Java tutorial
/* * 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.mahout.vectorizer; import com.google.common.collect.Lists; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.filecache.DistributedCache; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat; import org.apache.mahout.common.HadoopUtil; import org.apache.mahout.common.Pair; import org.apache.mahout.math.VectorWritable; import org.apache.mahout.vectorizer.common.PartialVectorMerger; import org.apache.mahout.vectorizer.pruner.PrunedPartialVectorMergeReducer; import org.apache.mahout.vectorizer.pruner.WordsPrunerReducer; import java.io.IOException; import java.net.URI; import java.util.List; public final class HighDFWordsPruner { public static final String STD_CALC_DIR = "stdcalc"; public static final String MAX_DF = "max.df"; public static final String MIN_DF = "min.df"; private HighDFWordsPruner() { } public static void pruneVectors(Path tfDir, Path prunedTFDir, Path prunedPartialTFDir, long maxDF, long minDF, Configuration baseConf, Pair<Long[], List<Path>> docFrequenciesFeatures, float normPower, boolean logNormalize, int numReducers) throws IOException, InterruptedException, ClassNotFoundException { int partialVectorIndex = 0; List<Path> partialVectorPaths = Lists.newArrayList(); for (Path path : docFrequenciesFeatures.getSecond()) { Path partialVectorOutputPath = new Path(prunedPartialTFDir, "partial-" + partialVectorIndex++); partialVectorPaths.add(partialVectorOutputPath); pruneVectorsPartial(tfDir, partialVectorOutputPath, path, maxDF, minDF, baseConf); } mergePartialVectors(partialVectorPaths, prunedTFDir, baseConf, normPower, logNormalize, numReducers); HadoopUtil.delete(new Configuration(baseConf), prunedPartialTFDir); } private static void pruneVectorsPartial(Path input, Path output, Path dictionaryFilePath, long maxDF, long minDF, Configuration baseConf) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(baseConf); // this conf parameter needs to be set enable serialisation of conf // values conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization," + "org.apache.hadoop.io.serializer.WritableSerialization"); conf.setLong(MAX_DF, maxDF); conf.setLong(MIN_DF, minDF); DistributedCache.setCacheFiles(new URI[] { dictionaryFilePath.toUri() }, conf); Job job = HadoopUtil.prepareJob(input, output, SequenceFileInputFormat.class, Mapper.class, null, null, WordsPrunerReducer.class, Text.class, VectorWritable.class, SequenceFileOutputFormat.class, conf); job.setJobName( ": Prune Vectors: input-folder: " + input + ", dictionary-file: " + dictionaryFilePath.toString()); HadoopUtil.delete(conf, output); boolean succeeded = job.waitForCompletion(true); if (!succeeded) { throw new IllegalStateException("Job failed!"); } } public static void mergePartialVectors(Iterable<Path> partialVectorPaths, Path output, Configuration baseConf, float normPower, boolean logNormalize, int numReducers) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(baseConf); // this conf parameter needs to be set enable serialisation of conf values conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization," + "org.apache.hadoop.io.serializer.WritableSerialization"); conf.setFloat(PartialVectorMerger.NORMALIZATION_POWER, normPower); conf.setBoolean(PartialVectorMerger.LOG_NORMALIZE, logNormalize); Job job = new Job(conf); job.setJobName("PrunerPartialVectorMerger::MergePartialVectors"); job.setJarByClass(PartialVectorMerger.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(VectorWritable.class); FileInputFormat.setInputPaths(job, getCommaSeparatedPaths(partialVectorPaths)); FileOutputFormat.setOutputPath(job, output); job.setMapperClass(Mapper.class); job.setInputFormatClass(SequenceFileInputFormat.class); job.setReducerClass(PrunedPartialVectorMergeReducer.class); job.setOutputFormatClass(SequenceFileOutputFormat.class); job.setNumReduceTasks(numReducers); HadoopUtil.delete(conf, output); boolean succeeded = job.waitForCompletion(true); if (!succeeded) { throw new IllegalStateException("Job failed!"); } } private static String getCommaSeparatedPaths(Iterable<Path> paths) { StringBuilder commaSeparatedPaths = new StringBuilder(100); String sep = ""; for (Path path : paths) { commaSeparatedPaths.append(sep).append(path.toString()); sep = ","; } return commaSeparatedPaths.toString(); } }