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https://issues.apache.org/jira/browse/MAPREDUCE-2811?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Allen Wittenauer updated MAPREDUCE-2811:
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    Description: Like HADOOP-372, we have a multi format Reducer too. Someone 
suggested that if we need different reducers and map implementations(like what 
i need) I was better of by writing 2 jobs. I dont quite agree. I am calculating 
2 big matrices that must be calculated in the map step, summed in the reducers 
multiplied and then written to a file. The First mapper sums a matrix  based on 
the i,j th index(key) into the file and the second mapper adds the N*1  
dimension vector that uses a new line as key. These keys must be passed as such 
to the reduce process.  (was: Like the Patch released here 
https://issues.apache.org/jira/browse/HADOOP-372 can we have a multi format 
Reducer too. Someone suggested that if we need different reducers and map 
implementations(like what i need) I was better of by writing 2 jobs. I dont 
quite agree. I am calculating 2 big matrices that must be calculated in the map 
step, summed in the reducers multiplied and then written to a file. The First 
mapper sums a matrix  based on the i,j th index(key) into the file and the 
second mapper adds the N*1  dimension vector that uses a new line as key. These 
keys must be passed as such to the reduce process.)

> Adding Multiple Reducers implementations.
> -----------------------------------------
>
>                 Key: MAPREDUCE-2811
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2811
>             Project: Hadoop Map/Reduce
>          Issue Type: New Feature
>            Reporter: Sidharth Gupta
>
> Like HADOOP-372, we have a multi format Reducer too. Someone suggested that 
> if we need different reducers and map implementations(like what i need) I was 
> better of by writing 2 jobs. I dont quite agree. I am calculating 2 big 
> matrices that must be calculated in the map step, summed in the reducers 
> multiplied and then written to a file. The First mapper sums a matrix  based 
> on the i,j th index(key) into the file and the second mapper adds the N*1  
> dimension vector that uses a new line as key. These keys must be passed as 
> such to the reduce process.



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