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diff --git a/docs/mllib-migration-guides.md b/docs/mllib-migration-guides.md index 970c6697f4..ea6f93fcf6 100644 --- a/docs/mllib-migration-guides.md +++ b/docs/mllib-migration-guides.md @@ -1,159 +1,9 @@ --- layout: global -title: Old Migration Guides - spark.mllib -displayTitle: Old Migration Guides - spark.mllib -description: MLlib migration guides from before Spark SPARK_VERSION_SHORT +title: Old Migration Guides - MLlib +displayTitle: Old Migration Guides - MLlib --- -The migration guide for the current Spark version is kept on the [MLlib Programming Guide main page](mllib-guide.html#migration-guide). - -## From 1.5 to 1.6 - -There are no breaking API changes in the `spark.mllib` or `spark.ml` packages, but there are -deprecations and changes of behavior. - -Deprecations: - -* [SPARK-11358](https://issues.apache.org/jira/browse/SPARK-11358): - In `spark.mllib.clustering.KMeans`, the `runs` parameter has been deprecated. -* [SPARK-10592](https://issues.apache.org/jira/browse/SPARK-10592): - In `spark.ml.classification.LogisticRegressionModel` and - `spark.ml.regression.LinearRegressionModel`, the `weights` field has been deprecated in favor of - the new name `coefficients`. This helps disambiguate from instance (row) "weights" given to - algorithms. - -Changes of behavior: - -* [SPARK-7770](https://issues.apache.org/jira/browse/SPARK-7770): - `spark.mllib.tree.GradientBoostedTrees`: `validationTol` has changed semantics in 1.6. - Previously, it was a threshold for absolute change in error. Now, it resembles the behavior of - `GradientDescent`'s `convergenceTol`: For large errors, it uses relative error (relative to the - previous error); for small errors (`< 0.01`), it uses absolute error. -* [SPARK-11069](https://issues.apache.org/jira/browse/SPARK-11069): - `spark.ml.feature.RegexTokenizer`: Previously, it did not convert strings to lowercase before - tokenizing. Now, it converts to lowercase by default, with an option not to. This matches the - behavior of the simpler `Tokenizer` transformer. - -## From 1.4 to 1.5 - -In the `spark.mllib` package, there are no breaking API changes but several behavior changes: - -* [SPARK-9005](https://issues.apache.org/jira/browse/SPARK-9005): - `RegressionMetrics.explainedVariance` returns the average regression sum of squares. -* [SPARK-8600](https://issues.apache.org/jira/browse/SPARK-8600): `NaiveBayesModel.labels` become - sorted. -* [SPARK-3382](https://issues.apache.org/jira/browse/SPARK-3382): `GradientDescent` has a default - convergence tolerance `1e-3`, and hence iterations might end earlier than 1.4. - -In the `spark.ml` package, there exists one breaking API change and one behavior change: - -* [SPARK-9268](https://issues.apache.org/jira/browse/SPARK-9268): Java's varargs support is removed - from `Params.setDefault` due to a - [Scala compiler bug](https://issues.scala-lang.org/browse/SI-9013). -* [SPARK-10097](https://issues.apache.org/jira/browse/SPARK-10097): `Evaluator.isLargerBetter` is - added to indicate metric ordering. Metrics like RMSE no longer flip signs as in 1.4. - -## From 1.3 to 1.4 - -In the `spark.mllib` package, there were several breaking changes, but all in `DeveloperApi` or `Experimental` APIs: - -* Gradient-Boosted Trees - * *(Breaking change)* The signature of the [`Loss.gradient`](api/scala/index.html#org.apache.spark.mllib.tree.loss.Loss) method was changed. This is only an issues for users who wrote their own losses for GBTs. - * *(Breaking change)* The `apply` and `copy` methods for the case class [`BoostingStrategy`](api/scala/index.html#org.apache.spark.mllib.tree.configuration.BoostingStrategy) have been changed because of a modification to the case class fields. This could be an issue for users who use `BoostingStrategy` to set GBT parameters. -* *(Breaking change)* The return value of [`LDA.run`](api/scala/index.html#org.apache.spark.mllib.clustering.LDA) has changed. It now returns an abstract class `LDAModel` instead of the concrete class `DistributedLDAModel`. The object of type `LDAModel` can still be cast to the appropriate concrete type, which depends on the optimization algorithm. - -In the `spark.ml` package, several major API changes occurred, including: - -* `Param` and other APIs for specifying parameters -* `uid` unique IDs for Pipeline components -* Reorganization of certain classes - -Since the `spark.ml` API was an alpha component in Spark 1.3, we do not list all changes here. -However, since 1.4 `spark.ml` is no longer an alpha component, we will provide details on any API -changes for future releases. - -## From 1.2 to 1.3 - -In the `spark.mllib` package, there were several breaking changes. The first change (in `ALS`) is the only one in a component not marked as Alpha or Experimental. - -* *(Breaking change)* In [`ALS`](api/scala/index.html#org.apache.spark.mllib.recommendation.ALS), the extraneous method `solveLeastSquares` has been removed. The `DeveloperApi` method `analyzeBlocks` was also removed. -* *(Breaking change)* [`StandardScalerModel`](api/scala/index.html#org.apache.spark.mllib.feature.StandardScalerModel) remains an Alpha component. In it, the `variance` method has been replaced with the `std` method. To compute the column variance values returned by the original `variance` method, simply square the standard deviation values returned by `std`. -* *(Breaking change)* [`StreamingLinearRegressionWithSGD`](api/scala/index.html#org.apache.spark.mllib.regression.StreamingLinearRegressionWithSGD) remains an Experimental component. In it, there were two changes: - * The constructor taking arguments was removed in favor of a builder pattern using the default constructor plus parameter setter methods. - * Variable `model` is no longer public. -* *(Breaking change)* [`DecisionTree`](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree) remains an Experimental component. In it and its associated classes, there were several changes: - * In `DecisionTree`, the deprecated class method `train` has been removed. (The object/static `train` methods remain.) - * In `Strategy`, the `checkpointDir` parameter has been removed. Checkpointing is still supported, but the checkpoint directory must be set before calling tree and tree ensemble training. -* `PythonMLlibAPI` (the interface between Scala/Java and Python for MLlib) was a public API but is now private, declared `private[python]`. This was never meant for external use. -* In linear regression (including Lasso and ridge regression), the squared loss is now divided by 2. - So in order to produce the same result as in 1.2, the regularization parameter needs to be divided by 2 and the step size needs to be multiplied by 2. - -In the `spark.ml` package, the main API changes are from Spark SQL. We list the most important changes here: - -* The old [SchemaRDD](http://spark.apache.org/docs/1.2.1/api/scala/index.html#org.apache.spark.sql.SchemaRDD) has been replaced with [DataFrame](api/scala/index.html#org.apache.spark.sql.DataFrame) with a somewhat modified API. All algorithms in Spark ML which used to use SchemaRDD now use DataFrame. -* In Spark 1.2, we used implicit conversions from `RDD`s of `LabeledPoint` into `SchemaRDD`s by calling `import sqlContext._` where `sqlContext` was an instance of `SQLContext`. These implicits have been moved, so we now call `import sqlContext.implicits._`. -* Java APIs for SQL have also changed accordingly. Please see the examples above and the [Spark SQL Programming Guide](sql-programming-guide.html) for details. - -Other changes were in `LogisticRegression`: - -* The `scoreCol` output column (with default value "score") was renamed to be `probabilityCol` (with default value "probability"). The type was originally `Double` (for the probability of class 1.0), but it is now `Vector` (for the probability of each class, to support multiclass classification in the future). -* In Spark 1.2, `LogisticRegressionModel` did not include an intercept. In Spark 1.3, it includes an intercept; however, it will always be 0.0 since it uses the default settings for [spark.mllib.LogisticRegressionWithLBFGS](api/scala/index.html#org.apache.spark.mllib.classification.LogisticRegressionWithLBFGS). The option to use an intercept will be added in the future. - -## From 1.1 to 1.2 - -The only API changes in MLlib v1.2 are in -[`DecisionTree`](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree), -which continues to be an experimental API in MLlib 1.2: - -1. *(Breaking change)* The Scala API for classification takes a named argument specifying the number -of classes. In MLlib v1.1, this argument was called `numClasses` in Python and -`numClassesForClassification` in Scala. In MLlib v1.2, the names are both set to `numClasses`. -This `numClasses` parameter is specified either via -[`Strategy`](api/scala/index.html#org.apache.spark.mllib.tree.configuration.Strategy) -or via [`DecisionTree`](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree) -static `trainClassifier` and `trainRegressor` methods. - -2. *(Breaking change)* The API for -[`Node`](api/scala/index.html#org.apache.spark.mllib.tree.model.Node) has changed. -This should generally not affect user code, unless the user manually constructs decision trees -(instead of using the `trainClassifier` or `trainRegressor` methods). -The tree `Node` now includes more information, including the probability of the predicted label -(for classification). - -3. Printing methods' output has changed. The `toString` (Scala/Java) and `__repr__` (Python) methods used to print the full model; they now print a summary. For the full model, use `toDebugString`. - -Examples in the Spark distribution and examples in the -[Decision Trees Guide](mllib-decision-tree.html#examples) have been updated accordingly. - -## From 1.0 to 1.1 - -The only API changes in MLlib v1.1 are in -[`DecisionTree`](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree), -which continues to be an experimental API in MLlib 1.1: - -1. *(Breaking change)* The meaning of tree depth has been changed by 1 in order to match -the implementations of trees in -[scikit-learn](http://scikit-learn.org/stable/modules/classes.html#module-sklearn.tree) -and in [rpart](http://cran.r-project.org/web/packages/rpart/index.html). -In MLlib v1.0, a depth-1 tree had 1 leaf node, and a depth-2 tree had 1 root node and 2 leaf nodes. -In MLlib v1.1, a depth-0 tree has 1 leaf node, and a depth-1 tree has 1 root node and 2 leaf nodes. -This depth is specified by the `maxDepth` parameter in -[`Strategy`](api/scala/index.html#org.apache.spark.mllib.tree.configuration.Strategy) -or via [`DecisionTree`](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree) -static `trainClassifier` and `trainRegressor` methods. - -2. *(Non-breaking change)* We recommend using the newly added `trainClassifier` and `trainRegressor` -methods to build a [`DecisionTree`](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree), -rather than using the old parameter class `Strategy`. These new training methods explicitly -separate classification and regression, and they replace specialized parameter types with -simple `String` types. - -Examples of the new, recommended `trainClassifier` and `trainRegressor` are given in the -[Decision Trees Guide](mllib-decision-tree.html#examples). - -## From 0.9 to 1.0 - -In MLlib v1.0, we support both dense and sparse input in a unified way, which introduces a few -breaking changes. If your data is sparse, please store it in a sparse format instead of dense to -take advantage of sparsity in both storage and computation. Details are described below. +The migration guide for the current Spark version is kept on the [MLlib Guide main page](ml-guide.html#migration-guide). +Past migration guides are now stored at [ml-migration-guides.html](ml-migration-guides.html). |