st: RE: How do I suppress output in mata?

["Martin Weiss" <martin.weiss1@gmx.de>]

<>

Have you had a look at -displayas()- ([M-5])? 

Assuming you are a Stata 11 user, you can also search the pdf manual for
-mata- for the word "suppress". It does appear a couple of times...


HTH
Martin

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Kramer
Sent: Sonntag, 15. November 2009 10:11
To: statalist@hsphsun2.harvard.edu
Subject: st: How do I suppress output in mata?

Hello - 

I'm working in Stata version 10 on a Mac.

I've just written my first function in mata and I need some help.  My
function takes a column vector of length r, and creates a r x r matrix with
elements that equal 1 if two elements of the column vector are the same, and
zero otherwise.  The function works well, except for the fact that it
returns the r x r matrix to the screen.  Since the vectors that I need to
input are 5000-6000 rows long, this is a problem.  I've tried typing
"quietly" before I execute the function in mata, and that returns the error:


invalid expression
r(3000);

I've tried adding the word "quietly" before the return line in my function,
i.e.:

quietly return(WDY0)

but then I got this error message:

'return' found where almost anything else expected

I've looked through the "programing" and "mata" documentation, along with 
Stata help and the statalist archives (and Google) and can't figure out a
solution to this problem.  If anyone has an answer, it would be much
appreciated.  I've included the text of my program below.

Thank you for your consideration,

Kramer

*this is a do-file to create the function "district"
*   "district" takes the district number observation from each school and 
*   creates a matrix whose elements are one if school i != school j AND if
*   school i and school j are in the same district

*INPUTS: T = column vector of district numbers from a given year

* OUTPUT: WDY0 = matrix whose elements are one if school i != school j AND
if
*                school i and school j are in the same district

mata:

real matrix district(real colvector T)
{
        real scalar r
        real matrix A
        real matrix B
        real scalar i
        real matrix WDY0

        r = rows(T)
        
        A = J(r,r,0)
        for(i=1; i<=r; i++){
            A[i,.]=T'
            }

        B = J(r,r,0)
        for(i=1; i<=r; i++){
            B[.,i]=T
            }        
            
        WDY0 = A - B
        
        for(i=1; i<=r; i++){
            for(j=1; j<=r; j++){
                if((WDY0[i,j]==0) & (i!=j))
                    WDY0[i,j] = 1
                else WDY0[i,j]=0
                }
            }
            
        return(WDY0)
}

mata mosave district(), dir(/Users/Kramer/Desktop/Thesis/) replace

end



      

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