Solodye commented on a change in pull request #193: [WIP][HIVEMALL-253-2] map_roulette UDF URL: https://github.com/apache/incubator-hivemall/pull/193#discussion_r297040383
########## File path: core/src/main/java/hivemall/tools/map/MapRouletteUDF.java ########## @@ -0,0 +1,209 @@ +/* + * 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 hivemall.tools.map; + +import static hivemall.utils.lang.StringUtils.join; + +import hivemall.utils.hadoop.HiveUtils; + +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Random; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; + +import org.apache.hadoop.hive.ql.exec.Description; +import org.apache.hadoop.hive.ql.exec.UDFArgumentException; +import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException; +import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException; +import org.apache.hadoop.hive.ql.metadata.HiveException; +import org.apache.hadoop.hive.ql.udf.UDFType; +import org.apache.hadoop.hive.ql.udf.generic.GenericUDF; +import org.apache.hadoop.hive.serde2.objectinspector.MapObjectInspector; +import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector; +import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils; +import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector; +import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils; + +import com.clearspring.analytics.util.Preconditions; + +/** + * The map_roulette returns a map key based on weighted random sampling of map values. + */ +@Description(name = "map_roulette", + value = "_FUNC_(Map<K, number> map [, (const) int/bigint seed])" + + " - Returns a map key based on weighted random sampling of map values." + + " Average of values is used for null values") +@UDFType(deterministic = false, stateful = false) // it is false because it return value base on probability +public final class MapRouletteUDF extends GenericUDF { + + private transient MapObjectInspector mapOI; + private transient PrimitiveObjectInspector valueOI; + @Nullable + private transient PrimitiveObjectInspector seedOI; + + @Nullable + private transient Random _rand; + + @Override + public ObjectInspector initialize(ObjectInspector[] argOIs) throws UDFArgumentException { + if (argOIs.length != 1 && argOIs.length != 2) { + throw new UDFArgumentLengthException( + "Expected exactly one argument for map_roulette: " + argOIs.length); + } + if (argOIs[0].getCategory() != ObjectInspector.Category.MAP) { + throw new UDFArgumentTypeException(0, + "Only map type argument is accepted but got " + argOIs[0].getTypeName()); + } + + this.mapOI = HiveUtils.asMapOI(argOIs[0]); + this.valueOI = HiveUtils.asNumberOI(mapOI.getMapValueObjectInspector()); + + if (argOIs.length == 2) { + ObjectInspector argOI1 = argOIs[1]; + if (HiveUtils.isIntegerOI(argOI1) == false) { + throw new UDFArgumentException( + "The second argument of map_roulette must be integer type: " + + argOI1.getTypeName()); + } + if (ObjectInspectorUtils.isConstantObjectInspector(argOI1)) { + long seed = HiveUtils.getAsConstLong(argOI1); + this._rand = new Random(seed); // fixed seed + } else { + this.seedOI = HiveUtils.asLongCompatibleOI(argOI1); + } + } else { + this._rand = new Random(); // random seed + } + + return mapOI.getMapKeyObjectInspector(); + } + + @Override + public Object evaluate(DeferredObject[] arguments) throws HiveException { + Random rand = _rand; + if (rand == null) { + Object arg1 = arguments[1].get(); + if (arg1 == null) { + rand = new Random(); + } else { + long seed = HiveUtils.getLong(arg1, seedOI); + rand = new Random(seed); + } + } + + Map<Object, Double> input = getObjectDoubleMap(arguments[0], mapOI, valueOI); + if (input == null) { + return null; + } + + return rouletteWheelSelection(input, rand); + } + + @Nullable + private static Map<Object, Double> getObjectDoubleMap(@Nonnull final DeferredObject argument, + @Nonnull final MapObjectInspector mapOI, + @Nonnull final PrimitiveObjectInspector valueOI) throws HiveException { + final Map<?, ?> m = mapOI.getMap(argument.get()); + if (m == null) { + return null; + } + final int size = m.size(); + if (size == 0) { + return null; + } + + final Map<Object, Double> result = new HashMap<>(size); + double sum = 0.d; + int cnt = 0; + for (Map.Entry<?, ?> entry : m.entrySet()) { + Object value = entry.getValue(); + if (value == null) { + continue; + } + final double v = PrimitiveObjectInspectorUtils.convertPrimitiveToDouble(value, valueOI); + if (v < 0) { + throw new UDFArgumentException( + "Map value must be greather than or equals to zero: " + entry.getValue()); + } + + Object key = entry.getKey(); + result.put(key, Double.valueOf(v)); + + sum += v; + cnt++; + } + + if (result.size() < m.size()) { + // fillna with the avg value + final Double avg = Double.valueOf(sum / cnt); Review comment: Yes，`avg /= m.size();` was revised, so Jerry in testcase ' testRoulette()' should be elected for the 3rd place ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
