Re: [jgrapht-users] DirectedGraph equality testing

[Aidan D. <ai...@on...>]

John,
Thanks a lot for the clarification. Of course I was too wrapped up in what
I was trying to do to consider the multigraph case. I'll modify my approach.

-- 
Aidan Delaney
On Aug 13, 2015 12:56 AM, "John Sichi" <js...@gm...> wrote:

> For multigraphs, e1 and e2 may both have source v1 and target v2, and yet
> they are two distinct edges.
>
> In general, "equality" for a graph isn't a very useful concept due to the
> fact that g1 and g2 may be isomorphic even though !g1.equals(g2).
>
>
> On Wed, Aug 12, 2015 at 2:30 PM, Aidan Delaney <
> ai...@on...> wrote:
>
>> Dear all,
>>         I've been trying to test for deep vertex & edge equality in a
>> DirectedGraph.  An example is below.  It appears that this fails
>> because, I think, DefaultEdge needs a non-default hashCode
>> implementation.  My GitHub pull-request is at [1], but it causes more
>> problems than it solves.
>>
>> Am I just incorrect in trying to use JGraphT in this way to check graph
>> equality?  Is there some other way I should be doing this?
>>
>> DirectedGraph<String, DefaultEdge> g1 =
>>             new SimpleDirectedGraph<String,
>> DefaultEdge>(DefaultEdge.class);
>>         DirectedGraph<String, DefaultEdge> g2 =
>>             new SimpleDirectedGraph<String,
>> DefaultEdge>(DefaultEdge.class);
>>
>>         g1.addVertex("A");
>>         g2.addVertex("A");
>>
>>         assertEquals(g1, g2);
>>
>>         g1.addVertex("B");
>>         g2.addVertex("B");
>>
>>         assertEquals(g1, g2);
>>
>> [1] https://github.com/jgrapht/jgrapht/pull/148
>>
>> --
>> Dr Aidan Delaney
>> Principal Lecturer
>> Computing, Engineering & Maths
>> University of Brighton
>>
>> @aidandelaney
>>
>>
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>
>