Re: [igraph] Cayley Tree

[Gábor Csárdi]

I think it actually should be graph.tree(coord+1, coord,
mode="undir"). So the correct function is

cayley.tree <- function(coord, depth) {
 if (depth==0) return(graph.empty(1))
 if (depth==1) return(graph.tree(coord+1, coord, mode="undir"))
 d <- coord-1
 n1 <- (d^(depth+1)-1) / (d-1)
 n2 <- (d^depth -1)/ (d-1)
 g <- graph.tree(n1, d, mode="undir") %du% graph.tree(n2, d, mode="undir")
 add.edges(g, c(0, n1))
}

and similarly for the Python version. Best,
Gabor

On Mon, Nov 23, 2009 at 1:00 PM, Tamas Nepusz <address@hidden> wrote:
>> I am not sure about this:
>>
>>  if depth == 1:
>>        return Graph.Tree(4, 3)
> Indeed, it should be Graph.Tree(coord, coord-1) and a similar correction
> should also be made in the R variant.
>
> --
> Tamas
>
>
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-- 
Gabor Csardi <address@hidden>     UNIL DGM