Github user jkbradley commented on a diff in the pull request:
https://github.com/apache/spark/pull/3099#discussion_r20111111
--- Diff: mllib/src/main/scala/org/apache/spark/ml/Pipeline.scala ---
@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.ml
+
+import scala.collection.mutable.ListBuffer
+
+import org.apache.spark.Logging
+import org.apache.spark.ml.param.{Param, ParamMap}
+import org.apache.spark.sql.{SchemaRDD, StructType}
+
+/**
+ * A stage in a pipeline, either an Estimator or an Transformer.
+ */
+abstract class PipelineStage extends Serializable with Logging {
+
+ /**
+ * Derives the output schema from the input schema and parameters.
+ */
+ def transform(schema: StructType, paramMap: ParamMap): StructType
+
+ /**
+ * Drives the output schema from the input schema and parameters,
optionally with logging.
+ */
+ protected def transform(schema: StructType, paramMap: ParamMap, logging:
Boolean): StructType = {
+ if (logging) {
+ logDebug(s"Input schema: ${schema.json}")
+ }
+ val outputSchema = transform(schema, paramMap)
+ if (logging) {
+ logDebug(s"Expected output schema: ${outputSchema.json}")
+ }
+ outputSchema
+ }
+}
+
+/**
+ * A simple pipeline, which acts as an estimator.
+ */
+class Pipeline extends Estimator[PipelineModel] {
+
+ val stages: Param[Array[PipelineStage]] = new Param(this, "stages",
"stages of the pipeline")
+ def setStages(value: Array[PipelineStage]): this.type = { set(stages,
value); this }
+ def getStages: Array[PipelineStage] = get(stages)
+
+ override def fit(dataset: SchemaRDD, paramMap: ParamMap): PipelineModel
= {
+ transform(dataset.schema, paramMap, logging = true)
+ val map = this.paramMap ++ paramMap
+ val theStages = map(stages)
+ // Search for the last estimator.
+ var lastIndexOfEstimator = -1
+ theStages.view.zipWithIndex.foreach { case (stage, index) =>
+ stage match {
+ case _: Estimator[_] =>
+ lastIndexOfEstimator = index
+ case _ =>
+ }
+ }
+ var curDataset = dataset
+ val transformers = ListBuffer.empty[Transformer]
+ theStages.view.zipWithIndex.foreach { case (stage, index) =>
+ stage match {
+ case estimator: Estimator[_] =>
+ val transformer = estimator.fit(curDataset, paramMap)
+ if (index < lastIndexOfEstimator) {
+ curDataset = transformer.transform(curDataset, paramMap)
+ }
+ transformers += transformer
+ case transformer: Transformer =>
+ if (index < lastIndexOfEstimator) {
+ curDataset = transformer.transform(curDataset, paramMap)
+ }
+ transformers += transformer
+ case _ =>
+ throw new IllegalArgumentException
+ }
+ }
+
+ new PipelineModel(this, map, transformers.toArray)
+ }
+
+ override def transform(schema: StructType, paramMap: ParamMap):
StructType = {
+ val map = this.paramMap ++ paramMap
+ map(stages).foldLeft(schema)((cur, stage) => stage.transform(cur,
paramMap))
+ }
+}
+
+/**
+ * Represents a compiled pipeline.
+ */
+class PipelineModel(
+ override val parent: Pipeline,
+ override val fittingParamMap: ParamMap,
+ val transformers: Array[Transformer]) extends Model[PipelineModel]
with Logging {
+
+ /**
+ * Gets the model produced by the input estimator. Throws an
NoSuchElementException is the input
+ * estimator does not exist in the pipeline.
+ */
+ def getModel[M <: Model[M]](estimator: Estimator[M]): M = {
+ val matched = transformers.filter {
+ case m: Model[_] => m.parent.eq(estimator)
+ case _ => false
+ }
+ if (matched.isEmpty) {
+ throw new NoSuchElementException(s"Cannot find estimator $estimator
from the pipeline.")
+ } else if (matched.size > 1) {
+ throw new IllegalStateException(s"Cannot have duplicate estimators
in the sample pipeline.")
+ } else {
+ matched.head.asInstanceOf[M]
+ }
+ }
+
+ override def transform(dataset: SchemaRDD, paramMap: ParamMap):
SchemaRDD = {
+ transform(dataset.schema, paramMap, logging = true)
+ transformers.foldLeft(dataset)((cur, transformer) =>
transformer.transform(cur, paramMap))
+ }
+
+ override def transform(schema: StructType, paramMap: ParamMap):
StructType = {
--- End diff --
Should this merge fittingParamMap with paramMap?
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
