Re: [igraph] neighbors

[Gábor Csárdi]

Hi,

On Tue, Nov 2, 2010 at 4:52 AM, harun pirim <address@hidden> wrote:
> Hi All,
>
> I see an interesting problem using neighbors() function. I have an undirected 
> graph g2 with 90 vertices.
>
> Here is how neighbors() works:
>
> neighbors(g2,2)
>  [1]  0  2  2 14 32 42 64 68 69 71 72 74 96
>
>
> neighbors(g2,3)
>  [1]  3  3  5  8 12 19 20 22 23 26 29 30 41 45 53 57 77 78 79 80 81 82 83 84 
> 85 86 87
> [28] 88 89 90 92 93 94 95
>
>
> neighbors(g2,4)
>  [1]  4  4  6 10 13 14 15 16 17 18 24 25 27 34 35 39 46 47 48 50 54 55 56 59 
> 60 66 68
> [28] 70 71 72 74
>
> Basicly, output includes the node itself. and twice. Do you have any idea why 
> it does so?

Because you have loop edges in your graph. For a single 'v-v' loop
edge 'v' appears twice in the output of neighbors, for consistency.
(Otherwise the degree of the vertex would not match the length of the
neighbors() vector.)

Gabor

> Thank you,
>
>
> Harun Pirim
> _______________________________________________
> igraph-help mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/igraph-help
>



-- 
Gabor Csardi <address@hidden>     UNIL DGM