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RE: st: Overflow at level 1 in GLLAMM


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Overflow at level 1 in GLLAMM
Date   Tue, 21 Nov 2006 16:23:56 -0000

The simple answer is that this won't help. You 
are fitting a very difficult model and changing the memory
won't make it less difficult. You might get results 
faster, at best, but the answer will be the same. 

Nick 
n.j.cox@durham.ac.uk 

Xiaoheng Zhang
 
> Dear Anders,
> 
> In my sample there are 12 countries as an alternative set and 
> total 2076
> observations(173 firms*12 countries).Frankly I am reluctant 
> to remove any one of
> them from the alternative set.Could I set a large memory for 
> Stata to tackle
> this problem.Currently the memory allocated to Stata is 100mb 
> and the dataset is
> far smaller than 100mb.
 

Anders Alexandersson <andersalex@gmail.com>:
 
> > Kevin (Xiaoheng Zhang <zhangx@tcd.ie>) wonders why overflow 
> can happen
> > when using gllamm for a location choice problem:
> > 
> > > I am running a multilevel regression model by -GLLAMM-.The initial
> > > results are good but then the program reports "overflow 
> at level 1 (173
> > > missing values)".It keeps reporting this msg for a long 
> time.Anyone has a >
> > hint about this? [...] For you information,my command are
> > > -gllamm location eatr cdrug2 dist ap sisters2 wage3 edu3 
> cai share if
> > > highgrow==1&deudmy==0, nocons expand(id choice o) i(parentid2)
> > > lin(mlogit) family(binom) nrf(10) eqs(eatr cdrug2 dist ap 
> sisters2 wage3
> > > edu3 cai share cons) nip(8) trace adapt-
> > 
> > I think that Stata's error message for numerical overflow, 
> r(1400), is
> > helpful here, because gllamm uses numerical integration. The error
> > description for r(1400) begins with this sentence: "You 
> have attempted
> > something that, in the midst of the necessary calculations, has
> > resulted in something too large for Stata to deal with accurately."
> > Thus, I guess that if Kevin tries to estimate a simpler model, the
> > message may disappear. Kevin, for example how many choice categories
> > do you have? Try with fewer choice categories.

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