pretty.gbm.tree: Print gbm tree components

In gbm: Generalized Boosted Regression Models

Print gbm tree components

Description

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.

Usage

## S3 method for class 'gbm.tree'
pretty(object, i.tree = 1)

Arguments

object	a gbm.object initially fit using gbm
i.tree	the index of the tree component to extract from object and display

Value

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.

Author(s)

Greg Ridgeway [e-mail]

See Also

gbm, gbm.object

gbm documentation built on June 28, 2024, 9:07 a.m.