/**
* 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.classifier.bayes.mapreduce.bayes;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.KeyValueTextInputFormat;
import org.apache.hadoop.mapred.SequenceFileOutputFormat;
import org.apache.mahout.classifier.ConfusionMatrix;
import org.apache.mahout.classifier.bayes.common.BayesParameters;
import org.apache.mahout.common.StringTuple;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
/** Create and run the Bayes Classifier */
public class BayesClassifierDriver {
private static final Logger log = LoggerFactory.getLogger(BayesClassifierDriver.class);
private BayesClassifierDriver() {
}
/**
* Run the job
*
* @param params The Job parameters containing the gramSize, input output folders, defaultCat, encoding
*/
public static final void runJob(BayesParameters params) throws IOException {
JobClient client = new JobClient();
JobConf conf = new JobConf(BayesClassifierDriver.class);
conf.setJobName("Bayes Classifier Driver running over input: " + params.get("testDirPath"));
conf.setOutputKeyClass(StringTuple.class);
conf.setOutputValueClass(DoubleWritable.class);
FileInputFormat.setInputPaths(conf, new Path(params.get("testDirPath")));
Path outPath = new Path(params.get("testDirPath") + "-output");
FileOutputFormat.setOutputPath(conf, outPath);
conf.setInputFormat(KeyValueTextInputFormat.class);
conf.setMapperClass(BayesClassifierMapper.class);
conf.setCombinerClass(BayesClassifierReducer.class);
conf.setReducerClass(BayesClassifierReducer.class);
conf.setOutputFormat(SequenceFileOutputFormat.class);
conf.set("io.serializations",
"org.apache.hadoop.io.serializer.JavaSerialization,org.apache.hadoop.io.serializer.WritableSerialization");
FileSystem dfs = FileSystem.get(outPath.toUri(), conf);
if (dfs.exists(outPath)) {
dfs.delete(outPath, true);
}
conf.set("bayes.parameters", params.toString());
client.setConf(conf);
JobClient.runJob(conf);
Path outputFiles = new Path(outPath.toString() + "/part*");
ConfusionMatrix matrix = readResult(dfs, outputFiles, conf, params);
log.info("{}",matrix.summarize());
}
private static ConfusionMatrix readResult(FileSystem fs, Path pathPattern, Configuration conf, BayesParameters params)
throws IOException {
StringTuple key = new StringTuple();
DoubleWritable value = new DoubleWritable();
String defaultLabel = params.get("defaultCat");
FileStatus[] outputFiles = fs.globStatus(pathPattern);
Map<String, Map<String, Integer>> confusionMatrix = new HashMap<String, Map<String, Integer>>();
for (FileStatus fileStatus : outputFiles) {
Path path = fileStatus.getPath();
SequenceFile.Reader reader = new SequenceFile.Reader(fs, path, conf);
while (reader.next(key, value)) {
String correctLabel = key.stringAt(1);
String classifiedLabel = key.stringAt(2);
Map<String, Integer> rowMatrix = confusionMatrix.get(correctLabel);
if(rowMatrix == null)
rowMatrix = new HashMap<String, Integer>();
Integer count = Double.valueOf(value.get()).intValue();
rowMatrix.put(classifiedLabel, count);
confusionMatrix.put(correctLabel, rowMatrix);
}
}
ConfusionMatrix matrix = new ConfusionMatrix(confusionMatrix.keySet(), defaultLabel);
for(Map.Entry<String, Map<String, Integer>> correctLabelSet:confusionMatrix.entrySet())
{
Map<String, Integer> rowMatrix = correctLabelSet.getValue();
for(Map.Entry<String, Integer> classifiedLabelSet : rowMatrix.entrySet())
{
matrix.addInstance(correctLabelSet.getKey(), classifiedLabelSet.getKey());
matrix.putCount(correctLabelSet.getKey(), classifiedLabelSet.getKey(), classifiedLabelSet.getValue());
}
}
return matrix;
}
}