Package org.apache.spark.ml.classification

Class RandomForestClassificationModel

Object

org.apache.spark.ml.PipelineStage

org.apache.spark.ml.Transformer

org.apache.spark.ml.Model<M>

org.apache.spark.ml.PredictionModel<FeaturesType,M>

org.apache.spark.ml.classification.ClassificationModel<FeaturesType,M>

org.apache.spark.ml.classification.ProbabilisticClassificationModel<Vector,RandomForestClassificationModel>

org.apache.spark.ml.classification.RandomForestClassificationModel

All Implemented Interfaces:

Serializable, org.apache.spark.internal.Logging, ClassifierParams, ProbabilisticClassifierParams, Params, HasCheckpointInterval, HasFeaturesCol, HasLabelCol, HasPredictionCol, HasProbabilityCol, HasRawPredictionCol, HasSeed, HasThresholds, HasWeightCol, PredictorParams, DecisionTreeParams, RandomForestClassifierParams, RandomForestParams, TreeClassifierParams, TreeEnsembleClassifierParams, TreeEnsembleModel<DecisionTreeClassificationModel>, TreeEnsembleParams, HasTrainingSummary<RandomForestClassificationTrainingSummary>, Identifiable, MLWritable

public class RandomForestClassificationModel
extends ProbabilisticClassificationModel<Vector,RandomForestClassificationModel>
implements RandomForestClassifierParams, TreeEnsembleModel<DecisionTreeClassificationModel>, MLWritable, Serializable, HasTrainingSummary<RandomForestClassificationTrainingSummary>

Random Forest model for classification. It supports both binary and multiclass labels, as well as both continuous and categorical features.

param: _trees Decision trees in the ensemble. Warning: These have null parents.

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.spark.internal.Logging

org.apache.spark.internal.Logging.LogStringContext, org.apache.spark.internal.Logging.SparkShellLoggingFilter

Method Summary

Modifier and Type	Method	Description
BinaryRandomForestClassificationTrainingSummary	binarySummary()	Gets summary of model on training set.
final BooleanParam	bootstrap()	Whether bootstrap samples are used when building trees.
final BooleanParam	cacheNodeIds()	If false, the algorithm will pass trees to executors to match instances with nodes.
final IntParam	checkpointInterval()	Param for set checkpoint interval (>= 1) or disable checkpoint (-1).
RandomForestClassificationModel	copy(ParamMap extra)	Creates a copy of this instance with the same UID and some extra params.
long	estimatedSize()
RandomForestClassificationSummary	evaluate(Dataset<?> dataset)	Evaluates the model on a test dataset.
Vector	featureImportances()
final Param<String>	featureSubsetStrategy()	The number of features to consider for splits at each tree node.
final Param<String>	impurity()	Criterion used for information gain calculation (case-insensitive).
final Param<String>	leafCol()	Leaf indices column name.
static RandomForestClassificationModel	load(String path)
final IntParam	maxBins()	Maximum number of bins used for discretizing continuous features and for choosing how to split on features at each node.
final IntParam	maxDepth()	Maximum depth of the tree (nonnegative).
final IntParam	maxMemoryInMB()	Maximum memory in MB allocated to histogram aggregation.
final DoubleParam	minInfoGain()	Minimum information gain for a split to be considered at a tree node.
final IntParam	minInstancesPerNode()	Minimum number of instances each child must have after split.
final DoubleParam	minWeightFractionPerNode()	Minimum fraction of the weighted sample count that each child must have after split.
int	numClasses()	Number of classes (values which the label can take).
int	numFeatures()	Returns the number of features the model was trained on.
final IntParam	numTrees()	Number of trees to train (at least 1).
Vector	predictRaw(Vector features)	Raw prediction for each possible label.
static MLReader<RandomForestClassificationModel>	read()
final LongParam	seed()	Param for random seed.
final DoubleParam	subsamplingRate()	Fraction of the training data used for learning each decision tree, in range (0, 1].
RandomForestClassificationTrainingSummary	summary()	Gets summary of model on training set.
String	toString()	Summary of the model
int	totalNumNodes()	Total number of nodes, summed over all trees in the ensemble.
Dataset<Row>	transform(Dataset<?> dataset)	Transforms dataset by reading from PredictionModel.featuresCol(), and appending new columns as specified by parameters: - predicted labels as PredictionModel.predictionCol() of type Double - raw predictions (confidences) as ClassificationModel.rawPredictionCol() of type Vector - probability of each class as ProbabilisticClassificationModel.probabilityCol() of type Vector.
StructType	transformSchema(StructType schema)	Check transform validity and derive the output schema from the input schema.
DecisionTreeClassificationModel[]	trees()	Trees in this ensemble.
double[]	treeWeights()	Weights for each tree, zippable with TreeEnsembleModel.trees()
String	uid()	An immutable unique ID for the object and its derivatives.
final Param<String>	weightCol()	Param for weight column name.
MLWriter	write()	Returns an MLWriter instance for this ML instance.

Methods inherited from class org.apache.spark.ml.classification.ProbabilisticClassificationModel

normalizeToProbabilitiesInPlace, predictProbability, probabilityCol, setProbabilityCol, setThresholds, thresholds

Methods inherited from class org.apache.spark.ml.classification.ClassificationModel

predict, rawPredictionCol, setRawPredictionCol, transformImpl

Methods inherited from class org.apache.spark.ml.PredictionModel

featuresCol, labelCol, predictionCol, setFeaturesCol, setPredictionCol

Methods inherited from class org.apache.spark.ml.Model

hasParent, parent, setParent

Methods inherited from class org.apache.spark.ml.Transformer

transform, transform, transform

Methods inherited from class org.apache.spark.ml.PipelineStage

params

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.spark.ml.tree.DecisionTreeParams

getCacheNodeIds, getLeafCol, getMaxBins, getMaxDepth, getMaxMemoryInMB, getMinInfoGain, getMinInstancesPerNode, getMinWeightFractionPerNode, getOldStrategy, setLeafCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasCheckpointInterval

getCheckpointInterval

Methods inherited from interface org.apache.spark.ml.param.shared.HasFeaturesCol

featuresCol, getFeaturesCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasLabelCol

getLabelCol, labelCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasPredictionCol

getPredictionCol, predictionCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasProbabilityCol

getProbabilityCol, probabilityCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasRawPredictionCol

getRawPredictionCol, rawPredictionCol

Methods inherited from interface org.apache.spark.ml.param.shared.HasSeed

getSeed

Methods inherited from interface org.apache.spark.ml.param.shared.HasThresholds

getThresholds, thresholds

Methods inherited from interface org.apache.spark.ml.util.HasTrainingSummary

hasSummary, setSummary

Methods inherited from interface org.apache.spark.ml.param.shared.HasWeightCol

getWeightCol

Methods inherited from interface org.apache.spark.internal.Logging

initializeForcefully, initializeLogIfNecessary, initializeLogIfNecessary, initializeLogIfNecessary$default$2, isTraceEnabled, log, logBasedOnLevel, logDebug, logDebug, logDebug, logDebug, logError, logError, logError, logError, logInfo, logInfo, logInfo, logInfo, logName, LogStringContext, logTrace, logTrace, logTrace, logTrace, logWarning, logWarning, logWarning, logWarning, org$apache$spark$internal$Logging$$log_, org$apache$spark$internal$Logging$$log__$eq, withLogContext

Methods inherited from interface org.apache.spark.ml.util.MLWritable

save

Methods inherited from interface org.apache.spark.ml.param.Params

clear, copyValues, defaultCopy, defaultParamMap, estimateMatadataSize, explainParam, explainParams, extractParamMap, extractParamMap, get, getDefault, getOrDefault, getParam, hasDefault, hasParam, isDefined, isSet, onParamChange, paramMap, params, set, set, set, setDefault, setDefault, shouldOwn

Methods inherited from interface org.apache.spark.ml.tree.RandomForestParams

getBootstrap, getNumTrees

Methods inherited from interface org.apache.spark.ml.tree.TreeClassifierParams

getImpurity, getOldImpurity

Methods inherited from interface org.apache.spark.ml.tree.TreeEnsembleClassifierParams

validateAndTransformSchema

Methods inherited from interface org.apache.spark.ml.tree.TreeEnsembleModel

getEstimatedSize, getLeafField, getTree, javaTreeWeights, predictLeaf, toDebugString

Methods inherited from interface org.apache.spark.ml.tree.TreeEnsembleParams

getFeatureSubsetStrategy, getOldStrategy, getSubsamplingRate

Method Details

read

public static MLReader<RandomForestClassificationModel> read()

load

public static RandomForestClassificationModel load(String path)

totalNumNodes

public int totalNumNodes()

Description copied from interface: TreeEnsembleModel

Total number of nodes, summed over all trees in the ensemble.

Specified by:

totalNumNodes in interface TreeEnsembleModel<DecisionTreeClassificationModel>

impurity

public final Param<String> impurity()

Description copied from interface: TreeClassifierParams

Criterion used for information gain calculation (case-insensitive). This impurity type is used in DecisionTreeClassifier and RandomForestClassifier, Supported: "entropy" and "gini". (default = gini)

Specified by:

impurity in interface TreeClassifierParams

Returns:

(undocumented)

numTrees

public final IntParam numTrees()

Description copied from interface: RandomForestParams

Number of trees to train (at least 1). If 1, then no bootstrapping is used. If greater than 1, then bootstrapping is done. TODO: Change to always do bootstrapping (simpler). SPARK-7130 (default = 20)

Note: The reason that we cannot add this to both GBT and RF (i.e. in TreeEnsembleParams) is the param maxIter controls how many trees a GBT has. The semantics in the algorithms are a bit different.

Specified by:

numTrees in interface RandomForestParams

Returns:

(undocumented)

bootstrap

public final BooleanParam bootstrap()

Description copied from interface: RandomForestParams

Whether bootstrap samples are used when building trees.

Specified by:

bootstrap in interface RandomForestParams

Returns:

(undocumented)

subsamplingRate

public final DoubleParam subsamplingRate()

Description copied from interface: TreeEnsembleParams

Fraction of the training data used for learning each decision tree, in range (0, 1]. (default = 1.0)

Specified by:

subsamplingRate in interface TreeEnsembleParams

Returns:

(undocumented)

featureSubsetStrategy

public final Param<String> featureSubsetStrategy()

Description copied from interface: TreeEnsembleParams

The number of features to consider for splits at each tree node. Supported options: - "auto": Choose automatically for task: If numTrees == 1, set to "all." If numTrees greater than 1 (forest), set to "sqrt" for classification and to "onethird" for regression. - "all": use all features - "onethird": use 1/3 of the features - "sqrt": use sqrt(number of features) - "log2": use log2(number of features) - "n": when n is in the range (0, 1.0], use n * number of features. When n is in the range (1, number of features), use n features. (default = "auto")

These various settings are based on the following references: - log2: tested in Breiman (2001) - sqrt: recommended by Breiman manual for random forests - The defaults of sqrt (classification) and onethird (regression) match the R randomForest package.

Specified by:

featureSubsetStrategy in interface TreeEnsembleParams

Returns:

(undocumented)

See Also:

• Breiman (2001)
• Breiman manual for random forests

leafCol

public final Param<String> leafCol()

Description copied from interface: DecisionTreeParams

Leaf indices column name. Predicted leaf index of each instance in each tree by preorder. (default = "")

Specified by:

leafCol in interface DecisionTreeParams

Returns:

(undocumented)

maxDepth

public final IntParam maxDepth()

Description copied from interface: DecisionTreeParams

Maximum depth of the tree (nonnegative). E.g., depth 0 means 1 leaf node; depth 1 means 1 internal node + 2 leaf nodes. (default = 5)

Specified by:

maxDepth in interface DecisionTreeParams

Returns:

(undocumented)

maxBins

public final IntParam maxBins()

Description copied from interface: DecisionTreeParams

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 at least 2 and at least number of categories in any categorical feature. (default = 32)

Specified by:

maxBins in interface DecisionTreeParams

Returns:

(undocumented)

minInstancesPerNode

public final IntParam minInstancesPerNode()

Description copied from interface: DecisionTreeParams

Minimum number of instances each child must have after split. If a split causes the left or right child to have fewer than minInstancesPerNode, the split will be discarded as invalid. Must be at least 1. (default = 1)

Specified by:

minInstancesPerNode in interface DecisionTreeParams

Returns:

(undocumented)

minWeightFractionPerNode

public final DoubleParam minWeightFractionPerNode()

Description copied from interface: DecisionTreeParams

Minimum fraction of the weighted sample count that each child must have after split. If a split causes the fraction of the total weight in the left or right child to be less than minWeightFractionPerNode, the split will be discarded as invalid. Should be in the interval [0.0, 0.5). (default = 0.0)

Specified by:

minWeightFractionPerNode in interface DecisionTreeParams

Returns:

(undocumented)

minInfoGain

public final DoubleParam minInfoGain()

Description copied from interface: DecisionTreeParams

Minimum information gain for a split to be considered at a tree node. Should be at least 0.0. (default = 0.0)

Specified by:

minInfoGain in interface DecisionTreeParams

Returns:

(undocumented)

maxMemoryInMB

public final IntParam maxMemoryInMB()

Description copied from interface: DecisionTreeParams

Maximum memory in MB allocated to histogram aggregation. If too small, then 1 node will be split per iteration, and its aggregates may exceed this size. (default = 256 MB)

Specified by:

maxMemoryInMB in interface DecisionTreeParams

Returns:

(undocumented)

cacheNodeIds

public final BooleanParam cacheNodeIds()

Description copied from interface: DecisionTreeParams

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. (default = false)

Specified by:

cacheNodeIds in interface DecisionTreeParams

Returns:

(undocumented)

weightCol

public final Param<String> weightCol()

Description copied from interface: HasWeightCol

Param for weight column name. If this is not set or empty, we treat all instance weights as 1.0.

Specified by:

weightCol in interface HasWeightCol

Returns:

(undocumented)

seed

public final LongParam seed()

Description copied from interface: HasSeed

Param for random seed.

Specified by:

seed in interface HasSeed

Returns:

(undocumented)

checkpointInterval

public final IntParam checkpointInterval()

Description copied from interface: HasCheckpointInterval

Param for set checkpoint interval (&gt;= 1) or disable checkpoint (-1). E.g. 10 means that the cache will get checkpointed every 10 iterations. Note: this setting will be ignored if the checkpoint directory is not set in the SparkContext.

Specified by:

checkpointInterval in interface HasCheckpointInterval

Returns:

(undocumented)

uid

public String uid()

Description copied from interface: Identifiable

An immutable unique ID for the object and its derivatives.

Specified by:

uid in interface Identifiable

Returns:

(undocumented)

numFeatures

public int numFeatures()

Description copied from class: PredictionModel

Returns the number of features the model was trained on. If unknown, returns -1

Overrides:

numFeatures in class PredictionModel<Vector,RandomForestClassificationModel>

numClasses

public int numClasses()

Description copied from class: ClassificationModel

Number of classes (values which the label can take).

Specified by:

numClasses in class ClassificationModel<Vector,RandomForestClassificationModel>

estimatedSize

public long estimatedSize()

trees

public DecisionTreeClassificationModel[] trees()

Description copied from interface: TreeEnsembleModel

Trees in this ensemble. Warning: These have null parent Estimators.

Specified by:

trees in interface TreeEnsembleModel<DecisionTreeClassificationModel>

treeWeights

public double[] treeWeights()

Description copied from interface: TreeEnsembleModel

Weights for each tree, zippable with TreeEnsembleModel.trees()

Specified by:

treeWeights in interface TreeEnsembleModel<DecisionTreeClassificationModel>

summary

public RandomForestClassificationTrainingSummary summary()

Gets summary of model on training set. An exception is thrown if hasSummary is false.

Specified by:

summary in interface HasTrainingSummary<RandomForestClassificationTrainingSummary>

Returns:

(undocumented)

binarySummary

public BinaryRandomForestClassificationTrainingSummary binarySummary()

Gets summary of model on training set. An exception is thrown if hasSummary is false or it is a multiclass model.

Returns:

(undocumented)

evaluate

public RandomForestClassificationSummary evaluate(Dataset<?> dataset)

Evaluates the model on a test dataset.

Parameters:

dataset - Test dataset to evaluate model on.

Returns:

(undocumented)

transformSchema

public StructType transformSchema(StructType schema)

Description copied from class: PipelineStage

Check transform validity and derive the output schema from the input schema.

We check validity for interactions between parameters during transformSchema and raise an exception if any parameter value is invalid. Parameter value checks which do not depend on other parameters are handled by Param.validate().

Typical implementation should first conduct verification on schema change and parameter validity, including complex parameter interaction checks.

Overrides:

transformSchema in class ProbabilisticClassificationModel<Vector,RandomForestClassificationModel>

Parameters:

schema - (undocumented)

Returns:

(undocumented)

transform

public Dataset<Row> transform(Dataset<?> dataset)

Description copied from class: ProbabilisticClassificationModel

Transforms dataset by reading from PredictionModel.featuresCol(), and appending new columns as specified by parameters: - predicted labels as PredictionModel.predictionCol() of type Double - raw predictions (confidences) as ClassificationModel.rawPredictionCol() of type Vector - probability of each class as ProbabilisticClassificationModel.probabilityCol() of type Vector.

Overrides:

transform in class ProbabilisticClassificationModel<Vector,RandomForestClassificationModel>

Parameters:

dataset - input dataset

Returns:

transformed dataset

predictRaw

public Vector predictRaw(Vector features)

Description copied from class: ClassificationModel

Raw prediction for each possible label. The meaning of a "raw" prediction may vary between algorithms, but it intuitively gives a measure of confidence in each possible label (where larger = more confident). This internal method is used to implement transform() and output ClassificationModel.rawPredictionCol().

Specified by:

predictRaw in class ClassificationModel<Vector,RandomForestClassificationModel>

Parameters:

features - (undocumented)

Returns:

vector where element i is the raw prediction for label i. This raw prediction may be any real number, where a larger value indicates greater confidence for that label.

copy

public RandomForestClassificationModel copy(ParamMap extra)

Description copied from interface: Params

Creates a copy of this instance with the same UID and some extra params. Subclasses should implement this method and set the return type properly. See defaultCopy().

Specified by:

copy in interface Params

Specified by:

copy in class Model<RandomForestClassificationModel>

Parameters:

extra - (undocumented)

Returns:

(undocumented)

toString

public String toString()

Description copied from interface: TreeEnsembleModel

Summary of the model

Specified by:

toString in interface Identifiable

Specified by:

toString in interface TreeEnsembleModel<DecisionTreeClassificationModel>

Overrides:

toString in class Object

featureImportances

public Vector featureImportances()

write

public MLWriter write()

Description copied from interface: MLWritable

Returns an MLWriter instance for this ML instance.

Specified by:

write in interface MLWritable

Returns:

(undocumented)