[GitHub] incubator-spark pull request: Principal Component Analysis

[rezazadeh]

Github user rezazadeh commented on the pull request:

    https://github.com/apache/incubator-spark/pull/564#issuecomment-35132663
  
    I made it explicit that the function operates on dense matrices. I will add 
sparse PCA in a different PR since that will be an entirely different algorithm.
    
    @mengxr All changes made.
    @mateiz The input/output of the function is now a DenseMatrix class, 
clearly distinguished from SparseMatrix.