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Re: st: constant in nonlinear squares


From   "Brian P. Poi" <[email protected]>
To   [email protected]
Subject   Re: st: constant in nonlinear squares
Date   Tue, 3 Apr 2007 15:17:03 -0500 (CDT)

On Tue, 3 Apr 2007, Maritza Sotomayor wrote:

Dear statalist members:
I'm trying to include a constant in a nonlinear function. I used the
substitutable expression with Model 2 option -hasconstant- which
needs a parameter. I generated a constant variable (column of ones,
called constante) but I get an error r(498) "constante not found
among parameters".
-nl (iitt = 1/(1+exp(-1*{xb: constante lavrgdp ldpcgdp ltc
lroyalsale latarif lagi lavgest ldcap}))),  nolog
hasconstant(constante)-
constante not found among parameters
check hasconstant() option or try using nl without it
r(498);

Maritza,

The hasconstant() option expects the name of a parameter, not the name of a variable. Since you are using the notation {eqname:varlist} to specify a linear combination, in your case the parameter on the variable named constante will be xb_constante. Thus, you would type

. nl ... , hasconstant(xb_constante)

Hope this helps

-- Brian Poi
-- [email protected]

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