[DLlib] GBT CriteoClickLogsDataset example (#5723)

* init gbt class

* remove something unimportant

* add readme

* change xgb to gbt

* use overwrite to save

* add text to fix message=Header does not match expected text line=1

scala/dllib/src/main/scala/com/intel/analytics/bigdl/dllib/example/nnframes/gbt/README.md

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+# Prepare
+
+## Environment
+- Spark 2.4 or Spark 3.1
+- BigDL 2.0 
+
+## Data Prepare
+
+### BigDL nightly build
+
+You can download [here](https://bigdl.readthedocs.io/en/latest/doc/release.html).
+For spark 2.4 you need `bigdl-dllib-spark_2.4.6-0.14.0-build_time-jar-with-dependencies.jar` or `bigdl-dllib-spark_3.1.2-0.14.0-build_time-jar-with-dependencies.jar` for spark 3.1 . 
+
+# GBT On Criteo-click-logs-dataset
+## Download data
+You can download the criteo-1tb-click-logs-dataset from [here](https://ailab.criteo.com/download-criteo-1tb-click-logs-dataset/). Then unzip the files you downloaded and Split 1g data to a folder.
+
+## Train
+```
+spark-submit \
+  --master local[4] \
+  --conf spark.task.cpus=4 \
+  --class com.intel.analytics.bigdl.dllib.example.nnframes.gbt.gbtClassifierTrainingExampleOnCriteoClickLogsDataset \
+  --num-executors 2 \
+  --executor-cores 4 \
+  --executor-memory 4G \
+  --driver-memory 10G \
+  /path/to/bigdl-dllib-spark_3.1.2-0.14.0-SNAPSHOT-jar-with-dependencies.jar \
+  -i /path/to/preprocessed-data/saved -s /path/to/model/saved -I max_Iter -d max_depth
+```
+
+parameters:
+- input_path: String. Path to criteo-click-logs-dataset.
+- modelsave_path: String. Path to model to be saved.
+- max_iter: Int. Training max iter.
+- max_depth: Int. Tree max depth.
+
+The tree of folder `/path/to/model/saved` is:
+```
+/path/to/model/saved
+├── data
+└── metadata
+    ├── part-00000
+    └── _SUCCESS
+```

scala/dllib/src/main/scala/com/intel/analytics/bigdl/dllib/example/nnframes/gbt/gbtClassifierTrainingExampleOnCriteoClickLogsDataset.scala

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+/*
+ * Copyright 2016 The BigDL Authors.
+ *
+ * Licensed 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 com.intel.analytics.bigdl.dllib.example.nnframes.gbt
+
+import com.intel.analytics.bigdl.dllib.NNContext
+import org.apache.spark.ml.classification.GBTClassifier
+import org.apache.spark.ml.feature.{StringIndexer, VectorAssembler}
+import org.apache.spark.sql.types.{LongType, StructField, StructType}
+import org.apache.spark.sql.{Row, SQLContext}
+import org.slf4j.{Logger, LoggerFactory}
+import scopt.OptionParser
+
+
+class Task extends Serializable {
+
+  val default_missing_value = "-999"
+
+  def rowToLibsvm(row: Row): String = {
+    0 until row.length flatMap {
+      case 0 => Some(row(0).toString)
+      case i if row(i) == null => Some(default_missing_value)
+      case i => Some((if (i < 14) row(i)
+      else java.lang.Long.parseLong(row(i).toString, 16)).toString)
+    } mkString " "
+  }
+}
+
+case class Params(
+                   trainingDataPath: String = "/host/data",
+                   modelSavePath: String = "/host/data/model",
+                   maxIter: Int = 100,
+                   maxDepth: Int = 2
+                 )
+
+object gbtClassifierTrainingExampleOnCriteoClickLogsDataset {
+
+  val feature_nums = 39
+
+  def main(args: Array[String]): Unit = {
+
+    val log: Logger = LoggerFactory.getLogger(this.getClass)
+
+
+    // parse params and set value
+
+    val params = parser.parse(args, new Params).get
+    val trainingDataPath = params.trainingDataPath // path to data
+    val modelSavePath = params.modelSavePath // save model to this path
+    val maxIter = params.maxIter //  train max Iter
+    val maxDepth = params.maxDepth // tree max depth
+
+    val sc = NNContext.initNNContext()
+    val spark = SQLContext.getOrCreate(sc)
+
+    val task = new Task()
+
+    val tStart = System.nanoTime()
+    // read csv files to dataframe
+    var df = spark.read.option("header", "false").
+      option("inferSchema", "true").option("delimiter", "\t").csv(trainingDataPath)
+
+    val tBeforePreprocess = System.nanoTime()
+    var elapsed = (tBeforePreprocess - tStart) / 1000000000.0f // second
+    log.info("--reading data time is " + elapsed + " s")
+    // preprocess data
+    val processedRdd = df.rdd.map(task.rowToLibsvm)
+
+    // declare schema
+    var structFieldArray = new Array[StructField](feature_nums + 1)
+    for (i <- 0 to feature_nums) {
+      structFieldArray(i) = StructField("_c" + i.toString, LongType, true)
+    }
+    var schema = new StructType(structFieldArray)
+
+    // convert RDD to RDD[Row]
+    val rowRDD = processedRdd.map(_.split(" ")).map(row => Row.fromSeq(
+      for {
+        i <- 0 to feature_nums
+      } yield {
+        row(i).toLong
+      }
+    ))
+    // RDD[Row] to Dataframe
+    df = spark.createDataFrame(rowRDD, schema)
+
+
+    val stringIndexer = new StringIndexer()
+      .setInputCol("_c0")
+      .setOutputCol("classIndex")
+      .fit(df)
+    val labelTransformed = stringIndexer.transform(df).drop("_c0")
+
+    var inputCols = new Array[String](feature_nums)
+    for (i <- 0 to feature_nums - 1) {
+      inputCols(i) = "_c" + (i + 1).toString
+    }
+
+    val vectorAssembler = new VectorAssembler().
+      setInputCols(inputCols).
+      setOutputCol("features")
+
+    val gbtInput = vectorAssembler.transform(labelTransformed).select("features", "classIndex")
+    // randomly split dataset to (train, eval1, eval2, test) in proportion 6:2:1:1
+    val Array(train, eval1, eval2, test) = gbtInput.randomSplit(Array(0.6, 0.2, 0.1, 0.1))
+
+    train.cache().count()
+    eval1.cache().count()
+    eval2.cache().count()
+
+    val tBeforeTraining = System.nanoTime()
+    elapsed = (tBeforeTraining - tBeforePreprocess) / 1000000000.0f // second
+    log.info("--preprocess time is " + elapsed + " s")
+    // use scala tracker
+    //    val gbtParam = Map("tracker_conf" -> TrackerConf(0L, "scala"),
+    //      "eval_sets" -> Map("eval1" -> eval1, "eval2" -> eval2)
+    //    )
+
+    // Train a GBT model.
+    val gbtClassifier = new GBTClassifier()
+    gbtClassifier.setFeaturesCol("features")
+    gbtClassifier.setLabelCol("classIndex")
+    gbtClassifier.setMaxDepth(maxDepth)
+    gbtClassifier.setMaxIter(maxIter)
+    gbtClassifier.setFeatureSubsetStrategy("auto")
+
+    // Train model. This also runs the indexer.
+    val gbtClassificationModel = gbtClassifier.fit(train)
+    val tAfterTraining = System.nanoTime()
+    elapsed = (tAfterTraining - tBeforeTraining) / 1000000000.0f // second
+    log.info("--training time is " + elapsed + " s")
+
+    gbtClassificationModel.write.overwrite().save(modelSavePath)
+
+    val tAfterSave = System.nanoTime()
+    elapsed = (tAfterSave - tAfterTraining) / 1000000000.0f // second
+    log.info("--model save time is " + elapsed + " s")
+    elapsed = (tAfterSave - tStart) / 1000000000.0f // second
+    log.info("--end-to-end time is " + elapsed + " s")
+    sc.stop()
+  }
+
+  val parser: OptionParser[Params] = new OptionParser[Params]("input gbt config") {
+    opt[String]('i', "trainingDataPath")
+      .text("trainingData Path")
+      .action((v, p) => p.copy(trainingDataPath = v))
+      .required()
+
+    opt[String]('s', "modelSavePath")
+      .text("savePath of model")
+      .action((v, p) => p.copy(modelSavePath = v))
+      .required()
+
+    opt[Int]('I', "maxIter")
+      .text("maxIter")
+      .action((v, p) => p.copy(maxIter = v))
+
+    opt[Int]('d', "maxDepth")
+      .text("maxDepth")
+      .action((v, p) => p.copy(maxDepth = v))
+
+  }
+}
+