This is part (1a) of the updates from the design doc in [https://docs.google.com/document/d/1BH9el33kBX8JiDdgUJXdLW14CA2qhTCWIG46eXZVoJs]
**UPDATE**: Most of the APIs are being kept private[spark] to allow further discussion. Here is a list of changes which are public:
* new output columns: rawPrediction, probabilities
* The “score” column is now called “rawPrediction”
* Classifiers now provide numClasses
* Params.get and .set are now protected instead of private[ml].
* ParamMap now has a size method.
* new classes: LinearRegression, LinearRegressionModel
* LogisticRegression now has an intercept.
### Sketch of APIs (most of which are private[spark] for now)
Abstract classes for learning algorithms (+ corresponding Model abstractions):
* Classifier (+ ClassificationModel)
* ProbabilisticClassifier (+ ProbabilisticClassificationModel)
* Regressor (+ RegressionModel)
* Predictor (+ PredictionModel)
* *For all of these*:
* There is no strongly typed training-time API.
* There is a strongly typed test-time (prediction) API which helps developers implement new algorithms.
Concrete classes: learning algorithms
* LinearRegression
* LogisticRegression (updated to use new abstract classes)
* Also, removed "score" in favor of "probability" output column. Changed BinaryClassificationEvaluator to match. (SPARK-5031)
Other updates:
* params.scala: Changed Params.set/get to be protected instead of private[ml]
* This was needed for the example of defining a class from outside of the MLlib namespace.
* VectorUDT: Will later change from private[spark] to public.
* This is needed for outside users to write their own validateAndTransformSchema() methods using vectors.
* Also, added equals() method.f
* SPARK-4942 : ML Transformers should allow output cols to be turned on,off
* Update validateAndTransformSchema
* Update transform
* (Updated examples, test suites according to other changes)
New examples:
* DeveloperApiExample.scala (example of defining algorithm from outside of the MLlib namespace)
* Added Java version too
Test Suites:
* LinearRegressionSuite
* LogisticRegressionSuite
* + Java versions of above suites
CC: mengxr etrain shivaram
Author: Joseph K. Bradley <joseph@databricks.com>
Closes#3637 from jkbradley/ml-api-part1 and squashes the following commits:
405bfb8 [Joseph K. Bradley] Last edits based on code review. Small cleanups
fec348a [Joseph K. Bradley] Added JavaDeveloperApiExample.java and fixed other issues: Made developer API private[spark] for now. Added constructors Java can understand to specialized Param types.
8316d5e [Joseph K. Bradley] fixes after rebasing on master
fc62406 [Joseph K. Bradley] fixed test suites after last commit
bcb9549 [Joseph K. Bradley] Fixed issues after rebasing from master (after move from SchemaRDD to DataFrame)
9872424 [Joseph K. Bradley] fixed JavaLinearRegressionSuite.java Java sql api
f542997 [Joseph K. Bradley] Added MIMA excludes for VectorUDT (now public), and added DeveloperApi annotation to it
216d199 [Joseph K. Bradley] fixed after sql datatypes PR got merged
f549e34 [Joseph K. Bradley] Updates based on code review. Major ones are: * Created weakly typed Predictor.train() method which is called by fit() so that developers do not have to call schema validation or copy parameters. * Made Predictor.featuresDataType have a default value of VectorUDT. * NOTE: This could be dangerous since the FeaturesType type parameter cannot have a default value.
343e7bd [Joseph K. Bradley] added blanket mima exclude for ml package
82f340b [Joseph K. Bradley] Fixed bug in LogisticRegression (introduced in this PR). Fixed Java suites
0a16da9 [Joseph K. Bradley] Fixed Linear/Logistic RegressionSuites
c3c8da5 [Joseph K. Bradley] small cleanup
934f97b [Joseph K. Bradley] Fixed bugs from previous commit.
1c61723 [Joseph K. Bradley] * Made ProbabilisticClassificationModel into a subclass of ClassificationModel. Also introduced ProbabilisticClassifier. * This was to support output column “probabilityCol” in transform().
4e2f711 [Joseph K. Bradley] rat fix
bc654e1 [Joseph K. Bradley] Added spark.ml LinearRegressionSuite
8d13233 [Joseph K. Bradley] Added methods: * Classifier: batch predictRaw() * Predictor: train() without paramMap ProbabilisticClassificationModel.predictProbabilities() * Java versions of all above batch methods + others
1680905 [Joseph K. Bradley] Added JavaLabeledPointSuite.java for spark.ml, and added constructor to LabeledPoint which defaults weight to 1.0
adbe50a [Joseph K. Bradley] * fixed LinearRegression train() to use embedded paramMap * added Predictor.predict(RDD[Vector]) method * updated Linear/LogisticRegressionSuites
58802e3 [Joseph K. Bradley] added train() to Predictor subclasses which does not take a ParamMap.
57d54ab [Joseph K. Bradley] * Changed semantics of Predictor.train() to merge the given paramMap with the embedded paramMap. * remove threshold_internal from logreg * Added Predictor.copy() * Extended LogisticRegressionSuite
e433872 [Joseph K. Bradley] Updated docs. Added LabeledPointSuite to spark.ml
54b7b31 [Joseph K. Bradley] Fixed issue with logreg threshold being set correctly
0617d61 [Joseph K. Bradley] Fixed bug from last commit (sorting paramMap by parameter names in toString). Fixed bug in persisting logreg data. Added threshold_internal to logreg for faster test-time prediction (avoiding map lookup).
601e792 [Joseph K. Bradley] Modified ParamMap to sort parameters in toString. Cleaned up classes in class hierarchy, before implementing tests and examples.
d705e87 [Joseph K. Bradley] Added LinearRegression and Regressor back from ml-api branch
52f4fde [Joseph K. Bradley] removing everything except for simple class hierarchy for classification
d35bb5d [Joseph K. Bradley] fixed compilation issues, but have not added tests yet
bfade12 [Joseph K. Bradley] Added lots of classes for new ML API:
dc0c4490a1