/**
* 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.df.mapreduce.inmem;
import java.io.IOException;
import java.util.Random;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.mahout.common.RandomUtils;
import org.apache.mahout.df.Bagging;
import org.apache.mahout.df.callback.SingleTreePredictions;
import org.apache.mahout.df.data.Data;
import org.apache.mahout.df.data.DataLoader;
import org.apache.mahout.df.data.Dataset;
import org.apache.mahout.df.mapreduce.Builder;
import org.apache.mahout.df.mapreduce.MapredMapper;
import org.apache.mahout.df.mapreduce.MapredOutput;
import org.apache.mahout.df.mapreduce.inmem.InMemInputFormat.InMemInputSplit;
import org.apache.mahout.df.node.Node;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* In-memory mapper that grows the trees using a full copy of the data loaded
* in-memory. The number of trees to grow is determined by the current
* InMemInputSplit.
*/
public class InMemMapper extends
MapredMapper<IntWritable, NullWritable, IntWritable, MapredOutput> {
private static final Logger log = LoggerFactory.getLogger(InMemMapper.class);
private Bagging bagging;
private Random rng;
private Data data;
/**
* Load the training data
*
* @param conf
* @return
* @throws RuntimeException if the data could not be loaded
*/
private static Data loadData(Configuration conf, Dataset dataset) throws IOException {
Path dataPath = Builder.getDistributedCacheFile(conf, 1);
FileSystem fs = FileSystem.get(dataPath.toUri(), conf);
return DataLoader.loadData(dataset, fs, dataPath);
}
@Override
protected void setup(Context context) throws IOException,
InterruptedException {
super.setup(context);
Configuration conf = context.getConfiguration();
log.info("Loading the data...");
data = loadData(conf, getDataset());
log.info("Data loaded : " + data.size() + " instances");
bagging = new Bagging(getTreeBuilder(), data);
}
@Override
protected void map(IntWritable key, NullWritable value, Context context)
throws IOException, InterruptedException {
map(key, context);
}
public void map(IntWritable key, Context context) throws IOException, InterruptedException {
SingleTreePredictions callback = null;
int[] predictions = null;
if (isOobEstimate() && !isNoOutput()) {
callback = new SingleTreePredictions(data.size());
predictions = callback.getPredictions();
}
initRandom((InMemInputSplit)context.getInputSplit());
log.debug("Building...");
Node tree = bagging.build(key.get(), rng, callback);
if (!isNoOutput()) {
log.debug("Outputing...");
MapredOutput mrOut = new MapredOutput(tree, predictions);
context.write(key, mrOut);
}
}
protected void initRandom(InMemInputSplit split) {
if (rng == null) { // first execution of this mapper
Long seed = split.getSeed();
log.debug("Initialising rng with seed : " + seed);
if (seed == null)
rng = RandomUtils.getRandom();
else
rng = RandomUtils.getRandom(seed);
}
}
}