org.apache.mahout.math.hadoop
Class MatrixColumnMeansJob.MatrixColumnMeansMapper
java.lang.Object
org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.Writable,VectorWritable,org.apache.hadoop.io.NullWritable,VectorWritable>
org.apache.mahout.math.hadoop.MatrixColumnMeansJob.MatrixColumnMeansMapper
- Enclosing class:
- MatrixColumnMeansJob
public static class MatrixColumnMeansJob.MatrixColumnMeansMapper
- extends org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.Writable,VectorWritable,org.apache.hadoop.io.NullWritable,VectorWritable>
Mapper for calculation of column-wise mean.
Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Mapper |
org.apache.hadoop.mapreduce.Mapper.Context |
Method Summary |
void |
cleanup(org.apache.hadoop.mapreduce.Mapper.Context context)
The column-wise sum is written at the cleanup stage. |
void |
map(org.apache.hadoop.io.Writable r,
VectorWritable v,
org.apache.hadoop.mapreduce.Mapper.Context context)
The mapper computes a running sum of the vectors the task has seen. |
void |
setup(org.apache.hadoop.mapreduce.Mapper.Context context)
|
Methods inherited from class org.apache.hadoop.mapreduce.Mapper |
run |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
MatrixColumnMeansJob.MatrixColumnMeansMapper
public MatrixColumnMeansJob.MatrixColumnMeansMapper()
setup
public void setup(org.apache.hadoop.mapreduce.Mapper.Context context)
- Overrides:
setup
in class org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.Writable,VectorWritable,org.apache.hadoop.io.NullWritable,VectorWritable>
map
public void map(org.apache.hadoop.io.Writable r,
VectorWritable v,
org.apache.hadoop.mapreduce.Mapper.Context context)
throws IOException
- The mapper computes a running sum of the vectors the task has seen.
Element 0 of the running sum vector contains a count of the number of
vectors that have been seen. The remaining elements contain the
column-wise running sum. Nothing is written at this stage
- Overrides:
map
in class org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.Writable,VectorWritable,org.apache.hadoop.io.NullWritable,VectorWritable>
- Throws:
IOException
cleanup
public void cleanup(org.apache.hadoop.mapreduce.Mapper.Context context)
throws InterruptedException,
IOException
- The column-wise sum is written at the cleanup stage. A single reducer is
forced so null can be used for the key
- Overrides:
cleanup
in class org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.Writable,VectorWritable,org.apache.hadoop.io.NullWritable,VectorWritable>
- Throws:
InterruptedException
IOException
Copyright © 2008–2014 The Apache Software Foundation. All rights reserved.