Hi  Srini,
   If you want to get value like the following example using scala, some other 
language also like this 
     " mat.rows.collect().apply(i)
      val cov = mat.computeCovariance()
      cov.apply(i, j)
     "
   mat is RowMatrix type and  the cov is Matrix type.
  

 

 ------------------ ???????? ------------------
  ??????: "Srivathsan Srinivas";<srivathsan.srini...@gmail.com>;
 ????????: 2016??1??22??(??????) ????1:12
 ??????: "zhangjp"<592426...@qq.com>; 
 ????: "user"<user@spark.apache.org>; 
 ????: Re: retrieve cell value from a rowMatrix.

 

 Hi Zhang,    I am new to Scala and Spark. I am not a Java guy (more of Python 
and R guy). Just began playing with matrices in MlLib and looks painful to do 
simple things. If you can show me a small example, it would help. Apply 
function is not available in RowMatrix. 
 

 For eg.,
 

 import org.apache.spark.mllib.linalg.distributed.RowMatrix
 

 /* retrive a cell value */
 def getValue(m: RowMatrix): Double = {
    <what should go in here>???
 }
 

 

 Likewise, I have trouble adding two RowMatrices
 

 /* add two RowMatrices */
 def addRowMatrices(a: RowMatrix, b: RowMatrix): RowMatrix = {
 

 }
 

 

 From what I have read on Stackoverflow and other places is that such simple 
things are not exposed in MlLib. But, they are heavily used in the underlying 
Breeze libraries. Hence, one should convert the rowMatrics to its Breeze 
equivalent, do the required operations and convert it back to rowMatrix. I am 
still learning how to do this kind of conversion back and forth. If you have 
small examples, it would be very helpful.
 

 

 Thanks!
 Srini.

 
 On Wed, Jan 20, 2016 at 10:08 PM, zhangjp <592426...@qq.com> wrote:
   
  use apply(i,j) function.
 can u know how  to save matrix to a file using java language?

 

 ------------------ ???????? ------------------
  ??????: "Srivathsan Srinivas";<srivathsan.srini...@gmail.com>;
 ????????: 2016??1??21??(??????) ????9:04
 ??????: "user"<user@spark.apache.org>; 
 
 ????: retrieve cell value from a rowMatrix.

   

 Hi,     Is there a way to retrieve the cell value of a rowMatrix? Like m(i,j)? 
The docs say that the indices are long. Maybe I am doing something wrong...but, 
there doesn't seem to be any such direct method.
 

 Any suggestions?
 

-- 
 Thanks,
Srini. 


 






 

-- 
 Thanks,
Srini.

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