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.
1  pretty.gbm.tree(object, i.tree = 1)

object 
a 
i.tree 
the index of the tree component to extract from 
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 
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 gregridgeway@gmail.com
Questions? Problems? Suggestions? Tweet to @rdrrHQ or email at ian@mutexlabs.com.
All documentation is copyright its authors; we didn't write any of that.