you might try to find a combinatorial invariant distinguishing graphs here,
e.g. the 4-vertex condition
(introduced in http://www.ams.org/mathscinet-getitem?mr=340088
more references
here: http://link.springer.com/article/10.1007/s10801-014-0554-1)
On Thursday, November 3, 2016 at 12:13:52 PM UTC, Paul Leopardi wrote:
>
>
>
> On Thursday, 3 November 2016 04:58:11 UTC+11, Dima Pasechnik wrote:
>>
>> On Wednesday, November 2, 2016 at 11:57:20 AM UTC, Paul Leopardi wrote:
>>>
>>> On Wednesday, 2 November 2016 20:08:20 UTC+11, Dima Pasechnik wrote:
>>>>
>>>> I must say I don't know why these libgap.set_global and get_global are
>>>> needed.
>>>>
>>>>>
>>> I used them to get my large matrices into libgap as globals. Trying to
>>> pass them through a text based interface does not work.
>>>
>>
>> ld you show an example of this?
>> IMHO you might indeed have a problem if you use libgap.eval(). But you
>> should not...
>> The other thought is that you appear to work with Cayley graphs, and for
>> them you only need to pass one row of the adjacency matrix,
>> and the group; passing the whole matrix is an overkill.
>>
>>
> Hi Dima,
> Thanks for your patience and for all your help. I finally got the
> following to work:
>
>
> gap.load_package('grape')
>
>
> def check_graphs_using_gap(g_0, g_1):
> m_0 = g_0.adjacency_matrix()
> m_1 = g_1.adjacency_matrix()
> dim = str(m_0.dimensions()[0])
> gap.eval('M_0 := '+gap(m_0).str())
> gap.eval('M_1 := '+gap(m_1).str())
> gap.eval('GR := Group( () )')
> gap.eval('G_0 := Graph( GR, [1..'+dim+'], OnPoints, function(x,y)
> return M_0[x][y] = 1; end,true );')
> gap.eval('G_1 := Graph( GR, [1..'+dim+'], OnPoints, function(x,y)
> return M_1[x][y] = 1; end,true );')
> return gap.eval('IsIsomorphicGraph(G_0, G_1);')
>
> Assuming that the algorithm used is Nauty rather than Bliss, running this
> code against my graphs confirms the cases of non-isomorphism that I
> previously identified.
>
>
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