[Rsiena-help] Effects of covariate similarity on the evolution of a bipartite graph?

[Matteo Gagliolo]

Dear Tom,

       I really need this effect in my research, so I'll see what I can do and 
keep you posted. Help from other users is obviously more than 
welcome! 

Best regards,  

Matteo

On Monday 08 October 2012 17:04:06 you wrote:
> Dear Matteo,
> 
> That is an interesting topic. For the moment this effect has been
> blacklisted only because this distance-2 effect still needs to be checked
> once more (also in its one-mode version) and because the filtering of
> effects to allow them in the 2-mode version still is incomplete. You are
> right that it should be allowed in. If you (or anyone) wishes to contribute
> and speed this up, then the first thing would be to check that the target
> statistics for this effect in its one-mode version as reported in the
> output are identical to what one should expect from the definition of the
> effect in the manual. This will be the first thing I would want to do as a
> first step to incorporate this effect in the two-mode version. Best wishes,
> Tom
> 
> ================================================================
> Tom A.B. Snijders
> Professor of Statistics in the Social Sciences
> Department of Politics and Department of Statistics
> Nuffield College
> University of Oxford
> tel. +44-01865-278599
> 
> 
> -----Original Message-----
> From: rsiena-help-bounces at lists.r-forge.r-project.org
> [mailto:rsiena-help-bounces at lists.r-forge.r-project.org] On Behalf Of
> Matteo Gagliolo Sent: 08 October 2012 15:33
> To: rsiena-help at lists.r-forge.r-project.org
> Subject: [Rsiena-help] Effects of covariate similarity on the evolution of a
> bipartite graph?
> 
> Dear RSiena users,
> 
>         I'm trying to analyze a two-mode network representing interlocking
> directorates. I have covariates for the mode corresponding to boards, and I
> would like to see if there is a tendency of directors to join boards with
> similar covariates (or equivalently, a tendency of boards to form
> interlocks with similar boards). Sort of an homophily at distance 2.
> 
> Taking the boards as mode one, I think this effect could be implemented as
> an interaction among egoX and altDist2, as the latter would represent the
> average X of boards on which a certain director is already sitting.
> 
> Here comes my problem: altDist2 is currently "blacklisted" in the code for
> bipartite nets. Diving into the code (RSienaTest r. 220) I found out where
> it all happens: in file effects.r:773, function covarBipartiteEff (comments
> are mine, to explain the issue): ---
> covarBipartiteEff<- function(covarname, poszvar, moreThan2, nodesetNbr,
>                                  name)
>     {
>         covRateEffects  <-  NULL
>         if (nodesetNbr == 1)
>         {#This is the branch taken as the covariate is on the 1st
> mode(boards) covObjEffects <-
>                 createEffects("covarBipartiteObjective", covarname,
>                               name=varname,
>                               groupName=groupName, group=group,
>                               netType=netType) #This returns "altX" 
> "altSqX" "egoX"    "altDist2" "simDist2", each replicated as
> eval/creat/endow covObjEffects <-
>                 covObjEffects[covObjEffects$shortName %in%
>                               c("egoX"), ] #Here only "egoX" effects are
> selected ---
> 
> So, it seems the code is currently allowing only for egoX effects for
> covariates of the 1st mode.
> 
> Does anyone have an idea why? As all distance 2 nodes are in the same mode,
> I don't see why altDist2 and simDist2 should be blacklisted.
> 
> Or maybe there is a more correct way to implement the "distance 2 homophily"
> I am interested in?
> 
> Thanks,
> 
> Matteo
> 
> --
> Matteo Gagliolo <mgagliol at ulb.ac.be>
> Group for research on Ethnic Relations, Migration and Equality (GERME),
> Institute of Sociology; Machine Learning Group (MLG), Computer Science
> Department. Université Libre de Bruxelles (ULB).
> GERME, ULB, CP 124, 44 av. Jeanne
> 1050 Brussels, Belgium
> Phone +32 2 650 4798, Fax +32 2 650 4659
> http://homepages.ulb.ac.be/~mgagliol/
> 
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> Nuffield College, New Road, Oxford, OX1 1NF
-- 
Matteo Gagliolo <mgagliol at ulb.ac.be>
Group for research on Ethnic Relations, Migration and Equality (GERME),
Institute of Sociology;
Machine Learning Group (MLG), Computer Science Department.
Université Libre de Bruxelles (ULB).
GERME, ULB, CP 124, 44 av. Jeanne
1050 Brussels, Belgium
Phone +32 2 650 4798, Fax +32 2 650 4659
http://homepages.ulb.ac.be/~mgagliol/