/* * Your output should be a in the form of (DoubleWritable score, Text word) * where score is the co-occurrence value for the word. Your output should be * sorted from largest co-occurrence to smallest co-occurrence. */ @Override public void reduce(DoubleWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException { // YOUR CODE HERE int amount = 0; for (Text gram : values) { key.set(new Double(Math.abs(key.get()))); context.write(key, gram); amount++; // When reach N_TO_OUTPUT stop if (amount == N_TO_OUTPUT) break; } }
public void testBinary() throws IOException, InterruptedException { Configuration conf = new Configuration(); Job job = new Job(conf); Path outdir = new Path(System.getProperty("test.build.data", "/tmp"), "outseq"); Random r = new Random(); long seed = r.nextLong(); r.setSeed(seed); FileOutputFormat.setOutputPath(job, outdir); SequenceFileAsBinaryOutputFormat.setSequenceFileOutputKeyClass(job, IntWritable.class); SequenceFileAsBinaryOutputFormat.setSequenceFileOutputValueClass(job, DoubleWritable.class); SequenceFileAsBinaryOutputFormat.setCompressOutput(job, true); SequenceFileAsBinaryOutputFormat.setOutputCompressionType(job, CompressionType.BLOCK); BytesWritable bkey = new BytesWritable(); BytesWritable bval = new BytesWritable(); TaskAttemptContext context = MapReduceTestUtil.createDummyMapTaskAttemptContext(job.getConfiguration()); OutputFormat<BytesWritable, BytesWritable> outputFormat = new SequenceFileAsBinaryOutputFormat(); OutputCommitter committer = outputFormat.getOutputCommitter(context); committer.setupJob(job); RecordWriter<BytesWritable, BytesWritable> writer = outputFormat.getRecordWriter(context); IntWritable iwritable = new IntWritable(); DoubleWritable dwritable = new DoubleWritable(); DataOutputBuffer outbuf = new DataOutputBuffer(); LOG.info("Creating data by SequenceFileAsBinaryOutputFormat"); try { for (int i = 0; i < RECORDS; ++i) { iwritable = new IntWritable(r.nextInt()); iwritable.write(outbuf); bkey.set(outbuf.getData(), 0, outbuf.getLength()); outbuf.reset(); dwritable = new DoubleWritable(r.nextDouble()); dwritable.write(outbuf); bval.set(outbuf.getData(), 0, outbuf.getLength()); outbuf.reset(); writer.write(bkey, bval); } } finally { writer.close(context); } committer.commitTask(context); committer.commitJob(job); InputFormat<IntWritable, DoubleWritable> iformat = new SequenceFileInputFormat<IntWritable, DoubleWritable>(); int count = 0; r.setSeed(seed); SequenceFileInputFormat.setInputPaths(job, outdir); LOG.info("Reading data by SequenceFileInputFormat"); for (InputSplit split : iformat.getSplits(job)) { RecordReader<IntWritable, DoubleWritable> reader = iformat.createRecordReader(split, context); MapContext<IntWritable, DoubleWritable, BytesWritable, BytesWritable> mcontext = new MapContextImpl<IntWritable, DoubleWritable, BytesWritable, BytesWritable>( job.getConfiguration(), context.getTaskAttemptID(), reader, null, null, MapReduceTestUtil.createDummyReporter(), split); reader.initialize(split, mcontext); try { int sourceInt; double sourceDouble; while (reader.nextKeyValue()) { sourceInt = r.nextInt(); sourceDouble = r.nextDouble(); iwritable = reader.getCurrentKey(); dwritable = reader.getCurrentValue(); assertEquals( "Keys don't match: " + "*" + iwritable.get() + ":" + sourceInt + "*", sourceInt, iwritable.get()); assertTrue( "Vals don't match: " + "*" + dwritable.get() + ":" + sourceDouble + "*", Double.compare(dwritable.get(), sourceDouble) == 0); ++count; } } finally { reader.close(); } } assertEquals("Some records not found", RECORDS, count); }