Re: st: backed up

[Stas Kolenikov <skolenik@gmail.com>]

It is not a quadratic form in the parameters; they still enter the
objective function in a nonlinear fashion, generally speaking. If you
have GMM with moments that are linear in parameters, then it is
something like OLS, or an instrumental variable regression, at the
worst :))

On Tue, Jun 29, 2010 at 2:00 PM, sun samn <shwshang@hotmail.com> wrote:
>
>
> Good point. I never thought of  the concave problem before. But my question is about GMM-to minimize a quadratic form, the concave is not a problem, is it?
> thanks!
>
>
>
>> Date: Sun, 27 Jun 2010 13:42:46 -0500
>> Subject: Re: st: backed up
>> From: skolenik@gmail.com
>> To: statalist@hsphsun2.harvard.edu
>>
>> On Sun, Jun 27, 2010 at 12:46 PM, sun samn <shwshang@hotmail.com> wrote:
>>>   Thanks for your response. What do you mean by 'iterations being concave'? I did encounter another situation--the same number kept being iterated but cannot converge.
>>
>> The objective function you maximize must be concave.
>>
>> --
>> Stas Kolenikov, also found at http://stas.kolenikov.name
>> Small print: I use this email account for mailing lists only.
>>
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-- 
Stas Kolenikov, also found at http://stas.kolenikov.name
Small print: I use this email account for mailing lists only.

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