# Decision Tree Model for Regression and Classification

`spark.decisionTree.Rd`

`spark.decisionTree`

fits a Decision Tree Regression model or Classification model on
a SparkDataFrame. Users can call `summary`

to get a summary of the fitted Decision Tree
model, `predict`

to make predictions on new data, and `write.ml`

/`read.ml`

to
save/load fitted models.
For more details, see
Decision Tree Regression and
Decision Tree Classification

## Usage

```
spark.decisionTree(data, formula, ...)
# S4 method for SparkDataFrame,formula
spark.decisionTree(
data,
formula,
type = c("regression", "classification"),
maxDepth = 5,
maxBins = 32,
impurity = NULL,
seed = NULL,
minInstancesPerNode = 1,
minInfoGain = 0,
checkpointInterval = 10,
maxMemoryInMB = 256,
cacheNodeIds = FALSE,
handleInvalid = c("error", "keep", "skip")
)
# S4 method for DecisionTreeRegressionModel
summary(object)
# S3 method for summary.DecisionTreeRegressionModel
print(x, ...)
# S4 method for DecisionTreeClassificationModel
summary(object)
# S3 method for summary.DecisionTreeClassificationModel
print(x, ...)
# S4 method for DecisionTreeRegressionModel
predict(object, newData)
# S4 method for DecisionTreeClassificationModel
predict(object, newData)
# S4 method for DecisionTreeRegressionModel,character
write.ml(object, path, overwrite = FALSE)
# S4 method for DecisionTreeClassificationModel,character
write.ml(object, path, overwrite = FALSE)
```

## Arguments

- data
a SparkDataFrame for training.

- formula
a symbolic description of the model to be fitted. Currently only a few formula operators are supported, including '~', ':', '+', and '-'.

- ...
additional arguments passed to the method.

- type
type of model, one of "regression" or "classification", to fit

- maxDepth
Maximum depth of the tree (>= 0).

- maxBins
Maximum number of bins used for discretizing continuous features and for choosing how to split on features at each node. More bins give higher granularity. Must be >= 2 and >= number of categories in any categorical feature.

- impurity
Criterion used for information gain calculation. For regression, must be "variance". For classification, must be one of "entropy" and "gini", default is "gini".

- seed
integer seed for random number generation.

- minInstancesPerNode
Minimum number of instances each child must have after split.

- minInfoGain
Minimum information gain for a split to be considered at a tree node.

- checkpointInterval
Param for set checkpoint interval (>= 1) or disable checkpoint (-1). Note: this setting will be ignored if the checkpoint directory is not set.

- maxMemoryInMB
Maximum memory in MiB allocated to histogram aggregation.

- cacheNodeIds
If FALSE, the algorithm will pass trees to executors to match instances with nodes. If TRUE, the algorithm will cache node IDs for each instance. Caching can speed up training of deeper trees. Users can set how often should the cache be checkpointed or disable it by setting checkpointInterval.

- handleInvalid
How to handle invalid data (unseen labels or NULL values) in features and label column of string type in classification model. Supported options: "skip" (filter out rows with invalid data), "error" (throw an error), "keep" (put invalid data in a special additional bucket, at index numLabels). Default is "error".

- object
A fitted Decision Tree regression model or classification model.

- x
summary object of Decision Tree regression model or classification model returned by

`summary`

.- newData
a SparkDataFrame for testing.

- path
The directory where the model is saved.

- overwrite
Overwrites or not if the output path already exists. Default is FALSE which means throw exception if the output path exists.

## Value

`spark.decisionTree`

returns a fitted Decision Tree model.

`summary`

returns summary information of the fitted model, which is a list.
The list of components includes `formula`

(formula),

`numFeatures`

(number of features), `features`

(list of features),

`featureImportances`

(feature importances), and `maxDepth`

(max depth of
trees).

`predict`

returns a SparkDataFrame containing predicted labeled in a column named
"prediction".

## Note

spark.decisionTree since 2.3.0

summary(DecisionTreeRegressionModel) since 2.3.0

print.summary.DecisionTreeRegressionModel since 2.3.0

summary(DecisionTreeClassificationModel) since 2.3.0

print.summary.DecisionTreeClassificationModel since 2.3.0

predict(DecisionTreeRegressionModel) since 2.3.0

predict(DecisionTreeClassificationModel) since 2.3.0

write.ml(DecisionTreeRegressionModel, character) since 2.3.0

write.ml(DecisionTreeClassificationModel, character) since 2.3.0

## Examples

```
if (FALSE) {
# fit a Decision Tree Regression Model
df <- createDataFrame(longley)
model <- spark.decisionTree(df, Employed ~ ., type = "regression", maxDepth = 5, maxBins = 16)
# get the summary of the model
summary(model)
# make predictions
predictions <- predict(model, df)
# save and load the model
path <- "path/to/model"
write.ml(model, path)
savedModel <- read.ml(path)
summary(savedModel)
# fit a Decision Tree Classification Model
t <- as.data.frame(Titanic)
df <- createDataFrame(t)
model <- spark.decisionTree(df, Survived ~ Freq + Age, "classification")
}
```