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st: RE: nonlinear least square


From   "Scott Merryman" <smerryman@kc.rr.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: nonlinear least square
Date   Mon, 22 Aug 2005 10:46:13 -0500

There are a few problems:

1. To call program, it should be -nlsal spe hpe- not -nl sal: spe hpe-

2. The -if- option should be in brackets.

3. You are not actually calling -nl-  Do you mean something like this:


program  nlsal, rclass
	syntax varlist(min = 2 max =2) [if]
	tokenize `varlist' `if'
	reg `1' `2'
	local a = _b[_cons]
	local b = _b[`2']
	nl (`1'= {alpha=`a'} + {beta=`b'}*`2'^{gamma=1} ) `if', nolog
	return local title "`1' = alpha+beta*`2'^gamma"
end


Scott

> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-
> statalist@hsphsun2.harvard.edu] On Behalf Of clothilde dufort
> Sent: Monday, August 22, 2005 10:05 AM
> To: statalist@hsphsun2.harvard.edu
> Subject: st: nonlinear least square
> 
> hi,
> 
> I am trying to estimate the follwing non linear
> equation :
> 
> spe=alpha + beta*hpe^gamma
> 
> so I use the function "nl" in stata and before I write
> the following program.
> 
> ---
> 
> program nlsal, rclass
> 
> syntax varlist(min=2 max=2) [aw fw iw] if
> 
> local lhs: word 1 of `varlist'
> 
> local rhs: word 2 of `varlist'
> 
> regress `lhs' `rhs' [`weight'`exp'] `if'
> 
> tempname a b
> 
> scalar `a' = _b[_cons]
> 
> scalar `b' = _b[`rhs']
> 
> return local eq "`lhs' =
> {alpha=`=`a''}+{beta=`=`b''}*`rhs'^{gamma=1}"
> 
> return local title "`lhs' = alpha+beta*`rhs'^gamma"
> 
> end
> 
> ---
> 
> and then i write :
> 
> nl sal: spe hpe
> 
> but stata reply  :
> 
> : invalid name
> nlsal: refused query, rc=198
> 
> I really don't see what's wrong with my program. If
> anybody has an idea, please...
> 
> clothilde
> 
> 
> 
> 
> 
> 
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