spark.randomForest {SparkR} | R Documentation |

`spark.randomForest`

fits a Random Forest Regression model or Classification model on
a SparkDataFrame. Users can call `summary`

to get a summary of the fitted Random Forest
model, `predict`

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

/`read.ml`

to
save/load fitted models.
For more details, see
Random Forest Regression and
Random Forest Classification

spark.randomForest(data, formula, ...) ## S4 method for signature 'SparkDataFrame,formula' spark.randomForest(data, formula, type = c("regression", "classification"), maxDepth = 5, maxBins = 32, numTrees = 20, impurity = NULL, featureSubsetStrategy = "auto", seed = NULL, subsamplingRate = 1, minInstancesPerNode = 1, minInfoGain = 0, checkpointInterval = 10, maxMemoryInMB = 256, cacheNodeIds = FALSE) ## S4 method for signature 'RandomForestRegressionModel' summary(object) ## S3 method for class 'summary.RandomForestRegressionModel' print(x, ...) ## S4 method for signature 'RandomForestClassificationModel' summary(object) ## S3 method for class 'summary.RandomForestClassificationModel' print(x, ...) ## S4 method for signature 'RandomForestRegressionModel' predict(object, newData) ## S4 method for signature 'RandomForestClassificationModel' predict(object, newData) ## S4 method for signature 'RandomForestRegressionModel,character' write.ml(object, path, overwrite = FALSE) ## S4 method for signature 'RandomForestClassificationModel,character' write.ml(object, path, overwrite = FALSE)

`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. |

`numTrees` |
Number of trees to train (>= 1). |

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

`featureSubsetStrategy` |
The number of features to consider for splits at each tree node. Supported options: "auto", "all", "onethird", "sqrt", "log2", (0.0-1.0], [1-n]. |

`seed` |
integer seed for random number generation. |

`subsamplingRate` |
Fraction of the training data used for learning each decision tree, in range (0, 1]. |

`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). |

`maxMemoryInMB` |
Maximum memory in MB 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. |

`object` |
A fitted Random Forest regression model or classification model. |

`x` |
summary object of Random Forest regression model or classification model
returned by |

`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. |

`spark.randomForest`

returns a fitted Random Forest 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), `maxDepth`

(max depth of trees),
`numTrees`

(number of trees), and `treeWeights`

(tree weights).

`predict`

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

spark.randomForest since 2.1.0

summary(RandomForestRegressionModel) since 2.1.0

print.summary.RandomForestRegressionModel since 2.1.0

summary(RandomForestClassificationModel) since 2.1.0

print.summary.RandomForestClassificationModel since 2.1.0

predict(RandomForestRegressionModel) since 2.1.0

predict(RandomForestClassificationModel) since 2.1.0

write.ml(RandomForestRegressionModel, character) since 2.1.0

write.ml(RandomForestClassificationModel, character) since 2.1.0

```
## Not run:
##D # fit a Random Forest Regression Model
##D df <- createDataFrame(longley)
##D model <- spark.randomForest(df, Employed ~ ., type = "regression", maxDepth = 5, maxBins = 16)
##D
##D # get the summary of the model
##D summary(model)
##D
##D # make predictions
##D predictions <- predict(model, df)
##D
##D # save and load the model
##D path <- "path/to/model"
##D write.ml(model, path)
##D savedModel <- read.ml(path)
##D summary(savedModel)
##D
##D # fit a Random Forest Classification Model
##D t <- as.data.frame(Titanic)
##D df <- createDataFrame(t)
##D model <- spark.randomForest(df, Survived ~ Freq + Age, "classification")
## End(Not run)
```

[Package *SparkR* version 2.2.0 Index]