org.apache.hadoop.examples

Class QuasiMonteCarlo.QmcReducer

java.lang.Object

org.apache.hadoop.mapreduce.Reducer<org.apache.hadoop.io.BooleanWritable,org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.WritableComparable<?>,org.apache.hadoop.io.Writable>

org.apache.hadoop.examples.QuasiMonteCarlo.QmcReducer

Enclosing class:

QuasiMonteCarlo

public static class QuasiMonteCarlo.QmcReducer
extends org.apache.hadoop.mapreduce.Reducer<org.apache.hadoop.io.BooleanWritable,org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.WritableComparable<?>,org.apache.hadoop.io.Writable>

Reducer class for Pi estimation. Accumulate points inside/outside results from the mappers.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Reducer

org.apache.hadoop.mapreduce.Reducer.Context

Constructor Summary

Constructors

Constructor and Description
QmcReducer()

Method Summary

Modifier and Type	Method and Description
void	cleanup(org.apache.hadoop.mapreduce.Reducer.Context context) Reduce task done, write output to a file.
void	reduce(org.apache.hadoop.io.BooleanWritable isInside, Iterable<org.apache.hadoop.io.LongWritable> values, org.apache.hadoop.mapreduce.Reducer.Context context) Accumulate number of points inside/outside results from the mappers.

Methods inherited from class org.apache.hadoop.mapreduce.Reducer

run, setup

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

QmcReducer

public QmcReducer()

Method Detail

reduce

public void reduce(org.apache.hadoop.io.BooleanWritable isInside,
                   Iterable<org.apache.hadoop.io.LongWritable> values,
                   org.apache.hadoop.mapreduce.Reducer.Context context)
            throws IOException,
                   InterruptedException

Accumulate number of points inside/outside results from the mappers.

Overrides:

reduce in class org.apache.hadoop.mapreduce.Reducer<org.apache.hadoop.io.BooleanWritable,org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.WritableComparable<?>,org.apache.hadoop.io.Writable>

Parameters:

isInside - Is the points inside?

values - An iterator to a list of point counts

context - dummy, not used here.

Throws:

IOException

InterruptedException

cleanup

public void cleanup(org.apache.hadoop.mapreduce.Reducer.Context context)
             throws IOException

Reduce task done, write output to a file.

Overrides:

cleanup in class org.apache.hadoop.mapreduce.Reducer<org.apache.hadoop.io.BooleanWritable,org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.WritableComparable<?>,org.apache.hadoop.io.Writable>

Throws:

IOException