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From unmesha sreeveni <unmeshab...@gmail.com>
Subject PCA in HAdoop MapReduce
Date Wed, 30 Jul 2014 06:27:29 GMT
​I am little bit confused in doing PCA

I am trying it myown and I refered
http://nyx-www.informatik.uni-bremen.de/664/1/smith_tr_02.pdf

1.MR job to calculate mean
2.MR Job to substract mean from the input data(Data Adjust in .pdf)
3.MR job to find covarience and Calculated the eigenvectors and eigenvalues
of the covariance
matrix
4.---
Now need to transform my data
  Step 5: Deriving the new data set in pdf.
It is matrix multiplication ie MR3(step 3) * MR2(Step 2)

Matrix multiplication can be done in using a seperate mapreduce job but i
have MR2 data but I need to transpose MR3 data ie Final data =
RowFeatureVector(MR3) * Row DataAdjust(MR2)

WHile doing transpose in another MR,we will not be sure about the order of
elements they come from mapper

How will we achieve the above transpose.

Please correct me if I am wrong in PCA concepts.​

-- 
*Thanks & Regards *


*Unmesha Sreeveni U.B*
*Hadoop, Bigdata Developer*
*Center for Cyber Security | Amrita Vishwa Vidyapeetham*
http://www.unmeshasreeveni.blogspot.in/

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