[statnet_help] Assistance with Calculating Degree Centrality in Directed and Valued Networks Using the sna Package in R

[Carter T. Butts via statnet_help]

Hi, Chuding -

Glad that fixed it.   With respect to edgelists vs. adjacency matrices, 
they will give you equivalent results.  If you seem to be getting 
different results, check the two objects: somewhere in your code, you've 
presumably made them non-equivalent....

Best,

-Carter

On 8/26/24 5:59 AM, CHU-DING LING wrote:

>

> Carter,

>

>

> Thank you for your suggestions! The problem has been resolved.

>

> Initially, I imported a matrix from a CSV file and stored it as a 

> matrix class object. I then converted it into a network class object 

> since many functions in *sna* require objects to be of the network 

> class. However, I noticed that the edge weights were lost during the 

> conversion from the matrix object to the network object, which caused 

> the results from the degree() function not to account for edge weights.

>

> Actually, the degree() function can directly handle the matrix object. 

> I also used as.sociomatrix.sna() to convert the original matrix object 

> into another matrix object with a different name. Both approaches 

> produced the same degree centrality results for the directed and 

> valued network.

>

> I also experimented with the as.edgelist.sna() function to convert the 

> original matrix object into an edgelist object. However, when I 

> calculated the degree centrality of this object, it produced incorrect 

> results, with a greater number of elements than the number of nodes in 

> my network. I appreciate if you can give some insights on this issue.

>

> Thanks in advance!

>

> Chuding

>

>

> Carter T. Butts via statnet_help <statnet_help at u.washington.edu> 

> 于2024年8月25日周日 05:15写道：

>

>     H, Chuding -

>

>     The degree() function already exploits edge values; this is its

>     default behavior.  If you wish to /ignore/ edge values, you need

>     to set the "ignore.eval" argument to TRUE.

>

>     If you are not getting valued degree calculations from degree()

>     using the defaults, then you are not passing it valued data.  This

>     may be due to a preprocessing error (so check your inputs). 

>     Another possible failure mode is that you are passing it a network

>     object that has value information stored as an edge attribute, and

>     are expecting degree() to use those edge values.  Since a network

>     object can have any number of edge attributes (or none at all),

>     and they can be of any data type (i.e., not necessarily numeric),

>     degree() can't automagically know what is intended in that case,

>     and will therefore treat the data as unvalued.  An easy way to use

>     edge attribute information is to wrap your object in a call like

>     as.edgelist.sna(<mynet>,attrname=<whateveredgeattributeIwanttouse>),

>     which will extract from the object the specific valued network

>     that you want to analyze.  That's especially handy if you have

>     several different edge values you want to store in the same

>     network object.  Of course, you can also use that same trick to

>     make a "working" edgelist at the top of your script that you reuse

>     for multiple calculations.  (The same can be done with adjacency

>     matrices rather than edgelists, if one prefers.  See e.g.

>     ?as.sociomatrix.sna.)

>

>     Hope that helps,

>

>     -Carter

>

>     On 8/23/24 9:07 PM, CHU-DING LING via statnet_help wrote:

>>

>>     Dear all,

>>

>>     I hope this message finds you well. I am currently working on a

>>     project that involves social network analysis using the *sna*

>>     package in R. I am reaching out to seek your expertise on a

>>     particular issue I have encountered regarding the calculation of

>>     degree centrality in directed and valued networks.

>>

>>     I am working with a directed network where edges have associated

>>     weights. My goal is to accurately calculate both the in-degree

>>     and out-degree centrality of nodes while considering the edge

>>     weights. I attempted to calculate the degree centrality using the

>>     degree function in the *sna* package. While this function works

>>     well for unweighted networks, I realized that it does not account

>>     for edge weights.

>>

>>     Could you please advise on the best method or function within the

>>     *sna* package to accurately calculate the degree centrality in

>>     this context? Though I can make it with *igraph* or other

>>     packages, I am particularly interested in whether *sna* could

>>     directly handle weighted edges in directed networks.

>>

>>     Your guidance would be invaluable, and I would greatly appreciate

>>     any suggestions or resources you might be able to provide. Thank

>>     you for your time and consideration. I look forward to your insights.

>>

>>     Best,

>>

>>     Chuding

>>

>>

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