[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [igraph] Why are unconnected subgraphs not considered by motif count
From: |
Szabolcs Horvát |
Subject: |
Re: [igraph] Why are unconnected subgraphs not considered by motif counting functions? |
Date: |
Thu, 16 Jul 2015 14:24:16 +0200 |
I didn't know about triad_census(). Thanks for the pointer!
On 16 July 2015 at 14:21, Gábor Csárdi <address@hidden> wrote:
> I cannot recall what the actual reason was, but one possible
> explanation is that even for moderately sized graphs, if they are
> sparse, you have a lot of those "motifs", more than what you can count
> in an 'int'.
>
> Btw. triad_census gives you the count for those "motifs" as well, and
> it already overflows for a ring with 10000 vertices and edges:
>
> triad_census(make_ring(10, directed = TRUE))
> #> [1] 50 60 0 0 0 10 0 0 0 0 0 0 0 0 0 0
> triad_census(make_ring(10000, directed = TRUE))
> #> [1] -271196661 99960000 0 0 0 10000
> #> [7] 0 0 0 0 0 0
> #> [13] 0 0 0 0
>
> It does not even warn you, which is pretty bad, actually.....
>
> Gabor
>
> On Thu, Jul 16, 2015 at 3:21 AM, Szabolcs Horvát <address@hidden> wrote:
>> Dear All,
>>
>> igraph's motif counting functions (motifs()) will not count
>> unconnected subgraphs and always return NA for the 1st, 2nd and 4th
>> element of the result (for 3-motifs).
>>
>> The reasoning is that (quoting from the docs):
>>
>>> Note that for unconnected subgraphs, which are not considered to be
>>> motifs, the result will be NA.
>>
>> Is there any _technical_ reason for this behaviour? I understand that
>> according to some definitions, unconnected subgraphs are not
>> considered motifs, but in many applications it is still useful to
>> count _all_ size-k subgraphs.
>>
>> It would be useful if motifs() returned all counts. It is much easier
>> to simply ignore those I don't want (when I don't want them) than
>> having to separately count the missing ones.
>>
>> Szabolcs
>>
>> _______________________________________________
>> igraph-help mailing list
>> address@hidden
>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>
> _______________________________________________
> igraph-help mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/igraph-help