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RE: st: RE: Frontier,stata 8 & stata 9

From   "Gauri Khanna" <>
Subject   RE: st: RE: Frontier,stata 8 & stata 9
Date   Sat, 10 Jun 2006 06:34:06 +0000

Dear Scott,

Thank you for your response.

I tried the difficult option before but it had not worked. I even looked at the gradient vector to see where it nears zero. It does near zero after several iterations and i thought that since the gradient does not change perhaps I can take that as a cue to stop the iterations at that point. Alternatively, I could arbitrarily set the iterations to a maximum of say 500 and then take the values at that point.

Regarding the maximsation problem, I am not aware of this.. where can i get more information on this?

I guess you do not know have an answer for the stata 8 question where i get a "invalid noconstant" response to my equation:

frontier logoutput logcorarea loglabour logmanure logfertiliserval logtrac logox logirrigation cropdum, uhet(experience age corarea, noconstant).

I tried eliminating the space and inserting square brackets, but no show.

Thank you for advice.



PS this message was resent as I lost my earlier response. Sorry if it reaches you twice.

From: "Scott Merryman" <>
To: <>
Subject: st: RE: Frontier,stata 8 & stata 9
Date: Fri, 9 Jun 2006 17:00:03 -0500

> -----Original Message-----
> From: [mailto:owner-
>] On Behalf Of Gauri Khanna
> Sent: Friday, June 09, 2006 4:57 AM
> To:
> Subject: st: Frontier,stata 8 & stata 9
> 2. I am also running into convergence problems with my frontier
> iterations.
> I decided to assign a lower tolerance level of ltolerance(1e-4) which
> works
> in stata SE8.1 but refuses to converge when I use stata 9 in the office.
> I
> tried 1e-7 for stata 9 but it did not work either in stata 9. Does anyone
> have a solution to the convergence problem in stata 9?

Have you tried using the difficult option or changing the maximization


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