Print gbm tree components
gbm stores the collection of trees used to construct the model in a
compact matrix structure. This function extracts the information from a single
tree and displays it in a slightly more readable form. This function is mostly
for debugging purposes and to satisfy some users' curiosity.
pretty.gbm.tree(object, i.tree = 1)
pretty.gbm.treereturns a data frame. Each row corresponds to a node in the tree. Columns indicate
SplitVar index of which variable is used to split. -1 indicates a terminal node. SplitCodePred if the split variable is continuous then this component is the split point. If the split variable is categorical then this component contains the index of
object$c.splitthat describes the categorical split. If the node is a terminal node then this is the prediction.
LeftNode the index of the row corresponding to the left node. RightNode the index of the row corresponding to the right node. ErrorReduction the reduction in the loss function as a result of splitting this node. Weight the total weight of observations in the node. If weights are all equal to 1 then this is the number of observations in the node.