yunfengzhou-hub commented on a change in pull request #32: URL: https://github.com/apache/flink-ml/pull/32#discussion_r755759161
########## File path: flink-ml-lib/src/main/java/org/apache/flink/ml/classification/naivebayes/NaiveBayes.java ########## @@ -0,0 +1,333 @@ +/* + * 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.flink.ml.classification.naivebayes; + +import org.apache.flink.api.common.functions.AggregateFunction; +import org.apache.flink.api.common.functions.FlatMapFunction; +import org.apache.flink.api.common.functions.MapFunction; +import org.apache.flink.api.common.functions.ReduceFunction; +import org.apache.flink.api.java.functions.KeySelector; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.api.java.tuple.Tuple3; +import org.apache.flink.api.java.tuple.Tuple4; +import org.apache.flink.ml.api.core.Estimator; +import org.apache.flink.ml.common.datastream.EndOfStreamWindows; +import org.apache.flink.ml.linalg.Vector; +import org.apache.flink.ml.param.Param; +import org.apache.flink.ml.util.ParamUtils; +import org.apache.flink.ml.util.ReadWriteUtils; +import org.apache.flink.streaming.api.datastream.DataStream; +import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment; +import org.apache.flink.streaming.api.functions.windowing.AllWindowFunction; +import org.apache.flink.streaming.api.windowing.windows.TimeWindow; +import org.apache.flink.table.api.Table; +import org.apache.flink.table.api.bridge.java.StreamTableEnvironment; +import org.apache.flink.table.api.internal.TableImpl; +import org.apache.flink.types.Row; +import org.apache.flink.util.Collector; +import org.apache.flink.util.Preconditions; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; + +/** + * An Estimator which implements the naive bayes classification algorithm. + * + * <p>See https://en.wikipedia.org/wiki/Naive_Bayes_classifier. + */ +public class NaiveBayes + implements Estimator<NaiveBayes, NaiveBayesModel>, NaiveBayesParams<NaiveBayes> { + private final Map<Param<?>, Object> paramMap = new HashMap<>(); + + public NaiveBayes() { + ParamUtils.initializeMapWithDefaultValues(paramMap, this); + } + + @Override + public NaiveBayesModel fit(Table... inputs) { + Preconditions.checkArgument(inputs.length == 1); + + final String featuresCol = getFeaturesCol(); + final String labelCol = getLabelCol(); + final double smoothing = getSmoothing(); + + StreamTableEnvironment tEnv = + (StreamTableEnvironment) ((TableImpl) inputs[0]).getTableEnvironment(); + DataStream<Tuple2<Vector, Double>> input = + tEnv.toDataStream(inputs[0]) + .map( + new MapFunction<Row, Tuple2<Vector, Double>>() { + @Override + public Tuple2<Vector, Double> map(Row row) throws Exception { + return new Tuple2<>( + (Vector) row.getField(featuresCol), + (Double) row.getField(labelCol)); + } + }); + + DataStream<NaiveBayesModelData> naiveBayesModel = + input.flatMap(new FlattenFunction()) + .keyBy( + (KeySelector<Tuple4<Double, Integer, Double, Double>, Object>) + value -> new Tuple3<>(value.f0, value.f1, value.f2)) + .window(EndOfStreamWindows.get()) + .reduce( + (ReduceFunction<Tuple4<Double, Integer, Double, Double>>) + (t0, t1) -> { + t0.f3 += t1.f3; + return t0; + }) + .keyBy( + (KeySelector<Tuple4<Double, Integer, Double, Double>, Object>) + value -> new Tuple2<>(value.f0, value.f1)) + .window(EndOfStreamWindows.get()) + .aggregate(new ValueMapFunction()) + .keyBy( + (KeySelector< + Tuple4< + Double, + Integer, + Map<Double, Double>, + Double>, + Object>) + value -> value.f0) + .window(EndOfStreamWindows.get()) + .aggregate(new MapArrayFunction()) + .windowAll(EndOfStreamWindows.get()) + .apply(new GenerateModelFunction(smoothing)); + + NaiveBayesModel model = + new NaiveBayesModel() + .setModelData(NaiveBayesModelData.fromDataStream(tEnv, naiveBayesModel)); + ReadWriteUtils.updateExistingParams(model, paramMap); + return model; + } + + @Override + public void save(String path) throws IOException { + ReadWriteUtils.saveMetadata(this, path); + } + + public static NaiveBayes load(StreamExecutionEnvironment env, String path) throws IOException { + return ReadWriteUtils.loadStageParam(path); + } + + @Override + public Map<Param<?>, Object> getParamMap() { + return paramMap; + } + + /** + * Function to convert each column into tuples of label, feature column index, feature value, + * weight. + */ + private static class FlattenFunction + implements FlatMapFunction< + Tuple2<Vector, Double>, Tuple4<Double, Integer, Double, Double>> { Review comment: Yes, that's right. I'll make the change. I'll make it that users can still choose to input labels that are integer or double, but finally they will be converted to integer. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
