package org.apache.mahout.vectorizer;
/**
* 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.
*/
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.ArrayList;
import java.util.List;
public class HighDFWordsPruner {
public static final String OUT_DIR_SUFFIX = "-pruned";
public static final String STD_CALC_DIR = "stdcalc";
public static final String MAX_DF = "max.df";
private HighDFWordsPruner() {
}
public static void pruneVectors(Path tfDir, Path prunedTFDir, Path prunedPartialTFDir, long maxDF,
Configuration baseConf,
Pair<Long[], List<Path>> docFrequenciesFeatures,
float normPower,
boolean logNormalize,
int numReducers) throws IOException, InterruptedException,
ClassNotFoundException {
int partialVectorIndex = 0;
List<Path> partialVectorPaths = new ArrayList<Path>();
for (Path path : docFrequenciesFeatures.getSecond()) {
Path partialVectorOutputPath = new Path(prunedPartialTFDir, "partial-" + partialVectorIndex++);
partialVectorPaths.add(partialVectorOutputPath);
pruneVectorsPartial(tfDir, partialVectorOutputPath, path, maxDF, 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,
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);
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);
job.waitForCompletion(true);
}
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);
job.waitForCompletion(true);
}
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();
}
}