R: Print gbm tree components

pretty.gbm.tree {gbm} | R Documentation

## 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

    pretty.gbm.tree(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 gregridgeway@gmail.com

### See Also

`gbm`, `gbm.object`

[Package gbm version 2.1.3 Index]