examples/ml/JavaMaxAbsScalerExample.java

0001 /*
0002  * Licensed to the Apache Software Foundation (ASF) under one or more
0003  * contributor license agreements.  See the NOTICE file distributed with
0004  * this work for additional information regarding copyright ownership.
0005  * The ASF licenses this file to You under the Apache License, Version 2.0
0006  * (the "License"); you may not use this file except in compliance with
0007  * the License.  You may obtain a copy of the License at
0008  *
0009  *    http://www.apache.org/licenses/LICENSE-2.0
0010  *
0011  * Unless required by applicable law or agreed to in writing, software
0012  * distributed under the License is distributed on an "AS IS" BASIS,
0013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0014  * See the License for the specific language governing permissions and
0015  * limitations under the License.
0016  */
0017
0018 package org.apache.spark.examples.ml;
0019
0020 // $example on$
0021 import java.util.Arrays;
0022 import java.util.List;
0023
0024 import org.apache.spark.ml.feature.MaxAbsScaler;
0025 import org.apache.spark.ml.feature.MaxAbsScalerModel;
0026 import org.apache.spark.ml.linalg.Vectors;
0027 import org.apache.spark.ml.linalg.VectorUDT;
0028 import org.apache.spark.sql.Dataset;
0029 import org.apache.spark.sql.Row;
0030 import org.apache.spark.sql.RowFactory;
0031 import org.apache.spark.sql.types.DataTypes;
0032 import org.apache.spark.sql.types.Metadata;
0033 import org.apache.spark.sql.types.StructField;
0034 import org.apache.spark.sql.types.StructType;
0035 // $example off$
0036 import org.apache.spark.sql.SparkSession;
0037
0038 public class JavaMaxAbsScalerExample {
0039
0040   public static void main(String[] args) {
0041     SparkSession spark = SparkSession
0042       .builder()
0043       .appName("JavaMaxAbsScalerExample")
0044       .getOrCreate();
0045
0046     // $example on$
0047     List<Row> data = Arrays.asList(
0048         RowFactory.create(0, Vectors.dense(1.0, 0.1, -8.0)),
0049         RowFactory.create(1, Vectors.dense(2.0, 1.0, -4.0)),
0050         RowFactory.create(2, Vectors.dense(4.0, 10.0, 8.0))
0051     );
0052     StructType schema = new StructType(new StructField[]{
0053         new StructField("id", DataTypes.IntegerType, false, Metadata.empty()),
0054         new StructField("features", new VectorUDT(), false, Metadata.empty())
0055     });
0056     Dataset<Row> dataFrame = spark.createDataFrame(data, schema);
0057
0058     MaxAbsScaler scaler = new MaxAbsScaler()
0059       .setInputCol("features")
0060       .setOutputCol("scaledFeatures");
0061
0062     // Compute summary statistics and generate MaxAbsScalerModel
0063     MaxAbsScalerModel scalerModel = scaler.fit(dataFrame);
0064
0065     // rescale each feature to range [-1, 1].
0066     Dataset<Row> scaledData = scalerModel.transform(dataFrame);
0067     scaledData.select("features", "scaledFeatures").show();
0068     // $example off$
0069
0070     spark.stop();
0071   }
0072
0073 }