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Re: st: xtfrontier tvd

From   Scott Merryman <>
Subject   Re: st: xtfrontier tvd
Date   Fri, 6 May 2011 15:05:35 -0500

You can specify more than one technique so that ML will switch between
the algorithms:

. webuse xtfrontier1,clear

. xtfrontier lnwidgets lnworkers lnmachines , tvd difficult tech(nr  dfp)

In the sectors where are you having problems you might try to rescale
the variables so that are all on about the same scale.


On Fri, May 6, 2011 at 1:29 PM, Apurba Shee <> wrote:
> Hi Scott,
> I have tried the –difficult- option that does not help. But when I use
> other maximization technique; for bhhh it shows bhhh requires
> observation level scores, and for dfp and bfgs it shows stepping has
> contracted, resetting dfp/bfgs Hessian, discontinuous region
> encountered cannot compute an improvement. I used xtfrontier lndepvar
> lnindepvars, tvd diff technique(bhhh). Do you know how to make these
> techniques work. I appreciate your help.
> Apurba

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