Add surrogate information to a tree list.

This function adds surrogate variables and adjusted agreement values to a forest that was created by getTreeranger.

Usage

addSurrogates(
  RF,
  trees,
  s,
  Xdata,
  num.threads = parallel::detectCores(),
  preschedule.threads = TRUE
)

Arguments

RF

A ranger::ranger object which was created with keep.inbag = TRUE.

trees

List of trees created by getTreeranger.

s

Predefined number of surrogate splits (it may happen that the actual number of surrogate splits differs in individual nodes).

Xdata

data without the dependent variable.

num.threads

(Default: parallel::detectCores()) Number of threads to spawn for parallelization.

preschedule.threads

(Default: TRUE) Passed as mc.preschedule to parallel::mclapply().

Value

A list of trees. A list of trees containing of lists of nodes with the elements:

• nodeID: ID of the respective node (important for left and right daughters in the next columns)

• leftdaughter: ID of the left daughter of this node

• rightdaughter: ID of the right daughter of this node

• splitvariable: ID of the split variable

• splitpoint: splitpoint of the split variable

• status: 0 for terminal and 1 for non-terminal

• layer: layer information (0 means root node, 1 means 1 layer below root, etc)

• surrogate_i: numbered surrogate variables (number depending on s)

• adj_i: adjusted agreement of variable i