diff --git a/R/clusternum.R b/R/clusternum.R
new file mode 100644
index 0000000..dbdcdbb
--- /dev/null
+++ b/R/clusternum.R
@@ -0,0 +1,16 @@
+clusternum <- function(X, T, k, c) {
+	m <- size(X, 1) + 1
+	while (!is.null(k)) {
+		# % Get the children of nodes at this level
+		children <- X[k, 1:2]
+		children <- children[, ]
+
+		# % Assign this node number to leaf children
+		t <- (children <= m)
+		T[children(t)] <- c
+
+		# % Move to next level
+		k <- children(!t) - m
+	}
+	return(T)
+}