handle issue #93

[briatte]

• Solves the second part of issue randomly failing test #93.
• Works around the first part of issue randomly failing test #93.

The problem remains that I do not know how to avoid conflicts with igraph. If the user loads igraph after loading ggnet / ggnet2 / GGally, then it's easy to get this error:

> ggnet2(n, size = "degree")
 Error in is.bipartite(x) : Not a graph object 
5 stop("Not a graph object") 
4 is.bipartite(x) 
3 as.edgelist.sna(dat) 
2 sna::degree(net, gmode = is_dir, cmode = ifelse(x == "degree", 
    "freeman", x)) at ggnet2.R#484
1 ggnet2(n, size = "degree") 

[briatte]

Quick update: just in case we reintroduce igraph in the Suggests of GGally, as @elbamos suggests in #100, I have found a way to avoid any namespace conflict between it and sna.

The protection looks like this for ggnet (and is almost identical for ggnet2):

# prevent namespace conflict with igraph
if ("package:igraph" %in% search()) {
  y = ifelse(is_dir == "digraph", "directed", "undirected")
  z = c("indegree" = "in", "outdegree" = "out", "degree" = "all", "freeman" = "all")[ x ]
  data$weight = igraph::degree(igraph::graph.adjacency(as.matrix(net), mode = y), mode = z)
} else {
  data$weight = sna::degree(net, gmode = is_dir, cmode = ifelse(x == "degree", "freeman", x))
}

The code does not even need to know if igraph is loaded before network or sna—if igraph is loaded, it falls back to its own degree centrality function.

[elbamos]

That's great! Can you share? I'll take a look and possibly integrate when I take a look at the whole thing.

On Sep 18, 2015, at 12:52 PM, François Briatte notifications@github.com wrote:

Quick update: just in case we reintroduce igraph in the Suggests of GGally, as @elbamos suggests in #100, I have found a way to avoid any namespace conflict between it and sna.

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Reply to this email directly or view it on GitHub.

[briatte]

The code is in my comment above. If igraph is anywhere in the search() path, then the code converts the two objects that give the directedness and the centrality mode to their igraph equivalents, reconstructs an igraph object from the adjacency matrix of the network object, and computes centrality from that object.

This operation should never take too long except on very, very large graphs, and it should work fine on any binary one-mode adjacency matrix.

P.S. ggnetworkmap does not require the workaround since it does not call sna::degree.

[schloerke]

Looks like a good solution to me!