How to convert the lower triangle of a matrix to a symmetric matrix

See this thread.

This post was updated.

From Similarity To Distance matrix


# This function returns an object of class "dist"
sim2dist <- function(mx) as.dist(sqrt(outer(diag(mx), diag(mx), "+") - 2*mx)) # from similarity to distance matrix d.mx = as.matrix(d.mx) d.mx = sim2dist(d.mx) # The distance matrix can be used to visualize # hierarchical clustering results as dendrograms hc = hclust(d.mx) plot(hc)

See Multivariate Analysis (Probability and Mathematical Statistics) for the statistical theory.