xgb.model.dt.tree

From xgboost v0.6-3 by Tong He

Parse a boosted tree model text dump

Parse a boosted tree model text dump into a data.table structure.

Usage

xgb.model.dt.tree(feature_names = NULL, model = NULL, text = NULL, n_first_tree = NULL)

Arguments

feature_names: character vector of feature names. If the model already contains feature names, this argument should be NULL (default value)
model: object of class xgb.Booster
text: character vector previously generated by the xgb.dump function (where parameter with_stats = TRUE should have been set).
n_first_tree: limit the parsing to the n first trees. If set to NULL, all trees of the model are parsed.

Value

A data.table with detailed information about model trees' nodes.The columns of the data.table are:

Tree: ID of a tree in a model
Node: ID of a node in a tree
ID: unique identifier of a node in a model
Feature: for a branch node, it's a feature id or name (when available); for a leaf note, it simply labels it as 'Leaf'
Split: location of the split for a branch node (split condition is always "less than")
Yes: ID of the next node when the split condition is met
No: ID of the next node when the split condition is not met
Missing: ID of the next node when branch value is missing
Quality: either the split gain (change in loss) or the leaf value
Cover: metric related to the number of observation either seen by a split or collected by a leaf during training.

Examples

# Basic use:

data(agaricus.train, package='xgboost')

bst <- xgboost(data = agaricus.train$data, label = agaricus.train$label, max_depth = 2, 
               eta = 1, nthread = 2, nrounds = 2,objective = "binary:logistic")

(dt <- xgb.model.dt.tree(colnames(agaricus.train$data), bst))


# How to match feature names of splits that are following a current 'Yes' branch:

merge(dt, dt[, .(ID, Y.Feature=Feature)], by.x='Yes', by.y='ID', all.x=TRUE)[order(Tree,Node)]

Documentation reproduced from package xgboost, version 0.6-3, License: Apache License (== 2.0) | file LICENSE

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