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Re: st: RE: program define quaids_delta


From   nigussie Tefera <nitefera@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: program define quaids_delta
Date   Fri, 5 Jun 2009 08:00:19 -0700 (PDT)

Hello Nelson

Many thanks for your suggestion. It helps me very much. And also thank you very much for your suggestion on aggregation of the commodities. This days, I reduced them to only 12 commodities.  I think it sounds good now. 

Nigussie



----- Original Message ----
From: "Nelson, Carl" <chnelson@illinois.edu>
To: "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Sent: Wednesday, June 3, 2009 4:04:25 PM
Subject: st: RE: program define quaids_delta

Nigussie,

You are apparently looking at the old maximum likelihood code for nonlinear quaids. You
should look at the more recent nlsur code instead. It is much more efficient, easier to
code,  and more robust. A 22 commodity demand system sounds excessive, and almost
certain to be beset by estimation problems. You should probably aggregate down to
a more manageable set.

Carl Nelson
________________________________________
From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] On Behalf Of nigussie Tefera [nitefera@yahoo.com]
Sent: Wednesday, June 03, 2009 6:19 AM
To: statalist@hsphsun2.harvard.edu
Subject: st: program define quaids_delta

Hello dear all

In specify non linear AIDS specification of gamma parameters are important. The specification of gamma for four equations which is given by help desk is given below.

/* gamma */
  matrix `g' = ( 1,  0,  0,  0,  0,  0\ /*
              */  0,  1,  0,  0,  0,  0\ /*
              */  0,  0,  1,  0,  0,  0\ /*
              */ -1, -1, -1,  0,  0,  0\ /*
              */  0,  0,  0,  1,  0,  0\ /*
              */  0,  0,  0,  0,  1,  0\ /*
              */  0, -1,  0, -1, -1,  0\ /*
              */  0,  0,  0,  0,  0,  1\ /*
              */  0,  0, -1,  0, -1, -1\ /*
              */  1,  2,  2,  1,  2,  1 )
  matrix `d'[(2*$NEQN+1), (2*`nm1'+1)] = `g'

If I have 21 equations, how can I specify the gamma matrix? Any help is very much appericiated.




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