R/rand.index.R

In feiyoung/simutool: Common Tool Functions In Simulation

rand.index <-
  function(group1, group2) {
    #which points are in the same vs different groups? different groups == 1, same == 0
    x <- abs(sapply(group1, function(x) x-group1))
    x[x > 1] <- 1
    y <- abs(sapply(group2, function(x) x-group2))
    y[y > 1] <- 1
    #what pairs share the same relationships between group1 and group2 (same/same or different/different)
    sg <- sum(abs(x-y))/2
    bc <- choose(dim(x)[1],2)
    ri <- 1-sg/bc
    return(ri)
  }