Find Connected Components in a NN Graph
Generic function and methods to find connected components in nearest neighbor graphs.
comps(x, ...) ## S3 method for class 'dist' comps(x, eps, ...) ## S3 method for class 'kNN' comps(x, mutual = FALSE, ...) ## S3 method for class 'sNN' comps(x, ...) ## S3 method for class 'frNN' comps(x, ...)
Note that for kNN graphs, one point may be in the kNN of the other but nor vice versa.
mutual = TRUE requires that both points are in each other's kNN.
a integer vector with component assignments.
Michael Hahsler
set.seed(665544) n <- 100 x <- cbind( x=runif(10, 0, 5) + rnorm(n, sd = 0.4), y=runif(10, 0, 5) + rnorm(n, sd = 0.4) ) plot(x, pch = 16) # Connected components on a graph where each pair of points # with a distance less or equal to eps are connected d <- dist(x) components <- comps(d, eps = .8) plot(x, col = components, pch = 16) # Connected components in a fixed radius nearest neighbor graph # Gives the same result as the threshold on the distances above frnn <- frNN(x, eps = .8) components <- comps(frnn) plot(frnn, data = x, col = components) # Connected components on a k nearest neighbors graph knn <- kNN(x, 3) components <- comps(knn, mutual = FALSE) plot(knn, data = x, col = components) components <- comps(knn, mutual = TRUE) plot(knn, data = x, col = components) # Connected components in a shared nearest neighbor graph snn <- sNN(x, k = 10, kt = 5) components <- comps(snn) plot(snn, data = x, col = components)
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