pretty.gbm.tree {gbm} | R Documentation |
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)
object |
a gbm.object initially fit using gbm |
i.tree |
the index of the tree component to extract from object
and display |
pretty.gbm.tree
returns 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.split that 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. |
Greg Ridgeway gregr@rand.org