphs[0] = GraphPtr(new Graph); graphs[0]->DoStuff();

...
...
~Damian();

...
...
...
-----Original Message----- From: boost-users-boun...@lists.boost.org [mailto:boost-users- boun...@lists.boost.org] On Behalf Of fabricio Sent: Wednesday, 8 April 2009 2:54 p.m. To: boost-us...@lists.boost.org Subject: Re: [Boost-users] a vector of subgraphs

...
...
...
oh sorry, forgot to mention, after

...
...
...
vector< Graph& > subG;

...
...
...
I should have something like:

...
...
...
subG.resize(2); subG(0) = G.subgraph();

...
...
...
and subgraph() returns a Graph&

...
...
...
On 7 abr, 21:04, "James C. Sutherland" wrote:

...
On Apr 7, 2009, at 4:59 PM, fabricio wrote:

...
...
...
...
...
typedef subgraph< adjacency_list > Graph;

...
...
...
...
...
Graph G;

...
...
...
...
...
what I want is to create a:

...
...
...
...
...
vector< Graph& > subG;

...
...
...
...
...
but the usage of & here is illegal.

...
...
...
...
Why not use pointers? vector subG; or vector< boost::shared_ptr<Graph> > subG; _______________________________________________ Boost-users mailing list Boost- us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost- users

Boost-users mailing list Boost-us...@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

...
...
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Thomas Klimpel

5:55 p.m.

fabricio wrote:

...

Hi, thanks for the answers, but using Graph* does not work, it is an invalid cast from Graph& to Graph* the Visual C++ gives me a C2440 error (type cast error) when I try to make Graph* g1 = g.subgraph();

Of course you should write Graph* g1 = &g.subgraph(); Regards, Thomas

fabricio

6:13 p.m.

oh how dumb of me, it solved my problem :) thank you everyone On 8 abr, 14:55, Thomas Klimpel wrote:

...

fabricio wrote:

...
Hi, thanks for the answers, but using Graph* does not work, it is an invalid cast from Graph& to Graph* the Visual C++ gives me a C2440 error (type cast error) when I try to make Graph* g1 = g.subgraph();

Of course you should write

Graph* g1 = &g.subgraph();

Regards, Thomas _______________________________________________ Boost-users mailing list Boost-us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost-users

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Damian Coventry
fabricio
James C. Sutherland
Thomas Klimpel