xgb.plot.tree
Plot a boosted tree model
Read a tree model text dump and plot the model.
Usage
xgb.plot.tree(feature_names = NULL, model = NULL, trees = NULL,
plot_width = NULL, plot_height = NULL, render = TRUE,
show_node_id = FALSE, ...)Arguments
- feature_names
names of each feature as a
charactervector.- model
produced by the
xgb.trainfunction.- trees
an integer vector of tree indices that should be visualized. If set to
NULL, all trees of the model are included. IMPORTANT: the tree index in xgboost model is zero-based (e.g., usetrees = 0:2for the first 3 trees in a model).- plot_width
the width of the diagram in pixels.
- plot_height
the height of the diagram in pixels.
- render
a logical flag for whether the graph should be rendered (see Value).
- show_node_id
a logical flag for whether to show node id's in the graph.
- ...
currently not used.
Details
The content of each node is organised that way:
Feature name.
Cover: The sum of second order gradient of training data classified to the leaf. If it is square loss, this simply corresponds to the number of instances seen by a split or collected by a leaf during training. The deeper in the tree a node is, the lower this metric will be.Gain(for split nodes): the information gain metric of a split (corresponds to the importance of the node in the model).Value(for leafs): the margin value that the leaf may contribute to prediction.
The tree root nodes also indicate the Tree index (0-based).
The "Yes" branches are marked by the "< split_value" label. The branches that also used for missing values are marked as bold (as in "carrying extra capacity").
This function uses GraphViz as a backend of DiagrammeR.
Value
When render = TRUE:
returns a rendered graph object which is an htmlwidget of class grViz.
Similar to ggplot objects, it needs to be printed to see it when not running from command line.
When render = FALSE:
silently returns a graph object which is of DiagrammeR's class dgr_graph.
This could be useful if one wants to modify some of the graph attributes
before rendering the graph with render_graph.
Examples
# NOT RUN {
data(agaricus.train, package='xgboost')
bst <- xgboost(data = agaricus.train$data, label = agaricus.train$label, max_depth = 3,
eta = 1, nthread = 2, nrounds = 2,objective = "binary:logistic")
# plot all the trees
xgb.plot.tree(model = bst)
# plot only the first tree and display the node ID:
xgb.plot.tree(model = bst, trees = 0, show_node_id = TRUE)
# }
# NOT RUN {
# Below is an example of how to save this plot to a file.
# Note that for `export_graph` to work, the DiagrammeRsvg and rsvg packages must also be installed.
library(DiagrammeR)
gr <- xgb.plot.tree(model=bst, trees=0:1, render=FALSE)
export_graph(gr, 'tree.pdf', width=1500, height=1900)
export_graph(gr, 'tree.png', width=1500, height=1900)
# }
# NOT RUN {
# }