condense
.
reduce.nn(train, ind, class)
condense
).
All the members of the training set are tried in random order. Any which when dropped do not cause any members of the training set to be wrongly classified are dropped.
Gates, G.W. (1972) The reduced nearest neighbor rule. IEEE Trans. Information Theory IT-18, 431-432.
train <- rbind(iris[1:25,,1],iris[1:25,,2],iris[1:25,,3]) test <- rbind(iris[26:50,,1],iris[26:50,,2],iris[26:50,,3]) cl <- factor(c(rep("s",25),rep("c",25), rep("v",25))) set.seed(99) keep <- condense(train, cl) knn(train[keep,], test, cl[keep]) keep2 <- reduce.nn(train, keep, cl) knn(train[keep2,], test, cl[keep2])