Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.

st: Matrices utilities, Basic calculations. When to start using Mata over Stata?‏

 From Radaf paf To Subject st: Matrices utilities, Basic calculations. When to start using Mata over Stata?‏ Date Fri, 23 Apr 2010 11:50:20 +0000

```Hi all,

I have a total of 20 matrices, A1-A10 and B1-B10 of size
25x36

I am trying to do the sum of each row of the matrix A and
compare them with the sum of each row of the matrix B. Then I retain the
highest sum and put it in a new matrix, say C.

The "rowsum" utility in Mata is appealing, but I couldn't figure out how to create
the loops ( no "foreach" command?), generate new matrixes names
automatically (for the matrices C) and access my 20 matrices within the
loops in Mata.

Here is what I would do if I could use "rowsum"
in Stata:

foreach n in 1 2 3 4 5 6 7 8 9 10 {;

matrix c'n´= J(rowsof(A'n´),1,0)     *I create my matrix c (vector of
25 rows) containing only 0 values ;

foreach i in 1-25 {;
* where i correspond to the number of rows;

R_sum_A'n´=rowsum(A'n´) ;
R_sum_B'n´=rowsum(B'n´) ;

*I compare the two sums and if the rowsum of A is bigger than B I
put it in the new matric C, if not I leave it equals to 0 ;

if el(R_sum_A'n´,'i´,1)> el(R_sum_B'n´,'i´,1)

matrix C'n´['i´,1] =el(R_sum_A'n´,'i´,1) ;

};
};

But I cannot use "rowsum" into stata . So what would you suggest ?

Thanks a lot

Raphael
_________________________________________________________________
Your E-mail and More On-the-Go. Get Windows Live Hotmail Free.
https://signup.live.com/signup.aspx?id=60969
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```