On Thu, Mar 21, 2019 at 3:03 PM Ai Bo <boaisp...@gmail.com> wrote:
> is this "nauty26r7/geng" a program available?
geng is installed in local/bin/ sub-directory of your Sage
installation, as a part of Sage's standard package nauty.
> Also, as Python is slow, any part of the nautygen can be written in other
> language, such as C/C++?
it is written in C, so it's quite fast in this sense.
>
> Thanks,
> Laura
>
> On Wednesday, March 20, 2019 at 11:48:38 PM UTC-7, Jori Mäntysalo (TAU) wrote:
>>
>> On Thu, 21 Mar 2019, Ai Bo wrote:
>>
>> > Is there a way to "random access"? For example, access the nth element
>> > in the "generator", instead of one by one?
>>
>> Kind of. As a most time is propably spent by creating Python data
>> structures for SageMath, you can use nautygen directly to generate huge
>> number of graphs.
>>
>> As an example, it takes below 5 seconds to generate all biconnected graphs
>> on 10 vertices, and I took third last one:
>>
>> $ nauty26r7/geng 10 -C | tail -3 | head -1
>> >A /home/jm58660/lat-koe/nauty26r7/geng -Cd2D9 n=10 e=10-45
>> >Z 9743542 graphs generated in 4.59 sec
>> I]~~~~~~w
>>
>> and now
>>
>> sage: g = Graph('I]~~~~~~w', format='graph6')
>> sage: g.is_biconnected()
>> True
>>
>>
>> --
>> Jori Mäntysalo
>>
>> Tampereen yliopisto - Ihminen ratkaisee
>
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