st: RE: what is wrong with my nl function in stata?

[Kieran McCaul <kieran.mccaul@uwa.edu.au>]

...

There is a "*" missing in the second exp() term:

gen double `eterm'=`income'*exp(`k2'*`prov1')+`income'*exp(`k2'`prov2')+`income'*exp(`k2'*`prov3')  `if'

It should be:

gen double `eterm'=`income'*exp(`k2'*`prov1')+`income'*exp(`k2'*`prov2')+`income'*exp(`k2'*`prov3')  `if'



-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of ???
Sent: Thursday, 30 January 2014 12:56 AM
To: statalist@hsphsun2.harvard.edu
Subject: st: what is wrong with my nl function in stata?

Dear all
I try to estimate a nonlinear lease square function in stata,It need to estimate a compound summation terms like
lnwage_ij=ko+k1*ln(?(income*exp(k2*d_ij) , d_ijis the distance between individual observation i and observation j. My problems is how to deal with the ? in my nl evaluation function. My naive code are as follows,

 the code is as follows:
program nlwage1
version 12
syntax varlist(min=5 max=5) if, at(name) local lnwage : word 1 of `varlist'
local income : word 2 of `varlist'
local prov1: word 3 of `varlist'
local prov2: word 4 of `varlist'
local prov3:word 5 of `varlist'

tempname k0 k1 k2
scalar `k0' = `at'[1, 1]
scalar `k1' = `at'[1, 2]
scalar `k2' = `at'[1, 3]

tempvar eterm

gen double `eterm'=`income'*exp(`k2'*`prov1')+`income'*exp(`k2'`prov2')+`income'*exp(`k2'*`prov3')
 `if'

replace `lnwage' = `k0' +`k1'*log(`eterm')  `if'

end

nl wage1 @lnwage income prov1 prov2 prov3, parameters(k0 k1 k2)
initial(k0 0.05 k1 0.02 k2 0.03)


it return error

nlwage1 returned 199
verify that nlwage1 is a function evaluator program

What is wrong with my stata code?
I sincerely hope that someone can help me

Zhiqiangzhang

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