Thank you.
[email protected]
From: Gábor Csárdi
Date: 2014-02-24 22:45
To: Help for igraph users
Subject: Re: [igraph] Error in using the function subcomponent( )
On Mon, Feb 24, 2014 at 9:29 AM, [email protected] <[email protected]>
wrote:
Hi!
Thanks for your kind reply. But I still have two question about the function
subcomponent( ):
1. Should not the result of " subcomponent(g, 4, "all")" be the union of
"subcomponent(g, 4, "in")" and "subcomponent(g, 4, "out")"?
No. Just calculate it by hand for your graph.
2. The graph is a directed network with 10 vertices and 10 edges and the
vertice 0 is an isolated node.
Yes, because vertices are numbered from zero in an 'edgelist' file.
Even if 4 in the source code is 5 in the graph, the result of subcomponent(g,
4, "out") is supposed to be NULL, because there is no vertice could be reached
from vertice 5 in graph.
You need to add one to the numbers in the file, to get the ids in R igraph. So
when you write subcomponent(g, 4, "out") that belongs to vertex 3 in your file.
Which does have an outgoing edge, so subcomponent(g, 4, "out") will be c(4, 3)
I guess
The result will never be NULL, anyway, as it always contains the vertex itself.
G.
Here is the graph:
1 5
1 7
3 2
4 5
4 7
4 9
9 4
6 9
8 7
9 2
best
Xueming
[email protected]
From: Gábor Csárdi
Date: 2014-02-23 23:42
To: Help for igraph users
Subject: Re: [igraph] Error in using the function subcomponent( )
Hi!
On Sun, Feb 23, 2014 at 9:43 AM, [email protected] <[email protected]>
wrote:
Hello!
I am trying to use the subcomponent() to find the in-component and
out-component from a given vertice.
Here is the source code and result:
> g<-read.graph("input.txt", "edgelist")
The "edgelist" file format is indexed from zero, so what is 4 in your file will
be 5 in your graph.
Gabor
> subcomponent(g, 4, "in")
[1] 4
> subcomponent(g, 4, "out")
[1] 4 3
> subcomponent(g, 4, "all")
[1] 4 3 10 5 7 6 8 2 9
Here is the input file "input.txt" (a directed network with 10 nodes and 10
edges):
1 5
1 7
3 2
4 5
4 7
4 9
9 4
6 9
8 7
9 2
But the actual result is should be:
subcomponent(g, 4, "in"): 4 6 9
subcomponent(g, 4, "out"): 2 4 5 7 9
subcomponent(g, 4, "all"): 2 4 5 6 7 9
Why is the results computed by using the function subcomponent( ) different
from the actual result?
best
Xueming
[email protected]
_______________________________________________
igraph-help mailing list
[email protected]
https://lists.nongnu.org/mailman/listinfo/igraph-help
_______________________________________________
igraph-help mailing list
[email protected]
https://lists.nongnu.org/mailman/listinfo/igraph-help_______________________________________________
igraph-help mailing list
[email protected]
https://lists.nongnu.org/mailman/listinfo/igraph-help
