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## Re: [igraph] weighted pagerank?

**From**: |
Csardi Gabor |

**Subject**: |
Re: [igraph] weighted pagerank? |

**Date**: |
Sat, 23 Aug 2008 16:02:25 +0200 |

**User-agent**: |
Mutt/1.5.9i |

Eytan,
the difference is more than 50 percent. I guess it would be more
if the weights were not uniformly distributed.
>* library(igraph)*
>* g <- simplify(ba.game(1000, m=5))*
>* pg1 <- page.rank(g)*
>* pg2 <- page.rank(g, weights=runif(ecount(g),1,1000))*
>* max( (pg1$vector - pg2$vector) / pg1$vector)*
[1] 0.5442513
Gabor
On Fri, Aug 22, 2008 at 07:18:30PM -0400, Eytan Bakshy wrote:
>* Hello,*
>* *
>* I am using igraph 0.51 in R and igraph 0.5 in python, and it doesn't *
>* seem that specifying edge weights has any effect in either *
>* implementation. I know that the igraph 0.5 release announcement *
>* mentions that Page Rank and the fast greedy algorithm supports edge *
>* weights, but is this just in the C library.*
>* *
>* In python, I tried creating several graphs where edges have the *
>* attribute 'weight', which were floats. I am trying to compute the *
>* weighted pagerank by saying:*
>* prw = g.pagerank(weights='weight')*
>* *
>* and if i do:*
>* pr = g.pagerank()*
>* the following statement yields True:*
>* prw == pr*
>* *
>* on several graphs using edge weights that were distributed uniformly *
>* at random between (0,1), and then again between (1,1000)*
>* *
>* *
>* I am pretty new to R, but it appears that the same thing holds using *
>* page.rank(g, weights=runif(length(E(g)),1,10000))*
>* *
>* *
>* Thanks,*
>* Eytan*
>* *
>* *
>* _______________________________________________*
>* igraph-help mailing list*
>* address@hidden*
>* http://lists.nongnu.org/mailman/listinfo/igraph-help*
--
Csardi Gabor <address@hidden> MTA RMKI, ELTE TTK