Spark ML – Model Persistence — ml-persistence • sparklyr

Save/load Spark ML objects

Usage

ml_save(x, path, overwrite = FALSE, ...)

# S3 method for class 'ml_model'
ml_save(
  x,
  path,
  overwrite = FALSE,
  type = c("pipeline_model", "pipeline"),
  ...
)

ml_load(sc, path)

Arguments

x: A ML object, which could be a ml_pipeline_stage or a ml_model
path: The path where the object is to be serialized/deserialized.
overwrite: Whether to overwrite the existing path, defaults to FALSE.
...: Optional arguments; currently unused.
type: Whether to save the pipeline model or the pipeline.
sc: A Spark connection.

Value

ml_save() serializes a Spark object into a format that can be read back into sparklyr or by the Scala or PySpark APIs. When called on ml_model objects, i.e. those that were created via the tbl_spark - formula signature, the associated pipeline model is serialized. In other words, the saved model contains both the data processing (RFormulaModel) stage and the machine learning stage.

ml_load() reads a saved Spark object into sparklyr. It calls the correct Scala load method based on parsing the saved metadata. Note that a PipelineModel object saved from a sparklyr ml_model via ml_save() will be read back in as an ml_pipeline_model, rather than the ml_model object.