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Subject: Re: [Boost-users] Extending boost graph edge class
From: Rafael Gasperetti (rafaelgasperetti_at_[hidden])
Date: 2016-05-03 18:34:11

The third option fit in my case. I haver a class that I need to be the edge of the graph, and i have another one that I need to be the vertex. Using this way, My classes Can be used inside the graph to calculate distance, scc, etc.

-------- Mensagem original --------
De : Daniel Hofmann <daniel_at_[hidden]>
Data: 03/05/2016 19:23 (GMT-03:00)
Para: boost-users_at_[hidden]
Assunto: Re: [Boost-users] Extending boost graph edge class

Can you elaborate on "extend the edge class"?

Here are some possible interpretations:

1/ You want to optimize the memory consumption for large graphs. The
edges and vertices still fit into uint32_t:

  using graph_t = compressed_sparse_row_graph<directedS,
    no_property, no_property, no_property,
    uint32_t /* Vertex */,
    uint32_t /* EdgeIndex */>;

2/ You want to store arbitrary metadata on your edges and retrieve this
edge data based on your graph and a specific edge descriptor:

  struct edge_data_t { int distance = 0; };

  using graph_t = compressed_sparse_row_graph<directedS,
    no_property, edge_data_t>;

  // ..

  auto duration = [&graph](auto edge) { return graph[edge].duration; };
  auto total = accumulate(edges(graph) | transformed(duration), 0);

This example is using "bundled properties". There is also the
possibility to store edge data external to the graph and not couple the
edge data's lifetime with the graph (e.g. if you need edge weights for a
particular algorithm in your use-case).

3/ You want to provide your own graph representation and make it a model
for the BGL graph concepts:

Here are some more BGL examples that should get you started:

Daniel J H

On 05/03/2016 08:37 AM, Rafael Gasperetti wrote:
> Hi,
> My name is Rafael and I need to extend the edge class of de graph part
> of the boost lib, but I always find problems trying to do this. Can you
> help me with examples and explanations about how to do this?
> I read a lotação of places trying to do this but no help was found,
> please help me.
> Thanks a lot,
> Rafael
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
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