尝试在推文数据中找到社区。不同单词之间的余弦相似度形成邻接矩阵。然后,我使用邻接矩阵创建了图形。这里的任务是可视化图形。
# Document Term Matrix
dtm = DocumentTermMatrix(tweets)
### adjust threshold here
dtms = removeSparseTerms(dtm, 0.998)
dim(dtms)
# cosine similarity matrix
t = as.matrix(dtms)
# comparing two word feature vectors
#cosine(t[,"yesterday"], t[,"yet"])
numWords = dim(t)[2]
# cosine measure between all column vectors of a matrix.
adjMat = cosine(t)
r = 3
for(i in 1:numWords)
{
highElement = sort(adjMat[i,], partial=numWords-r)[numWords-r]
adjMat[i,][adjMat[i,] < highElement] = 0
}
# build graph from the adjacency matrix
g = graph.adjacency(adjMat, weighted=TRUE, mode="undirected", diag=FALSE)
V(g)$name
# remove loop and multiple edges
g = simplify(g)
wt = walktrap.community(g, steps=5) # default steps=2
table(membership(wt))
# set vertex color & size
nodecolor = rainbow(length(table(membership(wt))))[as.vector(membership(wt))]
nodesize = as.matrix(round((log2(10*membership(wt)))))
nodelayout = layout.fruchterman.reingold(g,niter=1000,area=vcount(g)^1.1,repulserad=vcount(g)^10.0, weights=NULL)
par(mai=c(0,0,1,0))
plot(g,
layout=nodelayout,
vertex.size = nodesize,
vertex.label=NA,
vertex.color = nodecolor,
edge.arrow.size=0.2,
edge.color="grey",
edge.width=1)
我希望将不同的簇/社区之间留出更多的间隔。
area = vcount(graph)^2
(http://www.inside-r.org/packages/cran/igraph/docs/layout) - Jon Cardoso-Silvawrite.graph(g,file="graph.gml",format="gml")
命令来生成GML文件,然后将该文件加载到Gephi中。 - Jon Cardoso-Silva