vacaly commented on code in PR #192: URL: https://github.com/apache/flink-ml/pull/192#discussion_r1099929243
########## flink-ml-lib/src/main/java/org/apache/flink/ml/recommendation/swing/Swing.java: ########## @@ -0,0 +1,452 @@ +/* + * 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.recommendation.swing; + +import org.apache.flink.api.common.state.ListState; +import org.apache.flink.api.common.state.ListStateDescriptor; +import org.apache.flink.api.common.typeinfo.BasicTypeInfo; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.common.typeinfo.Types; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.api.java.tuple.Tuple3; +import org.apache.flink.api.java.typeutils.RowTypeInfo; +import org.apache.flink.iteration.operator.OperatorStateUtils; +import org.apache.flink.ml.api.AlgoOperator; +import org.apache.flink.ml.common.datastream.TableUtils; +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.runtime.state.StateInitializationContext; +import org.apache.flink.runtime.state.StateSnapshotContext; +import org.apache.flink.streaming.api.datastream.DataStream; +import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator; +import org.apache.flink.streaming.api.operators.AbstractStreamOperator; +import org.apache.flink.streaming.api.operators.BoundedOneInput; +import org.apache.flink.streaming.api.operators.OneInputStreamOperator; +import org.apache.flink.streaming.runtime.streamrecord.StreamRecord; +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.table.catalog.ResolvedSchema; +import org.apache.flink.types.Row; +import org.apache.flink.util.Preconditions; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.LinkedHashSet; +import java.util.List; +import java.util.Map; +import java.util.Map.Entry; +import java.util.Random; +import java.util.Set; + +/** + * An AlgoOperator which implements the Swing algorithm. + * + * <p>Swing is an item recall model. The topology of user-item graph usually can be described as + * user-item-user or item-user-item, which are like 'swing'. For example, if both user <em>u</em> + * and user <em>v</em> have purchased the same commodity <em>i</em> , they will form a relationship + * diagram similar to a swing. If <em>u</em> and <em>v</em> have purchased commodity <em>j</em> in + * addition to <em>i</em>, it is supposed <em>i</em> and <em>j</em> are similar. The formula of + * Swing is + * + * <p>$$ w_{(i,j)}=\sum_{u\in U_i\cap U_j}\sum_{v\in U_i\cap + * U_j}{\frac{1}{{(I_u+\alpha_1)}^\beta}}*{\frac{1}{{(I_v+\alpha_1)}^\beta}}*{\frac{1}{\alpha\_2+|I_u\cap + * I_v|}} $$ + * + * <p>This implementation is based on the algorithm proposed in the paper: "Large Scale Product + * Graph Construction for Recommendation in E-commerce" by Xiaoyong Yang, Yadong Zhu and Yi Zhang. + * (https://arxiv.org/pdf/2010.05525.pdf) + */ +public class Swing implements AlgoOperator<Swing>, SwingParams<Swing> { + private final Map<Param<?>, Object> paramMap = new HashMap<>(); + + public Swing() { + ParamUtils.initializeMapWithDefaultValues(paramMap, this); + } + + @Override + public Table[] transform(Table... inputs) { + + final String userCol = getUserCol(); + final String itemCol = getItemCol(); + Preconditions.checkArgument(inputs.length == 1); + final ResolvedSchema schema = inputs[0].getResolvedSchema(); + + if (!(Types.LONG.equals(TableUtils.getTypeInfoByName(schema, userCol)) + && Types.LONG.equals(TableUtils.getTypeInfoByName(schema, itemCol)))) { + throw new IllegalArgumentException("The types of user and item columns must be Long."); + } + + StreamTableEnvironment tEnv = + (StreamTableEnvironment) ((TableImpl) inputs[0]).getTableEnvironment(); + + SingleOutputStreamOperator<Tuple2<Long, Long>> itemUsers = + tEnv.toDataStream(inputs[0]) + .map( + row -> { + if (row.getFieldAs(userCol) == null + || row.getFieldAs(itemCol) == null) { + throw new RuntimeException( + "Data of user and item column must not be null"); + } + return Tuple2.of( + ((Number) row.getFieldAs(userCol)).longValue(), + ((Number) row.getFieldAs(itemCol)).longValue()); Review Comment: Yep -- This is an automated message from the Apache Git Service. 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