You can't include full matrices on the LHS of
a -replace- command. The syntax of -replace- is
replace oldvar =exp [if] [in] [, nopromote]
and so what occurs on the LHS can _only_ be
an existing variable name.
The situation for the RHS is not quite so
clear-cut, but the whole of the RHS could not
be, or evaluate to, a full matrix, if only for the reason above.
In Stata 9, Mata or the matrix programming language
might be enough for your problem.
Nick
[email protected]
Randall K. Q. Akee, Ph.D.
> I have a program that I want to use with the NL (non-linear least
> squares) command in Stata. I just have a simple question
> with regard to
> Stata v.9, for my objective function that gets "replaced" in the NL
> program, is it possible to have the Left Hand side and the ride hand
> side both be matrices? Typically, I have seen examples (in the stata
> manual and other people's do files), where the right hand
> side is simply
> a single equation.
>
> For instance:
>
> capture program drop nltest
> program define nltest
> version 9.0
> if "`1'"== { global S_1 b1 b2 b3
> }
> replace `1'=$b1*X+exp($b2*$b3)
> end
>
> nl test data1 X etc. . .
>
> I want to know if Stata v.9 can handle a matrix on both the right hand
> side and left hand side (can data1 and X be matrices?) in the
> line above
> that begins with "replace". I have several equations that I
> would like
> to fit with the same parameters.
>
> I know Stata v.10 has the NLSUR command, I just want to know
> if I should
> wait for this version.
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