A function to fit the tree with look-ahead option
REmrt_GS_(mf, maxL, minbucket, minsplit, cp, lookahead)the data.frame to grow the tree
the maximum number of splits
the minimum number of the studies in a terminal node
the minimal number of studies in a parent node to be split
the stopping rule for decrease of between-subgroups Q. Any split that does not decrease the between-subgroups Q is not attempted.
an argument indicating whether to apply the "look-ahead" strategy when fitting the tree
a list including a tree, the split points, the data, and the nodes after each split