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Re: st: matrix operators that return matrices not allowed in this context
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: matrix operators that return matrices not allowed in this context
Date
Tue, 25 Jan 2011 10:09:00 +0000
It takes a lot of work to try to reconstruct exactly what you are
doing, as this code depends on previous calculations and assignments
and needs a closing brace.
I can't reproduce your main error. Perhaps it is a side-effect of
particular values of your local macros.
Incidentally, the choreography of -mkmat- and -svmat- to add what look
like variables looks unnecessarily complicated. You can just add
variables
Nick
On Tue, Jan 25, 2011 at 12:31 AM, Joe Case Orsini <[email protected]> wrote:
> I'm trying to run a monte carlo simulation, and when i run it with one repetition, everything goes through fine. when i run it for 2 repetitions, stata returns the error message in the subject line.
> the problem is with the matrix b in the code below, defined using the OLS coefficient estimates. also, if i add drop b to the end of the code, stata returns "b not found" even though it will display b during the loop. I'm sure there is an obvious fix here, but would really appreciate an explanation of what's going wrong.
>
>
> forvalues i=1/`reps'{
> gen eps= rnormal(0,exp(`gamma'*x1))
> mkmat eps
> mat y = yfit + eps
> svmat y
> qui reg y x1 x2
> predict e, r
> mat b=_b[_cons]\_b[x1]\_b[x2]
> mat list b
> gen e2=e^2
> qui reg e2 x1 x2
> scalar chi2=`T'*e(r2)
> mat CHISTAT`beta'`gamma'=nullmat(CHISTAT`beta'`gamma')\chi2
>
> drop y eps e e2
> mat drop y eps
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